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Embryonic Day (embryonic + day)
Selected AbstractsRepeated exposures to gustatory stimuli produce habituation or positive contrast effects in perinatal ratsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2004G. Andrew Mickley Abstract Adult rats exhibit a decrease in consummatory responses following repeated presentations of a taste (habituation) and an increase in consummatory responses if they experience an upward shift in the magnitude or intensity of a gustatory stimulus (e.g., sucrose or saccharin). These responses do not represent a direct sensorimotor reaction to a gustatory cue, but rather reflect a change in responding based on the memory of a previous taste. Here, we sought to determine if fetal rats could (like adults) adjust their orofacial motor responses based on a memory of recent gustatory experience. Embryonic Day 18 (E18) or Day 19 (E19) rat fetuses received oral lavage with either 0.15 or 0.30% saccharin (SAC). Subsequently, observations of orofacial movements (mouthing and licking) following oral lavage with 0.30% SAC were made 50 min later, 24 hr later, or on postnatal Day 3 (P3). Thus, some animals were in a "shifted" condition in which they first experienced a relatively low concentration of SAC and then a higher one while control rats ("nonshifted") received 0.30% SAC during both taste exposures. Fetuses exhibited evidence of both habituation (with repeated presentation of the 0.30% SAC) and positive contrast effects (PCEs) (following an upward shift in SAC concentration) when retested 50 min after their first exposure to SAC on E19. However, these animals did not exhibit PCEs 24 hr later or 5 days later (on P3). Contrast effects were not observed when the initial SAC exposure was on E18, and habituation responses were variable depending on the time interval between the taste presentations to these animals. Rats with a 5- to 6-day latency between the two taste presentations showed neither PCEs nor habituation. Our data indicate that PCEs and habituation effects emerge at different ages, and their demonstration is dependent upon the latency between the taste presentations. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 176,188, 2004. [source] Classical conditioning in the rat fetus: Involvement of mu and kappa opioid systems in the conditioned responseDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2002William P. Smotherman Abstract When the Embryonic Day 20 (E20) rat fetus is given a conditioning trial involving a paired presentation of an artificial nipple (the conditioned stimulus; CS) with an intraoral infusion of milk (the unconditioned stimulus; US), it shows evidence of classical conditioning when again exposed to the CS during a test trial. Specifically, the fetus shows fewer oral grasp responses (the conditioned response; CR) when continuously presented with the artificial nipple. The present study further investigated this classically conditioned reduction in oral grasping. Separate experiments (a) examined the time course of the reduction in oral grasping (Experiment 1), (b) characterized the time course of mu opioid (Experiment 2) and kappa opioid (Experiment 3) involvement in the CR, and (c) described changes in fetal behavior (Experiment 4) associated with mu and kappa opioid effects on responding to the artificial nipple. The results are discussed in terms of opioid involvement in establishing and maintaining early suckling behavior. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 104,115, 2002. DOI 10.1002/dev.10016 [source] Retinoic acid controls expression of tissue remodeling genes Hmgn1 and Fgf18 at the digit,interdigit junctionDEVELOPMENTAL DYNAMICS, Issue 2 2010Xianling Zhao Abstract Previous studies on retinoic acid receptor (RAR) mutants suggested that retinoic acid (RA) is required for loss of interdigital mesenchyme during digit formation. Here, we report that the RA-generating enzyme retinaldehyde dehydrogenase-2 (Raldh2) is expressed in the interdigital mesenchyme whereas Cyp26b1, controlling RA degradation, is expressed in digits, limiting autopodal RA action to the interdigital zones. Embryonic day 13.5 Raldh2,/, mouse embryos lose expression of the RARE-lacZ RA-reporter transgene and matrix metalloproteinase-11 (Mmp11) throughout the interdigital mesenchyme, while expression of RARb, Fgf18, and high mobility group N1 (Hmgn1) is lost at the digit,interdigit junction. Raldh2,/, autopods exhibit reduced interdigital apoptosis associated with loss of Bmp7 expression, but Bmp2, Bmp4, Msx2, and Fgf8 were unaffected. Although interdigital expression of Hmgn1 was greatly down-regulated in Raldh2,/, autopods, complementary expression of Sox9 in digit cartilage was unaffected. Regulation of Hmgn1 and Fgf18 at the digit,interdigit junction suggests RA controls tissue remodeling as well as apoptosis. Developmental Dynamics 239:665,671, 2010. © 2009 Wiley-Liss, Inc. [source] Increasing renal mass improves survival in anephric rats following metanephros transplantationEXPERIMENTAL PHYSIOLOGY, Issue 1 2007Damian Marshall Renal failure and end-stage renal disease are prevalent diseases associated with high levels of morbidity and mortality, the preferred treatment for which is kidney transplantation. However, the gulf between supply and demand for kidneys remains high and is growing every year. A potential alternative to