Developmental Dynamics (developmental + dynamics)

Distribution by Scientific Domains

Selected Abstracts

bmp2b and bmp4 are dispensable for zebrafish tooth development

Sarah B. Wise
Abstract Bone morphogenetic protein (Bmp) signaling has been shown to play important roles in tooth development at virtually all stages from initiation to hard tissue formation. The specific ligands involved in these processes have not been directly tested by loss-of-function experiments, however. We used morpholino antisense oligonucleotides and mutant analysis in the zebrafish to reduce or eliminate the function of bmp2b and bmp4, two ligands known to be expressed in zebrafish teeth and whose mammalian orthologs are thought to play important roles in tooth development. Surprisingly, we found that elimination of function of these two genes singly and in combination did not prevent the formation of mature, attached teeth. The mostly likely explanation for this result is functional redundancy with other Bmp ligands, which may differ between the zebrafish and the mouse. Developmental Dynamics 239:2534,2546, 2010. © 2010 Wiley-Liss, Inc. [source]

Atypical molecular profile for joint development in the avian costal joint

B.B. Winslow
Abstract Development of synovial joints involves generation of cartilaginous anlagen, formation of interzones between cartilage anlagen, and cavitation of interzones to produce fluid filled cavities. Interzone development is not fully understood, but interzones are thought to develop from skeletogenic cells that are inhibited from further chondrogenic development by a cascade of gene expression including Wnt and Bmp family members. We examined the development of the rarely studied avian costal joint to better understand mechanisms of joint development. The costal joint is found within ribs, is morphologically similar to the metatarsophalangeal joint, and undergoes cavitation in a similar manner. In contrast to other interzones, Wnt14/9a, Gdf5, Chordin, Barx1, and Bapx1 are absent from the costal joint interzone, consistent with the absence of active ,-catenin and phosphorylated Smad 1/5/8. However Autotaxin and Noggin are expressed. The molecular profile of the costal joint suggests there are alternative mechanisms of interzone development. Developmental Dynamics 239:2547,2557, 2010. © 2010 Wiley-Liss, Inc. [source]

Expression, functional, and structural analysis of proteins critical for otoconia development

Yinfang Xu
Abstract Otoconia, developed during late gestation and perinatal stages, couple mechanic force to the sensory hair cells in the vestibule for motion detection and bodily balance. In the present work, we have investigated whether compensatory deposition of another protein(s) may have taken place to partially alleviate the detrimental effects of Oc90 deletion by analyzing a comprehensive list of plausible candidates, and have found a drastic increase in the deposition of Sparc-like 1 (aka Sc1 or hevin) in Oc90 null versus wt otoconia. We show that such up-regulation is specific to Sc1, and that stable transfection of Oc90 and Sc1 full-length expression constructs in NIH/3T3 cells indeed promotes matrix calcification. Analysis and modeling of Oc90 and Sc1 protein structures show common features that may be critical requirements for the otoconial matrix backbone protein. Such information will serve as the foundation for future regenerative purposes. Developmental Dynamics 239:2659,2673, 2010. © 2010 Wiley-Liss, Inc. [source]

Recombinant EDA or Sonic Hedgehog rescue the branching defect in Ectodysplasin A pathway mutant salivary glands in vitro

K.L. Wells
Abstract Hypohidrotic ectodermal dysplasia (HED) is characterized by defective ectodermal organ development. This includes the salivary glands (SGs), which have an important role in lubricating the oral cavity. In humans and mice, HED is caused by mutations in Ectodysplasin A (Eda) pathway genes. Various phenotypes of the mutant mouse EdaTa/Ta, which lacks the ligand Eda, can be rescued by maternal injection or in vitro culture supplementation with recombinant EDA. However, the response of the SGs to this treatment has not been investigated. Here, we show that the submandibular glands (SMGs) of EdaTa/Ta mice exhibit impaired branching morphogenesis, and that supplementation of EdaTa/Ta SMG explants with recombinant EDA rescues the defect. Supplementation of EdardlJ/dlJ SMGs with recombinant Sonic hedgehog (Shh) also rescues the defect, whereas treatment with recombinant Fgf8 does not. This work is the first to test the ability of putative Eda target molecules to rescue Eda pathway mutant SMGs. Developmental Dynamics 239:2674,2684, 2010. © 2010 Wiley-Liss, Inc. [source]

Zebrafish notch signalling pathway mutants exhibit trunk vessel patterning anomalies that are secondary to somite misregulation

Christina Therapontos
Abstract The Notch signalling pathway mutants, after-eight (aei), beamter (bea), and deadly-seven (des) have previously been used to study somitogenesis and neurogenesis. Notch signalling has also been shown to have roles in vascular development. However, vascular development in each of these three Notch mutants has not been described, and so their potential usefulness for further understanding the role of Notch signalling in angiogenesis is unknown. Here we demonstrate each of the mutants also exhibit vascular defects in inter-somitic vessel (ISV) positioning and patterning. Ectopic filopodia were also observed on the ISVs of the mutants. Ectopic filopodia are not due to loss of dll4. Somite expression of known vascular guidance cues, efnb2, sema3a2, and plexinD1 are disrupted, suggesting that the ISV vascular phenotype is due to disruption of these cues. Developmental Dynamics 239:2761,2768, 2010. © 2010 Wiley-Liss, Inc. [source]

Comparative expression pattern analysis of the highly conserved chemokines SDF1 and CXCL14 during amniote embryonic development

Clara García-Andrés
Abstract Chemokines are secreted proteins with essential roles in leukocyte trafficking and cell migration during embryogenesis. CXCL14 displays a degree of evolutionary conservation unmatched by any other chemokine except for SDF1(CXCL12). However, its role during embryogenesis has not been studied. Here we describe the expression pattern of mouse and chicken CXCL14 during embryogenesis and compare it with that of SDF1. CXCL14 is widely expressed in embryonic ectoderm and shows a restricted and dynamic expression pattern in paraxial mesoderm, mesonephros, neural tube, and limbs. During limb development, CXCL14 marks a unique connective tissue subset that surrounds developing tendons. Comparison of CXCL14 and SDF1 reveals mostly non-overlapping or complementary expression patterns, suggesting an interactive regulation of developmental processes by these two chemokines. Our study identifies CXCL14 as a novel marker of tendon connective tissue and provides a conceptual framework for the coordinated action of two highly conserved chemokines in embryonic development. Developmental Dynamics 239:2769,2777, 2010. © 2010 Wiley-Liss, Inc. [source]

Drosophila CtBP regulates proliferation and differentiation of eye precursors and complexes with Eyeless, Dachshund, Dan, and Danr during eye and antennal development

Chinh Q. Hoang
Abstract Specification factors regulate cell fate in part by interacting with transcriptional co-regulators like CtBP to regulate gene expression. Here, we demonstrate that CtBP forms a complex or complexes with the Drosophila melanogaster Pax6 homolog Eyeless (Ey), and with Distal antenna (Dan), Distal antenna related (Danr), and Dachshund to promote eye and antennal specification. Phenotypic analysis together with molecular data indicate that CtBP interacts with Ey to prevent overproliferation of eye precursors. In contrast, CtBP,dan,danr triple mutant adult eyes have significantly fewer ommatidia than CtBP single or dan,danr double mutants, suggesting that the CtBP/Dan/Danr complex functions to recruit ommatidia from the eye precursor pool. Furthermore, CtBP single and to a greater extent CtBP,dan,danr triple mutants affect the establishment and maintenance of the R8 precursor, which is the founding ommatidial cell. Thus, CtBP interacts with different eye specification factors to regulate gene expression appropriate for proliferative vs. differentiative stages of eye development. Developmental Dynamics 239:2367,2385, 2010. © 2010 Wiley-Liss, Inc. [source]