the transplantation of mature adult kidneys is the transplantation of the developing renal primordium, the metanephros. It has been shown previously, in rodent models, that transplantation of a metanephros can provide renal function capable of prolonging survival in anephric animals. The aim of the present study was to determine whether increasing the mass of transplanted tissue can prolong survival further. Embryonic day 15 rat metanephroi were transplanted into the peritoneum of anaesthetized adult rat recipients. Twenty-one days later, the transplanted metanephroi were anastomosed to the recipient's urinary system, and 35 days following anastomosis the animal's native renal mass was removed. Survival times and composition of the excreted fluid were determined. Rats with single metanephros transplants survived 29 h longer than anephric controls (P < 0.001); animals with two metanephroi survived 44 h longer (P < 0.001). A dilute urine was formed, with low concentrations of sodium, potassium and urea; potassium and urea concentrations were elevated in terminal serum samples, but sodium concentration and osmolality were comparable to control values. These data show that survival time is proportional to the mass of functional renal tissue. While transplanted metanephroi cannot currently provide life-sustaining renal function, this approach may have therapeutic benefit in the future. [source] Studies on the effects of gentamicin on rat metanephric development in vitroNEPHROLOGY, Issue 1-2 2000Luise A Cullen SUMMARY: Reduced nephron endowment has been associated with increased risk of developing essential hypertension and chronic renal failure. Both in vivo and in vitro exposure of developing rat metanephroi to gentamicin has been reported to inhibit metanephric development resulting in reduced nephron endowment. The aim of the present study was to confirm that gentamicin results in reduced nephron endowment in vitro, and to extend understanding of the mechanisms responsible for this reduced endowment. Embryonic day 14 (E14) rat metanephroi were cultured for up to 4 days in serum-free medium with or without 50 ,g/mL gentamicin. Metanephroi cultured in the presence of gentamicin were 25% smaller than control metanephroi after 2 days culture and 30% smaller after 4 days (P < 0.001). This decrease in total metanephric volume was reflected in reduced volumes of ureteric duct epithelium, mesenchyme/interstitium and nephron epithelia. The reduced volume of ureteric duct epithelium in gentamicin-treated metanephroi was associated with a 30% reduction in the number of ureteric duct branch points at 2 days. Metanephroi cultured with gentamicin contained 20% fewer glomeruli than control metanephroi (P < 0.005) at 4 days. These glomeruli were 30% smaller than control glomeruli (P < 0.05). Qualitative observations of Pax-2 immunostained mesenchymal condensates indicated no difference in condensate size, location or morphology. These results confirm that in vitro exposure of developing rat metanephroi to gentamicin results in reduced nephron endowment. The defect in nephrogenesis centres around the inhibition of ureteric duct branching. [source] Classical conditioning in the rat fetus: Temporal characteristics and behavioral correlates of the conditioned responseDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2002William P. Smotherman Abstract This study examined the temporal characteristics and behavioral correlates of the conditioned response (CR) following classical conditioning of the embryonic Day 20 (E20 rat fetus). The conditioning procedure involved pairing of an artificial nipple (the CS) with an infusion of milk (the US) to establish classical conditioning. The test for classical conditioning involved measurement of a stimulus-evoked facial wiping response in a classical conditioning test. Experiment 1 compared the effectiveness of one- and three-trial procedures to establish classical conditioning. Experiment 2, 3, and 4 described the time course for the CR following one- and three-trial conditioning procedures. Experiments 3b and 4b describe the behavioral responses to (a) presentation of the CS at the time of conditioning, (b) infusion of the milk US at the time of conditioning, and (c) reexposure to the CS before the test for classical conditioning. Experiments 5 and 6 exposed the fetus to manipulations that either increased or decreased stretching (a behavior found to be associated with the CR). The results are discussed in terms of the temporal characteristics and behavioral correlates of conditioned and unconditioned responses and their mediation by activity in endogenous mu and kappa opioid systems. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 116,130, 2002. DOI 10.1002/dev.10017 [source] Emergence of long-term memory for conditioned aversion in the rat fetusDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2004Nadège Gruest Abstract Pregnant rats were subjected to garlic essential oil as the conditioned stimulus and 45 min later to LiCl as the unconditioned stimulus either on embryonic Days 15 and 16 (E15 and E16) or on 18 and 19 (E18 and E19). Control dams received only garlic, LiCl, or water. Progenies were tested on garlic drinking 6 weeks after the exposure to the stimuli via the mothers. In the E18 to 19 group, rats that were exposed to paired garlic,LiCl expressed a significant aversion for garlic. In the E15 to 16 group, no significant differences appeared between subgroups. These results confirm that an associative memory can be established before birth and suggests that this ability potentially emerges in a short time window of 3 days at the end of gestation. Moreover, it appears that a long-term memory can be acquired in utero and retained to be expressed postnatally when animals are autonomous. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 189,198, 2004. [source] Absence of tissue inhibitor of metalloproteinases 3 disrupts alveologenesis in the mouseDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2009Sean E. Gill Tissue inhibitors of metalloproteinases (TIMPs) regulate extracellular matrix (ECM) degradation by matrix metalloproteinases (MMPs) throughout lung development. We examined lungs from TIMP3 null mice and found significant air space enlargement compared with wild type (WT) animals during a time course spanning early alveologenesis (post-partum days 1, 5, 9 and 14). Trichrome staining revealed a similar pattern of collagen distribution in the walls of nascent alveoli; however, the alveolar walls of TIMP3 mutant mice appeared to be thinner than controls. Assessment of MMP2 and MMP9 activities by gelatin zymography demonstrated a significant elevation in the active form of MMP2 at post-partum days 1 and 5. Treatment of null pregnant dams with a broad spectrum synthetic metalloproteinase inhibitor, GM6001, on embryonic day 16.5 enhanced the formation of primitive alveoli during the saccular stage of lung development as evidenced by a partial, but significant, rescue of alveolar size in post-partum day 1 animals. We propose that increased MMP activity in the absence of TIMP3 enhances ECM proteolysis, upsetting proper formation of primitive alveolar septa during the saccular stage of alveologenesis. Therefore, TIMP3 indirectly regulates alveolar formation in the mouse. To our knowledge, ours is the first study to demonstrate that in utero manipulation of the TIMP/MMP proteolytic axis, to specifically inhibit proteolysis, significantly affects lung development. [source] Retinoic acid affects craniofacial patterning by changing Fgf8 expression in the pharyngeal ectodermDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 9 2008Makoto Abe Retinoic acid signaling plays important roles in establishing normal patterning and cellular differentiation during embryonic development. In this study, we show that single administration of retinoic acid at embryonic day 8.5 causes homeotic transformation of the lower jaw into upper jaw-like structures. This homeosis was preceded by downregulation of Fgf8 and Sprouty expression in the proximal domain of the first pharyngeal arch. Downregulation of mesenchymal genes such as Dlx5, Hand2, Tbx1 and Pitx2 was also observed. The oropharynx in retinoic acid-treated embryos was severely constricted. Consistent with this observation, Patched expression in the arch endoderm and mesenchyme was downregulated. Thus, retinoic acid affects the expression of subsets of epithelial and mesenchymal genes, possibly disrupting the regional identity of the pharyngeal arch. [source] Busulfan-induced central polydactyly, syndactyly and cleft hand or foot: A common mechanism of disruption leads to divergent phenotypesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2007Takuji Naruse The prevalence of clinical phenotypes that exhibit combinations of central polydactyly, syndactyly, or cleft hand or foot is higher than would be expected for random independent mutations. We have previously demonstrated that maternal ingestion of a chemotherapeutic agent, busulfan, at embryonic day 11 (E11) induces these defects in various combinations in rat embryo limbs. In an effort to determine the mechanism by which busulfan disrupts digital development, we examined cell death by Nile Blue staining and TdT-mediated dUTP nick end labeling (TUNEL) assays; we also carried out whole mount in situ hybridization for fibroblast growth factor-8 (Fgf8), bone morphogenetic protein-4 (Bmp4), and sonic hedgehog (Shh) to examine developmental pathways linked to these defects. In busulfan-treated embryos, diffuse cell death was evident in both ectoderm and mesoderm, peaking at E13. The increased cell death leads to regression of Fgf8 in the apical ectodermal ridge (AER) and Bmp4 and Shh in the underlying mesoderm. The subsequent pattern of interdigital apoptosis and cartilage condensation was variably disrupted. These results suggest that busulfan manifests its teratogenic effects by inducing cell death of both ectoderm and mesoderm, with an associated reduction in tissue and a disruption in the generation of patterning molecules during critical periods of digit specification. [source] Identification of Tgf,1i4 as a downstream target of Foxc1DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2006Paula Sommer Craniofacial development is severely affected by null mutations in Foxc1, indicating a multifunctional role for Foxc1 in ocular, maxilla and mandible, skull and facial gland development. To delineate signaling pathways in which Foxc1 is involved we compared the transcriptomes of whole heads of Foxc1+/+ and Foxc1,/, embryos using a candidate cDNA array comprising genes expressed in the head mesenchyme and ocular region, and a 7K oligo array. Absence of Foxc1 led to downregulation of Stat1 and Galnt4, and upregulation of Tgf,1i4 