MMP-2 contributes to the development of the mouse ventral prostate by impacting epithelial growth and morphogenesis

Alexandre Bruni-Cardoso
Abstract Epithelial growth, branching, and canalization are important morphogenetic events of the rodent ventral prostate (VP) that take place during the first postnatal week. In this study, we evaluated the effect of knocking out MMP-2 (MMP-2,/,), by examining developmental and structural aspects of the VP in MMP-2,/, mice. Neonate (day 6) MMP-2,/, mice showed fewer epithelial tips, a lower epithelial cell proliferation rate, and also reticulin fiber accumulation. The VP of adult MMP-2,/, mice showed lower relative weight, smaller epithelial and smooth-muscle cell volume, and a larger amount of thicker reticulin fibers. No differences in cell proliferation or apoptotic index were noted between adult MMP-2,/, and wild-type mice. MMP-9 was found in the adult MMP-2,/,, but not in the wild-type. In conclusion, MMP-2 function is essential for the epithelial morphogenesis of the mouse VP, and expression of MMP-9 is not sufficient for acquisition of the normal adult histology. Developmental Dynamics 239:2386,2392, 2010. © 2010 Wiley-Liss, Inc. [source]

Gene expression in the efferent ducts, epididymis, and vas deferens during embryonic development of the mouse

Elizabeth 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]

Cath6, a bHLH atonal family proneural gene, negatively regulates neuronal differentiation in the retina

Fumi Kubo
Abstract Basic helix,loop,helix (bHLH) transcription factors play important roles in cell type specification and differentiation during the development of the nervous system. In this study, we identified a chicken homolog of Atonal 8/ath6 (Cath6) and examined its role in the developing retina. Unlike other Atonal-family proneural genes that induce neuronal differentiation, Cath6 was expressed in stem cell-like progenitor cells in the marginal region of the retina, and its overexpression inhibited neuronal differentiation. A Cath6 fused with a VP16 transactivation domain recapitulated the inhibitory effect of Cath6 on neuronal differentiation, indicating that Cath6 functions as a transcription activator. These results demonstrate that Cath6 constitutes a unique member of the Atonal-family of genes in that it acts as a negative regulator of neuronal differentiation. Developmental Dynamics 239:2492,2500, 2010. © 2010 Wiley-Liss, Inc. [source]

Neuron-specific expression of atp6v0c2 in zebrafish CNS

Ah-Young Chung
Abstract Vacuolar ATPase (V-ATPase) is a multi-subunit enzyme that plays an important role in the acidification of a variety of intracellular compartments. ATP6V0C is subunit c of the V0 domain that forms the proteolipid pore of the enzyme. In the present study, we investigated the neuron-specific expression of atp6v0c2, a novel isoform of the V-ATPase c-subunit, during the development of the zebrafish CNS. Zebrafish atp6v0c2 was isolated from a genome-wide analysis of the zebrafish mibta52b mutant designed to identify genes differentially regulated by Notch signaling. Whole-mount in situ hybridization revealed that atp6v0c2 is expressed in a subset of CNS neurons beginning several hours after the emergence of post-mitotic neurons. The ATP6V0C2 protein is co-localized with the presynaptic vesicle marker, SV2, suggesting that it is involved in neurotransmitter storage and/or secretion in neurons. In addition, the loss-of-function experiment suggests that ATP6V0C2 is involved in the control of neuronal excitability. Developmental Dynamics 239:2501,2508, 2010. © 2010 Wiley-Liss, Inc. [source]

Ooplasmic segregation in the zebrafish zygote and early embryo: Pattern of ooplasmic movements and transport pathways

Ricardo Fuentes
Abstract Patterns of cytoplasmic movements and organization of transport pathways were examined in live or fixed zygotes and early zebrafish embryos using a variety of techniques. The zygote blastodisc grows by accumulation of ooplasm, transported to the animal pole from distinct sectors of ecto- and endoplasm at different speeds and developmental periods, using specific pathways or streamers. Slow transport (5 ,m/min) occurs during the first interphase along short streamers, whereas fast transport (9.6,40 ,m/min) takes place during the first cleavage division along axial and meridional streamers. Interconnections between streamers allow cargoes to change their speed and final destination. A similar sequence of events occurs during the following divisions. A complex network of microtubules and actin filaments in the endo- and ectoplasm appears to be involved in the transport of inclusions and mRNAs. Actin-dependent intermittent pulsations provoked high-speed back-and-forth movements of cytoplasm that may contribute to redistribution of organelles and maternal determinants. Developmental Dynamics 239:2172,2189, 2010. © 2010 Wiley-Liss, Inc. [source]

Oda16/Wdr69 is essential for axonemal dynein assembly and ciliary motility during zebrafish embryogenesis

Chunlei Gao
Abstract In the alga Chlamydomonas reinhardtii, Oda16 functions during ciliary assembly as an adaptor for intraflagellar transport of outer arm dynein. Oda16 orthologs only occur in genomes of organisms that use motile cilia; however, such cilia play multiple roles during vertebrate development and the contribution of Oda16 to their assembly remains unexplored. We demonstrate that the zebrafish Oda16 ortholog (Wdr69) is expressed in organs with motile cilia and retains a role in dynein assembly. Antisense morpholino knockdown of Wdr69 disrupts ciliary motility and results in multiple phenotypes associated with vertebrate ciliopathies. Affected cilia included those in Kupffer's vesicle, where Wdr69 plays a role in generation of asymmetric fluid flow and establishment of organ laterality, and otic vesicles, where Wdr69 is needed to develop normal numbers of otoliths. Analysis of cilium ultrastructure revealed loss of outer dynein arms in morphant embryos. These results support a remarkable level of functional conservation for Oda16/Wdr69. Developmental Dynamics 239:2190,2197, 2010. © 2010 Wiley-Liss, Inc. [source]

Network structure of projections extending from peripheral neurons in the tunic of ascidian larva

Hiroshi Q. Terakubo
Abstract In ascidian Ciona intestinalis, a subset of trunk epidermal neurons were shown to possess external network of neural projections. To characterize a more complete network in naturally hatched (chorionated) larvae, we visualized the structure with a confocal laser scanning microscope. High resolution images revealed the huge network consisting of several subnetworks in whole-larval tunic. We named this network the ASNET (ascidian dendritic network in tunic). The ASNET was dynamically generated and collapsed during larval stages. Interestingly, one of the subnetworks found around apical trunk epidermal neurons was bilaterally asymmetric. In caudal epidermal neurons, transmission electron microscopy revealed that 9+2 axonemes were accompanied by a vesicle-containing mass in the ASNET arbor, but the distal end of the arbor contained only the vesicle-containing fibrous mass and no 9+2 axonemes. The characteristics of the ASNET suggest that it forms a unique outer body network in the ascidian larval tunic. Developmental Dynamics 239:2278,2287, 2010.© 2010 Wiley-Liss, Inc. [source]

Cell type,specific expression of adenomatous polyposis coli in lung development, injury, and repair

Aimin Li
Abstract Adenomatous polyposis coli (Apc) is critical for Wnt signaling and cell migration. The current study examined Apc expression during lung development, injury, and repair. Apc was first detectable in smooth muscle layers in early lung morphogenesis, and was highly expressed in ciliated and neuroendocrine cells in the advanced stages. No Apc immunoreactivity was detected in Clara or basal cells, which function as stem/progenitor cell in adult lung. In ciliated cells, Apc is associated mainly with apical cytoplasmic domain. In response to naphthalene-induced injury, Apcpositive cells underwent squamous metaplasia, accompanied by changes in Apc subcellular distribution. In conclusion, both spatial and temporal expression of Apc is dynamically regulated during lung development and injury repair. Differential expression of Apc in progenitor vs. nonprogenitor cells suggests a functional role in cell-type specification. Subcellular localization changes of Apc in response to naphthalene injury suggest a role in cell shape and cell migration. Developmental Dynamics 239:2288,2297, 2010. © 2010 Wiley-Liss, Inc. [source]