at embryonic day 13.5 in the developing head mesenchyme. Comparative analyses revealed differences in the expression pattern of Tgf,1i4 in the head mesenchyme of Foxc1,/, and Foxc1+/+ embryos. In the ocular regions of Foxc1,/, embryos, Tgf,1i4 was expressed in higher levels in the conjunctival epithelium and in the condensing mesenchyme on the nasal aspect of the developing eye while in wild-type embryos more intense expression was seen in the mesenchyme on the temporal aspect of the eye. Such data indicate that Foxc1 regulation of Tgf,1i4 is complex and may be cell-type dependent. Analysis of the regulation of Tgf,1i4 by Foxc1 in a more homogenous cell population, mesenchymal cells isolated from the periocular region revealed that, in these cells, Foxc1 negatively regulated Tgf,1i4 expression, presumably via secreted factors such as TGF-,1. Since Foxc1 expression is essential for normal craniofacial development, it is possible that its downstream targets play a role in the development of the phenotypes associated with null mutations in Foxc1. [source] Localization of Indian hedgehog and PTH/PTHrP receptor expression in relation to chondrocyte proliferation during mouse bone developmentDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2005Helen E. MacLean We have developed a useful approach to examine the pattern of gene expression in comparison to cell proliferation, using double in situ hybridization and immunofluorescence. Using this system, we examined the expression of Indian hedgehog (Ihh) and PTH/PTHrP receptor (PPR) mRNA in relation to chondrocyte proliferation during embryonic mouse bone development. Both genes are expressed strongly in prehypertrophic and early hypertrophic chondrocytes, and there is a strong correlation between upregulation of both Ihh and PPR expression and chondrocyte cell cycle arrest. At embryonic day (E14.5), PPR mRNA upregulation begins in the columnar chondrocytes just prior to cell cycle exit, but at later time points expression is only observed in the postproliferative region. In contrast, Ihh mRNA expression overlaps slightly with the region of columnar proliferating chondrocytes at all stages. This study provides further evidence that in the developing growth plate, cell cycle exit and upregulation of Ihh and PPR mRNA expression are coupled. [source] Gene expression in the efferent ducts, epididymis, and vas deferens during embryonic development of the mouseDEVELOPMENTAL DYNAMICS, Issue 9 2010Elizabeth M. Snyder Abstract The tissues of the male reproductive tract are characterized by distinct morphologies, from highly coiled to un-coiled. Global gene expression profiles of efferent ducts, epididymis, and vas deferens were generated from embryonic day 14.5 to postnatal day 1 as tissue-specific morphologies emerge. Expression of homeobox genes, potential mediators of tissue-specific morphological development, was assessed. Twenty homeobox genes were identified as either tissue-enriched, developmentally regulated, or both. Additionally, ontology analysis demonstrated cell adhesion to be highly regulated along the length of the reproductive tract. Regulators of cell adhesion with variable expression between the three tissues were identified including Alcam, various cadherins, and multiple integrins. Immunofluorescence localization of the cell adhesion regulators POSTN and CDH2 demonstrated cell adhesion in the epithelium and mesenchyme of the epididymis may change throughout development. These results suggest cell adhesion may be modulated in a tissue-specific manner, playing an important role in establishing each tissue's final morphology. Developmental Dynamics 239:2479,2491, 2010. © 2010 Wiley-Liss, Inc. [source] Regional expression of MTG genes in the developing mouse central nervous systemDEVELOPMENTAL DYNAMICS, Issue 8 2009Amin Alishahi Abstract Myeloid translocation gene (MTG) proteins are transcriptional repressors that are highly conserved across species. We studied the expression of three members of this gene family, MTGR1, MTG8, and MTG16 in developing mouse central nervous system by in situ hybridization. All of these genes are detected as early as embryonic day 11.5. Because these genes are known to be induced by proneural genes during neurogenesis, we analyzed the expression of MTG genes in relation to two proneural genes, Neurog2 (also known as Ngn2 or Neurogenin 2) and Ascl1 (also known as Mash1). While MTGR1 are generally expressed in regions that also express Neurog2, MTG8 and MTG16 expression is associated more tightly with that of Ascl1 -expressing neural progenitor cells. These results suggest the possibility that expression of MTG genes is differentially controlled by specific proneural genes during neurogenesis. Developmental Dynamics 238:2095,2102, 2009. © 2009 Wiley-Liss, Inc. [source] Genetic disruption of CYP26B1 severely affects development of neural crest derived head structures, but does not compromise hindbrain patterningDEVELOPMENTAL DYNAMICS, Issue 3 2009Glenn Maclean Abstract Cyp26b1 encodes a cytochrome-P450 enzyme that catabolizes retinoic acid (RA), a vitamin A derived signaling molecule. We have examined Cyp26b1,/, mice and report that mutants exhibit numerous abnormalities in cranial neural crest cell derived tissues. At embryonic day (E) 18.5 Cyp26b1,/, animals exhibit a truncated mandible, abnormal tooth buds, reduced ossification of calvaria, and are