Progressive neurogenesis defines lateralis somatotopy

Jesús Pujol-Martí
Abstract Fishes and amphibians localize hydromechanical variations along their bodies using the lateral-line sensory system. This is possible because the spatial distribution of neuromasts is represented in the hindbrain by a somatotopic organization of the lateralis afferent neurons' central projections. The mechanisms that establish lateralis somatotopy are not known. Using BAPTI and neuronal tracing in the zebrafish, we demonstrate growth anisotropy of the posterior lateralis ganglion. We characterized a new transgenic line for in vivo imaging to show that although peripheral growth-cone structure adumbrates somatotopy, the order of neurogenesis represents a more accurate predictor of the position of a neuron's central axon along the somatotopic axis in the hindbrain. We conclude that progressive neurogenesis defines lateralis somatotopy. Developmental Dynamics 239:1919,1930, 2010. © 2010 Wiley-Liss, Inc. [source]

Tankyrase is necessary for canonical Wnt signaling during kidney development

Courtney M. Karner
Abstract Recent studies using small molecule antagonists have revealed that the poly(ADP-ribose) polymerases (PARPs) Tankyrase 1 and 2 are critical regulators of canonical Wnt signaling in some cellular contexts. However, the absence of any activity during zebrafish embryogenesis suggested that the tankyrases may not be general/core components of the Wnt pathway. Here, we show that Tnks1 and 2 are broadly expressed during mouse development and are essential during kidney and lung development. In the kidney, blockage of tankyrase activity phenocopies the effect of blocking production of all Wnt ligands. Tankyrase inhibition can be rescued by activation of ,-catenin demonstrating its specificity for the Wnt pathway. In addition, treatment with tankyrase inhibitors appears to be completely reversible in some cell types. These studies suggest that the tankyrases are core components of the canonical Wnt pathway and their inhibitors should enjoy broad usage as antagonists of Wnt signaling. Developmental Dynamics 239:2014,2023, 2010 © 2010 Wiley-Liss, Inc. [source]

Jarid2 is among a set of genes differentially regulated by Nkx2.5 during outflow tract morphogenesis

Jeremy L. Barth
Abstract Nkx2.5, a transcription factor implicated in human congenital heart disease, is required for regulation of second heart field (SHF) progenitors contributing to outflow tract (OFT). Here, we define a set of genes (Lrrn1, Elovl2, Safb, Slc39a6, Khdrbs1, Hoxb4, Fez1, Ccdc117, Jarid2, Nrcam, and Enpp3) expressed in SHF containing pharyngeal arch tissue whose regulation is dependent on Nkx2.5. Further investigation shows that Jarid2, which has been implicated in OFT morphogenesis, is a direct target of Nkx2.5 regulation. Jarid2 expression was up-regulated in SHF mesoderm of Nkx2.5-deficient embryos. Chromatin immunoprecipitation analysis showed Nkx2.5 interaction with consensus binding sites in the Jarid2 promoter in pharyngeal arch cells. Finally, Jarid2 promoter activity and mRNA expression levels were down-regulated by Nkx2.5 overexpression. Given the role of Jarid2 as a regulator of early cardiac proliferation, these findings highlight Jarid2 as one of several potential mediators of the critical role played by Nkx2.5 during OFT morphogenesis. Developmental Dynamics 239:2024,2033, 2010. © 2010 Wiley-Liss, Inc. [source]

Expression of Gpr177, a Wnt trafficking regulator, in mouse embryogenesis

Hsiao-Man Ivy Yu
Abstract Wls/Evi/Srt encoding a multipass transmembrane protein has been identified as a regulator for proper sorting and secretion of Wnt in flies. We have previously demonstrated that Gpr177 is the mouse ortholog required for axis determination. Gpr177 is a transcriptional target of Wnt that is activated to assist its subcellular distribution in a feedback regulatory loop. We, therefore, proposed that reciprocal regulation of Wnt and Gpr177 is essential for the Wnt-dependent developmental and pathogenic processes. Here, we examine the expression pattern of Gpr177 in mouse development. Gpr177 is expressed in a variety of tissues and cell types during organogenesis. Furthermore, Gpr177 is a glycoprotein primarily accumulating in the Golgi apparatus in signal-producing cells. The glycosylation of Gpr177 is necessary for proper transportation in the secretory pathway. Our findings suggest that the Gpr177-mediated regulation of Wnt is crucial for organogenesis in health and disease. Developmental Dynamics 239:2102,2109, 2010. © 2010 Wiley-Liss, Inc. [source]

Mesenchymal cell remodeling during mouse secondary palate reorientation

Jiu-Zhen Jin
Abstract The formation of mammalian secondary palate requires a series of developmental events such as growth, elevation, and fusion. Despite recent advances in the field of palate development, the process of palate elevation remains poorly understood. The current consensus on palate elevation is that the distal end of the vertical palatal shelf corresponds to the medial edge of the elevated horizontal palatal shelf. We provide evidence suggesting that the prospective medial edge of the vertical palate is located toward the interior side (the side adjacent to the tongue), instead of the distal end, of the vertical palatal shelf and that the horizontal palatal axis is generated through palatal outgrowth from the side of the vertical palatal shelf rather than rotating the pre-existing vertical axis orthogonally. Because palate elevation represents a classic example of embryonic tissue re-orientation, our findings here may also shed light on the process of tissue re-orientation in general. Developmental Dynamics 239:2110,2117, 2010. © 2010 Wiley-Liss, Inc. [source]

Staying alive: Dalmatian mediated blocking of apoptosis is essential for tissue maintenance

Bilal E. Kerman
Abstract In an EMS screen for mutations disrupting tracheal development, we identified new alleles of the dalmation (dmt) gene, which had previously been shown to affect peripheral nervous system (PNS) development. Here, we demonstrate that dmt loss results in programmed cell death, disrupting PNS patterning and leading to large gaps in the salivary duct and trachea. Dmt loss results in increased expression of the proapoptotic regulator genes head involution defective (hid) and reaper (rpr), and deletion of these genes or tissue-specific expression of the baculoviral apoptotic inhibitor P35 rescues the dmt defects. dmt is also required to protect cells from irradiation induced expression of hid and rpr during the irradiation resistant stage, which begins as cells become irreversibly committed to their final fates. Thus, we propose that Dmt keeps cells alive by blocking activation of hid and rpr as cells become irreversibly committed. Developmental Dynamics 239:1609,1621, 2010. © 2010 Wiley-Liss, Inc. [source]

A novel role of CXCR4 and SDF-1 during migration of cloacal muscle precursors

Rizwan Rehimi
Abstract The cloaca acts as a common chamber into which gastrointestinal and urogenital tracts converge in lower vertebrates. The distal end of the cloaca is guarded by a ring of cloacal muscles or sphincters, the equivalent of perineal muscles in mammals. It has recently been shown that the development of the cloacal musculature depends on hindlimb muscle formation. The signaling molecules responsible for the outward migration of hindlimb myogenic precursors are not known. Based on the expression studies for CXCR4 and SDF-1, we hypothesized a role of this signaling pair during cloacal muscle precursor migration. The aim of our study was to investigate the role of SDF-1/CXCR4 during cloacal muscle precursor migration in the chicken embryos. We show that SDF-1 is expressed in the cloacal region, and by experimentally manipulating the SDF-1/CXCR4 signaling, we can show that SDF-1 guides the migration of CXCR4-expressing cloacal muscle precursors. Developmental Dynamics 239:1622,1631, 2010. © 2010 Wiley-Liss, Inc. [source]