missing structures of the maxilla and nasal process. Some of these abnormalities may be due to defects in formation of Meckel's cartilage, which is truncated with an unfused distal region at E14.5 in mutant animals. Despite the severe malformations, we did not detect any abnormalities in rhombomere segmentation, or in patterning and migration of anterior hindbrain derived neural crest cells. Abnormal migration of neural crest cells toward the posterior branchial arches was observed, which may underlie defects in larynx and hyoid development. These data suggest different periods of sensitivity of anterior and posterior hindbrain neural crest derivatives to elevated levels of RA in the absence of CYP26B1. Developmental Dynamics 238:732,745, 2009. © 2009 Wiley-Liss, Inc. [source] C-myc as a modulator of renal stem/progenitor cell populationDEVELOPMENTAL DYNAMICS, Issue 2 2009Martin Couillard Abstract The role of c - myc has been well-studied in gene regulation and oncogenesis but remains elusive in murine development from midgestation. We determined c - myc function during kidney development, organogenesis, and homeostasis by conditional loss of c - myc induced at two distinct phases of nephrogenesis, embryonic day (e) 11.5 and e17.5. Deletion of c - myc in early metanephric mesenchyme (e11.5) led to renal hypoplasia from e15.5 to e17.5 that was sustained until adulthood (range, 20,25%) and, hence, reproduced the human pathologic condition of renal hypoplasia. This phenotype resulted from depletion of c - myc,positive cells in cap mesenchyme, causing a ,35% marked decrease of Six2- and Cited1-stem/progenitor population and of proliferation that likely impaired self-renewal. By contrast, c - myc loss from e17.5 onward had no impact on late renal differentiation/maturation and/or homeostasis, providing evidence that c - myc is dispensable during these phases. This study identified c - myc as a modulator of renal organogenesis through regulation of stem/progenitor cell population. Developmental Dynamics 238:405,414, 2009. © 2009 Wiley-Liss, Inc. [source] Left-asymmetric expression of Galanin in the linear heart tube of the mouse embryo is independent of the nodal co-receptor gene crypticDEVELOPMENTAL DYNAMICS, Issue 12 2008Axel Schweickert Abstract Only very few left/right asymmetrically expressed genes are known in the mammalian embryo. In a screen for novel factors we identified the gene encoding the neuropeptide Galanin in mouse. At embryonic day (E) 8.5 asymmetric mRNA transcription was found in the left half of the linear heart tube. During heart looping and morphogenesis expression became restricted to the atrio-ventricular (AV) canal, followed by specific staining of the AV-node and AV-rings in the four-chambered heart. Expression was inverted in inv/inv and randomized in homozygous iv mutant embryos. Left-sided heart-specific transcription of mouse Gal thus should be controlled by the left-right pathway. The asymmetric pattern was retained in cryptic mutant embryos, in which the Nodal signaling cascade is disrupted. Surprisingly, Pitx2c was found to be expressed in 50% of cryptic mutant hearts as well, suggesting that some aspects of asymmetric gene expression in the heart are independent of cryptic. Developmental Dynamics 237:3557,3564, 2008. © 2008 Wiley-Liss, Inc. [source] Analysis of the IKK,/NF-,B signaling pathway during embryonic angiogenesisDEVELOPMENTAL DYNAMICS, Issue 10 2008Yanjun Hou Abstract The nuclear factor-,B (NF-,B) signaling pathway regulates cellular growth, survival, differentiation and development. In this study, the functions of I,B kinase (IKK), in angiogenesis during mouse development were examined. Conditional disruption of the Ikk, locus in endothelial cells using the well-characterized Tie2-Cre transgene resulted in embryonic lethality between embryonic day (E) 13.5 and E15.5. Examination of the mutant embryos revealed that while deletion of Ikk, occurred in endothelial cells throughout the embryo, only the vascular network in the fetal liver was affected. Disruption of the fetal liver vasculature was accompanied by decreased cell proliferation and increased apoptosis of hepatocytes, but hematopoiesis was not affected. Increased apoptosis was not observed outside of fetal liver in the mutant embryos. These results indicate that the IKK,/NF-,B pathway plays a previously unappreciated role in development of the sinusoidal vasculature in the fetal liver and additionally that this pathway is critical in the crosstalk between endothelial cells and hepatocytes during mouse development. Developmental Dynamics 237:2926,2935, 2008. © 2008 Wiley-Liss, Inc. [source] Ventral specification and perturbed boundary formation in the mouse midbrain in the absence of Hedgehog signalingDEVELOPMENTAL DYNAMICS, Issue 5 2008Jennifer L. Fogel Abstract Although Hedgehog (HH) signaling plays a critical role in patterning the ventral midbrain, its role in early midbrain specification is not known. We examined the midbrains of sonic hedgehog (Shh) and smoothened (Smo) mutant mice where HH signaling is respectively attenuated and eliminated. We show that some ventral (Evx1+) cell fates are specified in the Shh,/, mouse in a Ptc1 - and Gli1 -independent manner. HH-independent ventral midbrain induction was further confirmed by the presence of a Pax7 -negative ventral midbrain territory in both Shh,/, and Smo,/, mice at and before