Non-core subunit eIF3h of translation initiation factor eIF3 regulates zebrafish embryonic development

Avik Choudhuri
Abstract Eukaryotic translation initiation factor eIF3, which plays a central role in translation initiation, consists of five core subunits that are present in both the budding yeast and higher eukaryotes. However, higher eukaryotic eIF3 contains additional (non-core) subunits that are absent in the budding yeast. We investigated the role of one such non-core eIF3 subunit eIF3h, encoded by two distinct genes,eif3ha and eif3hb, as a regulator of embryonic development in zebrafish. Both eif3h genes are expressed during early embryogenesis, and display overlapping yet distinct and highly dynamic spatial expression patterns. Loss of function analysis using specific morpholino oligomers indicates that each isoform has specific as well as redundant functions during early development. The morphant phenotypes correlate with their spatial expression patterns, indicating that eif3h regulates development of the brain, heart, vasculature, and lateral line. These results indicate that the non-core subunits of eIF3 regulate specific developmental programs during vertebrate embryogenesis. Developmental Dynamics 239:1632,1644, 2010. © 2010 Wiley-Liss, Inc. [source]

Cellular dynamics of epithelial clefting during branching morphogenesis of the mouse submandibular gland

Yuichi Kadoya
Abstract We cultured the rudimental submandibular gland (SMG) of mice with a non,cell-permeable fluorescent tracer, and observed cell behavior during epithelial branching morphogenesis using confocal time-lapse microscopy. We traced movements of individual cells as shadowgraph movies. Individual epithelial cells migrated dynamically but erratically. The epithelial cleft extended by wiggling and separated a cluster of cells into two buds during branching. We examined the ultrastructure of the clefts in SMG rudiments treated with the laminin peptide A5G77f, which induces epithelial clefting. A short cytoplasmic shelf with a core of microfilaments was found at the deep end of the cleft. We propose that epithelial clefting involves a dynamic movement of cells at the base of the cleft, and the formation of a shelf within a cleft cell. The shelf might form a matrix attachment point at the base of the cleft with a core of microfilaments driving cleft elongation. Developmental Dynamics 239:1739,1747, 2010. © 2010 Wiley-Liss, Inc. [source]

Gene transfer by electroporation into hemogenic endothelium in the avian embryo

Catalina Ana Rosselló
Abstract Hematopoiesis is the dynamic process whereby blood cells are continuously produced in an organism. Blood cell production is sustained by a population of self-renewing multipotent hematopoietic stem cells (HSCs) throughout the life of an organism. Cells with definitive HSC properties appear in the mid-gestation embryo as dense clusters of cells budding from the floor of the aorta, and that of the vitelline and umbilical arteries in the aorta-gonads-mesonephros region. Attempts to genetically modify the aortic floor from which these HSCs arise have been unsuccessful in the mouse, since the regulation of gene expression in the hemogenic endothelium is largely unknown. Here we report the implementation of gene transfer by electroporation into dorsal aortic endothelial cells in the chick embryo. This approach provides a quick and reproducible method of generating gain/loss-of-function models to investigate the function of genes involved in HSC birth. Developmental Dynamics 239:1748,1754, 2010. © 2010 Wiley-Liss, Inc. [source]

Identification of germ plasm-associated transcripts by microarray analysis of Xenopus vegetal cortex RNA

Tawny N. Cuykendall
Abstract RNA localization is a common mechanism for regulating cell structure and function. Localized RNAs in Xenopus oocytes are critical for early development, including germline specification by the germ plasm. Despite the importance of these localized RNAs, only approximately 25 have been identified and fewer are functionally characterized. Using microarrays, we identified a large set of localized RNAs from the vegetal cortex. Overall, our results indicate a minimum of 275 localized RNAs in oocytes, or 2,3% of maternal transcripts, which are in general agreement with previous findings. We further validated vegetal localization for 24 candidates and further characterized three genes expressed in the germ plasm. We identified novel germ plasm expression for reticulon 3.1, exd2 (a novel exonuclease-domain encoding gene), and a putative noncoding RNA. Further analysis of these and other localized RNAs will likely identify new functions of germ plasm and facilitate the identification of cis -acting RNA localization elements. Developmental Dynamics 239:1838,1848, 2010. © 2010 Wiley-Liss, Inc. [source]