embryonic day (E) 8.5. Midbrain signaling centers are severely disrupted in the Shh,/, mutant. Interestingly, dorsal markers are up-regulated (Wnt1, Gdf7, Pax7), down-regulated (Lfng), or otherwise altered (Zic1) in the Shh,/, midbrain. Together with the increased cell death seen specifically in Shh,/, dorsal midbrains (E8.5,E9), our results suggest specific regulation of dorsal patterning by SHH, rather than a simple deregulation due to its absence. Developmental Dynamics 237:1359-1372, 2008. © 2008 Wiley-Liss, Inc. [source] Expression pattern of Popdc2 during mouse embryogenesis and in the adultDEVELOPMENTAL DYNAMICS, Issue 3 2008Alexander Froese Abstract The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life. Developmental Dynamics 237:780,787, 2008. © 2008 Wiley-Liss, Inc. [source] Identification of erythroid-enriched gene expression in the mouse embryonic yolk sac using microdissected cellsDEVELOPMENTAL DYNAMICS, Issue 2 2008Latasha C. Redmond Abstract Little is known about the genes that control the embryonic erythroid program. Laser capture microdissection was used to isolate primitive erythroid precursors and epithelial cells from frozen sections of the embryonic day 9.5 yolk sac. The RNA samples were amplified and labeled for hybridization to Affymetrix GeneChip Mouse Genome 430A 2.0 arrays. Ninety-one genes are expressed significantly higher in erythroid than in epithelial cells. Ingenuity pathway analysis indicates that many of these erythroid-enriched genes cluster in highly significant biological networks. One of these networks contains RBTN2/LMO2, SCL/TAL1, and EKLF/KLF1, three of the very few genes required for primitive erythropoiesis. Quantitative real-time polymerase chain reaction was used to verify that platelet factor 4, reelin, thrombospondin - 1, and muscleblind - like 1 mRNA is erythroid-enriched. These genes have established roles in development or differentiation in other systems, and are, therefore, good candidates for regulating primitive erythropoiesis. These results provide a catalog of genes expressed during primitive erythropoiesis. Developmental Dynamics 237:436,446, 2008. © 2008 Wiley-Liss, Inc. [source] Development of murine hepatic sinusoidal endothelial cells characterized by the expression of hyaluronan receptorsDEVELOPMENTAL DYNAMICS, Issue 8 2007Hidenori Nonaka Abstract Endothelial cells (ECs) display distinct structural and functional characteristics depending on the tissue and developmental stage; however, the development of tissue-specific ECs remains poorly understood. Here, we describe the development of hepatic sinusoids in mice based on the expression of hyaluronan receptors Stab2 and Lyve-1. Flk-1+ cells in and around the liver bud begin to express Stab2 at embryonic day (E) 9.5, before the formation of vascular lumen. Hepatic sinusoidal endothelial cells (HSECs) begin to express Lyve-1 at E10.5, and both markers continue to be expressed in HSECs thereafter. Although HSECs and lymphatic ECs (LECs) are known to share functional and phenotypic characteristics, we clearly show that HSECs can be distinguished from LECs by the expression of molecular markers and higher endocytotic activity. Our results provide new insight into the development of tissue-specific ECs and phenotypic criteria to distinguish HSECs from other types of ECs, including LECs. Developmental Dynamics 236:2258,2267, 2007. © 2007 Wiley-Liss, Inc. [source] Sexual dimorphism of g-protein subunit Gng13 expression in the cortical region of the developing mouse ovaryDEVELOPMENTAL DYNAMICS, Issue 7 2007Akihiro Fujino Abstract In our search for genes required for the development and function of mouse gonads, we identified Gng13 (guanine nucleotide binding protein 13, gamma), a gene with an embryonic expression pattern highly restricted to the ovary. Based on reverse transcriptase-polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization, Gng13 is expressed in both XX and XY gonads at embryonic day (E) 11.5, but becomes up-regulated in the XX gonad by E12.5. Expression is retained after treatment with busulfan, a chemical known to eliminate germ cells, pointing to the soma as a site of Gng13 transcription. In situ hybridization of embryonic ovarian tissue sections further localized the expression to the cortex of the developing XX gonad. Gng13 expression in the adult is also highly restricted. Northern blot analyses and Genomic Institute of the Novartis Research Foundation expression profiling of adult tissues detected very high expression in the cerebrum and cerebellum, in addition to, a weaker signal in the ovary. Gng13 belongs to a well-known family of signal transduction molecules with functions in many aspects of development and organ physiology. Here, we report that, in the developing mouse embryo, expression of Gng13 mRNA is highly restricted to the cortex of the XX gonad during sexual differentiation, suggesting a role for this gene during ovarian development. Developmental Dynamics 236:1991,1996, 2007. © 2007 Wiley-Liss, Inc. [source] Identification of molecular markers that are expressed in discrete anterior,posterior domains of the endoderm from the gastrula stage to mid-gestationDEVELOPMENTAL DYNAMICS, Issue 7 2007Billie A. Moore-Scott Abstract Little is known about how the endoderm germ layer is patterned along the anterior,posterior (A-P) axis before the formation of a gut tube (embryonic day [e] 7.5,8.5 