Expression of the zebrafish CD133/prominin1 genes in cellular proliferation zones in the embryonic central nervous system and sensory organs

Maura McGrail
Abstract The CD133/prominin1 gene encodes a pentamembrane glycoprotein cell surface marker that is expressed in stem cells from neuroepithelial, hematopoietic, and various organ tissues. Here we report the analysis of two zebrafish CD133/prominin1 orthologues, prominin1a and prominin1b. The expression patterns of the zebrafish prominin1a and b genes were analyzed during embryogenesis using whole mount in situ hybridization. prominin1a and b show novel complementary and overlapping patterns of expression in proliferating zones in the developing sensory organs and central nervous system. The expression patterns suggest functional conservation of the zebrafish prominin1 genes. Initial analyses of prominin1a and b in neoplastic tissue show increased expression of both genes in a subpopulation of cells in malignant peripheral nerve sheath tumors in tp53 mutants. Based on these analyses, the zebrafish prominin1 genes will be useful markers for examining proliferating cell populations in adult organs, tissues, and tumors. Developmental Dynamics 239:1849,1857, 2010. © 2010 Wiley-Liss, Inc. [source]

Signal transduction pathways that function in both development and innate immunity

Frederick A. Partridge
Abstract C. elegans is developing in importance as a model for innate immunity. Several signaling pathways are known to be required for immune responses to a diverse range of pathogens, including the insulin signaling, p38 MAP kinase and transforming growth factor-, pathways. These pathways also have roles during development, which can complicate the analysis of their functions in immunity. Recent studies have suggested that immunity in C. elegans is integrated across the organism by both paracrine and neuronal communication, showing the complexity of the immune system in this organism. Developmental Dynamics 239:1330,1336, 2010. © 2010 Wiley-Liss, Inc. [source]

Non-apoptotic cell death in Caenorhabditis elegans

Manolis Vlachos
Abstract The simple nematode worm Caenorhabditis elegans has been instrumental in deciphering the molecular mechanisms underlying apoptosis. Beyond apoptosis, several paradigms of non-apoptotic cell death, either genetically or extrinsically triggered, have also been described in C. elegans. Remarkably, non-apoptotic cell death in worms and pathological cell death in humans share numerous key features and mechanistic aspects. Such commonalities suggest that similarly to apoptosis, non-apoptotic cell death mechanisms are also conserved, and render the worm a useful organism, in which to model and dissect human pathologies. Indeed, the genetic malleability and the sophisticated molecular tools available for C. elegans have contributed decisively to advance our understanding of non-apoptotic cell death. Here, we review the literature on the various types of non-apoptotic cell death in C. elegans and discuss the implications, relevant to pathological conditions in humans. Developmental Dynamics 239:1337,1351, 2010. © 2010 Wiley-Liss, Inc. [source]

Integration of diverse inputs in the regulation of Caenorhabditis elegans DAF-16/FOXO

Jessica N. Landis
Abstract In a remarkably conserved insulin signaling pathway that is well-known for its regulation of longevity in worms, flies, and mammals, the major C. elegans effector of this pathway, DAF-16/FOXO, also modulates many other physiological processes. This raises the question of how DAF-16/FOXO chooses the correct targets to achieve the appropriate response in a particular context. Here, we review current knowledge of tissue-specificity and interacting partners that modulate DAF-16/FOXO functional output. Developmental Dynamics 239:1405,1412, 2010. © 2010 Wiley-Liss, Inc. [source]