in mouse), largely due to a paucity of molecular markers of endoderm. In particular, there are few genes that mark posterior domains of endoderm that give rise to the midgut and hindgut. We have identified 8 molecular markers that are expressed in discrete domains of the gastrula stage endoderm (e7.5), suggesting that a significant level of pattern exists in the endoderm before the formation of a gut tube. Three genes Tmprss2, NM_029639, and Dsp are expressed in a presumptive midgut domain overlying the node, a domain for which molecular markers have not previously been identified. Two genes, Klf5 and Epha2 are expressed in posterior endoderm associated with the primitive streak. Expression of these five genes persists in the midgut and/or hindgut at e8.5, 9.5 and 10.5, suggesting that these genes are markers of these domains throughout these stages of development. We have identified three genes Slc39a8, Amot, and Dp1l1, which are expressed in the visceral endoderm at e7.5. Starting at e9.5, Dp1l1 is expressed de novo in the liver, midgut, and hindgut. Our findings suggest that presumptive midgut and hindgut domains are being established at the molecular level by the end of gastrulation, earlier than previously thought, and emphasize the importance of endoderm patterning before the formation of the fetal gut. Developmental Dynamics 236:1997,2003, 2007. © 2007 Wiley-Liss, Inc. [source] Transient expression of thyroid hormone nuclear receptor TR,2 sets S opsin patterning during cone photoreceptor genesisDEVELOPMENTAL DYNAMICS, Issue 5 2007M.L. Applebury Abstract Cone photoreceptors in the murine retina are patterned by dorsal repression and ventral activation of S opsin. TR,2, the nuclear thyroid hormone receptor , isoform 2, regulates dorsal repression. To determine the molecular mechanism by which TR,2 acts, we compared the spatiotemporal expression of TR,2 and S opsin from embryonic day (E) 13 through adulthood in C57BL/6 retinae. TR,2 and S opsin are expressed in cone photoreceptors only. Both are transcribed by E13, and their levels increase with cone genesis. TR,2 is expressed uniformly, but transiently, across the retina. mRNA levels are maximal by E17 at completion of cone genesis and again minimal before P5. S opsin is also transcribed by E13, but only in ventral cones. Repression in dorsal cones is established by E17, consistent with the occurrence of patterning during cone cell genesis. The uniform expression of TR,2 suggests that repression of S opsin requires other dorsal-specific factors in addition to TR,2. The mechanism by which TR,2 functions was probed in transgenic animals with TR,2 ablated, TR,2 that is DNA binding defective, and TR,2 that is ligand binding defective. These studies show that TR,2 is necessary for dorsal repression, but not ventral activation of S opsin. TR,2 must bind DNA and the ligand T3 (thyroid hormone) to repress S opsin. Once repression is established, T3 no longer regulates dorsal S opsin repression in adult animals. The transient, embryonic action of TR,2 is consistent with a role (direct and/or indirect) in chromatin remodeling that leads to permanent gene silencing in terminally differentiated, dorsal cone photoreceptors. Developmental Dynamics 236:1203,1212, 2007. © 2007 Wiley-Liss, Inc. [source] Analysis of pancreatic endocrine development in GDF11-deficient miceDEVELOPMENTAL DYNAMICS, Issue 11 2006Darwin S. Dichmann Abstract Here, we examine the role of GDF11 in pancreatic development. Using in situ hybridization and reverse transcriptase-polymerase chain reaction analyses, we show that Gdf11 transcripts are expressed in embryonic pancreas epithelium before the secondary transition but decrease rapidly afterward. To determine the function of GDF11 during pancreas development, we analyzed Gdf11,/, mouse embryos. In such embryos, pancreas size is twofold reduced at embryonic day (E) 18 compared with wild-type littermates. Quantification of the different tissue compartments shows a specific hypoplasia of the exocrine compartment, while the endocrine and ductal compartments are unaffected. Notably, NGN3+ endocrine precursor cells are increased fourfold at E18, although the amount of endocrine cells in the pancreas of these animals is unchanged compared with wild-type littermates. Similarly, the maturation of endocrine cells as well as the ratio between ,- and ,-cells appears normal. Developmental Dynamics 235:3016,3025, 2006. © 2006 Wiley-Liss, Inc. [source] Expression of qBrn-1, a new member of the POU gene family, in the early developing nervous system and embryonic kidneyDEVELOPMENTAL DYNAMICS, Issue 4 2006Lei Lan Abstract It has been shown that POU domain genes play critical roles in the development of the nervous system. We have obtained a new member of the class III POU domain genes, qBrn-1, from the cDNA library of embryonic day 5 quail and have made an extensive expression pattern analysis of qBrn-1 and qBrn-2 throughout the early embryonic development by in situ hybridization. With a specific antibody we prepared, further analysis by immunohistochemistry showed that the location of qBrn-1 protein was consistent with that of the transcripts in the early developing quail. Our results showed that both qBrn-1 and qBrn-2 were preferentially expressed in the developing central nervous system, and their transcripts were initially detected in the neural plate and later in the distinct regions of the neural tube with a stage-dependent pattern. Moreover, their expression was also detected in both notochord and neural crests. However, qBrn-1 signal, different from qBrn-2, was more widely found in the auditory pits, branchial arches, and in the mesodermal components of the developing kidney. And the expression of qBrn-1 in nephric region was earlier and wider than that of mouse Brn-1, suggesting the characteristic function of qBrn-1 in the kidney formation. The distinct dynamic expression patterns of qBrn-1 and qBrn-2 indicate multiple roles of the class III POU genes in quail neurogenesis and organogenesis. Developmental Dynamics 235:1107,1114, 2006. © 2006 Wiley-Liss, Inc. [source] Dlk1 expression marks developing endothelium and sites of branching morphogenesis in the mouse embryo and placentaDEVELOPMENTAL DYNAMICS, Issue 4 2006Aleksey Yevtodiyenko Abstract The protein product of the Delta-like 1 (Dlk1) gene belongs to the Delta-Notch family of signaling molecules, proteins involved in cell fate determination in many tissues during development. The DLK1 protein is believed to function as a growth factor, maintaining the proliferative state of undifferentiated cells, and is usually down-regulated as immature cells differentiate. The expression pattern of the DLK1 protein has been described in certain human tissues; however, Dlk1 expression is not well understood in the mouse, the most tractable mammalian genetic model system. To better understand the role of Dlk1 in embryonic development, the tissue-specific expression pattern of Dlk1 mRNA during mouse embryogenesis was analyzed by in situ hybridization. In embryonic day 12.5 (e12.5) embryos, high levels of Dlk1 were found in the developing pituitary, pancreas, lung, adrenal, and many mesodermally derived tissues. Strikingly, Dlk1 expression also marks the growing branches of organs that develop through the process of branching morphogenesis. At e16.5, Dlk1 expression is down-regulated in most tissues but remains in the pituitary, the adrenal gland, and in skeletal muscle. In the placenta, expression of Dlk1 is detected in endothelial cells lining the fetal blood vessels of the labyrinth. This pattern is distinct from that seen in the human placenta and suggests a role for Dlk1 in regulating maternal,fetal interactions. Developmental Dynamics 235:1115,1123, 2006. © 2006 Wiley-Liss, Inc. [source] Analysis of Meox - 2 mutant mice reveals a novel postfusion-based cleft palateDEVELOPMENTAL DYNAMICS, Issue 2 2006Jiu-Zhen Jin Abstract Cleft palate represents a common human congential disease involving defects in the development of the secondary palate. Major steps in mammalian palatogenesis include vertical growth, elevation, and fusion of the palate shelves. Our current study with the homeobox gene Meox - 2 during mouse secondary palate development reveals a novel postfusion-based mechanism for cleft palate. Meox - 1 and Meox - 2 are two functionally related homeobox genes playing important roles in somitogenesis and limb muscle differentiation. We found that the expression of Meox - 2, not Meox - 1, marks the specification of early mouse palatal mesenchymal cells in the maxillary processes at embryonic day 11.5 (E11.5). From E12.5 to E15.5, the expression of Meox - 2 occupies only the posterior part of the palate, providing an early molecular marker for the anterior,posterior polarity in mouse secondary palate formation. A total of 35.3% of Meox - 2,/, (n = 17) and 25.5% of Meox - 2+/, (n = 55) mouse embryos display a cleft palate phenotype at E15.5, indicating that the reduction of Meox - 2 function is associated with susceptibility to cleft palate. Unlike previously reported clefts, none of the clefts found in Meox - 2 mutants contain any epithelial sheets in the medial edge areas, and detailed examination revealed that the clefts resulted from the breakdown of newly fused palates. This article is the first report of a gene required to maintain adherence of the palatal shelves after fusion. Developmental Dynamics 235:539,546, 2006. © 2005 Wiley-Liss, Inc. [source] Comprehensive expression atlas of fibroblast growth factors and their receptors generated by a novel robotic in situ hybridization platformDEVELOPMENTAL DYNAMICS, Issue 2 2005Murat Burak Yaylaoglu Abstract A recently developed robotic platform termed "Genepaint" can carry out large-scale nonradioactive in situ hybridization (ISH) on tissue sections. We report a series of experiments that validate this novel platform. Signal-to-noise ratio and mRNA detection limits were comparable to traditional ISH procedures, and hybridization was transcript-specific, even in cases in which probes could have hybridized to several transcripts of a multigene family. We established an atlas of expression patterns of fibroblast growth factors (Fgfs) and their receptors (Fgfrs) for the embryonic day 14.5 mouse embryo. This atlas provides a comprehensive overview of previously known as well as novel sites of expression for this important family of signaling molecules. The Fgf/Fgfr atlas was integrated into the transcriptome database (www.genepaint.org), where individual Fgf and Fgfr expression patterns can be interactively viewed at cellular resolution and where sites of expressions can be retrieved using an anatomy-based search. Developmental Dynamics 234:371,386, 2005. © 2005 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||