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Otic Vesicle (otic + vesicle)
Selected AbstractsDan is required for normal morphogenesis and patterning in the developing chick inner earDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2007Takahiro Yamanishi During vertebrate inner ear development, compartmentalization of the auditory and vestibular apparatuses along two axes depends on the patterning of transcription factors expressed in a region-specific manner. Although most of the patterning is regulated by extrinsic signals, it is not known how Nkx5.1 and Msx1 are patterned. We focus on Dan, the founding member of the Cerberus/Dan gene family that encodes BMP antagonists, and describe its function in morphogenesis and patterning. First, we confirmed that Dan is expressed in the dorso-medial region of the otic vesicle that corresponds to the presumptive endolymphatic duct and sac (ed/es). Second, we used siRNA knockdown to demonstrate that depletion of Dan induced both a severe reduction in the size of the ed/es and moderate deformities of the semicircular canals and cochlear duct. Depletion of Dan also caused suppression of Nkx5.1 in the dorso-lateral region, suppression of Msx1 in the dorso-medial region, and ectopic induction of Nkx5.1 and Msx1 in the ventro-medial region. Most of these phenotypes also appeared following misexpression of the constitutively active form of BMP receptor type Ib. Thus, Dan is required for the normal morphogenesis of the inner ear and, by inhibiting BMP signaling, for the patterning of the transcription factors Nkx5.1 and Msx1. [source] Identification and characterization of Xenopus OMP25DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2004Masafumi Inui This study describes the isolation of mitochondrial outer membrane protein 25 (OMP25) from Xenopus laevis and an analysis of its role in early development. X. laevis OMP25 (xOMP25) is a transmembrane protein of the mitochondrial outer membrane with a PDZ domain in the cytoplasmic tail, and an approximate molecular size of 25 kDa. We isolated xOMP25 from a cDNA library of X. laevis tailbud embryos. Amino acid sequence analysis of xOMP25 showed 57% identity to mouse OMP25, with 73% identity in the PDZ domains. XOMP25 mRNA is expressed maternally, and at a constant level throughout early development. The transcript is localized to eye, otic vesicle, branchial arch and neural tube. Mitochondrial targeting of an EGFP-fusion protein of xOMP25 was visualized using a mitochondria-specific fluorescent dye. Overexpression of xOMP25 in embryos caused curved axes, small eyes and disorganized head structures. Knockdown of xOMP25 protein using antisense morpholino oligonucleotides resulted in slightly shortened axes and decreased neural tissue. Although the mechanism remains unclear, our results implicate xOMP25 protein in the formation of the intact neural tube. [source] Prdm1a is necessary for posterior pharyngeal arch development in zebrafishDEVELOPMENTAL DYNAMICS, Issue 10 2009Denise A. Birkholz Abstract Multiple tissue interactions and signaling within the pharyngeal arches are required for development of the craniofacial skeleton. Here, we focus on the role of the transcription factor prdm1a in the differentiation of the posterior skeleton. prdm1a is expressed in the presumptive pharyngeal arch region and later in an endodermal pouch, the otic vesicle, and pharyngeal teeth. prdm1a mutants display a reduction in pharyngeal arch markers, a loss of posterior ceratobranchial cartilages, and a reduction in most neural crest,derived dermal bones. This is likely caused by a decrease in the number of proliferating cells but not an increase in cell death. Finally, a reduction in two key developmental signaling pathways, Fgf and retinoic acid, alters prdm1a expression, suggesting that prdm1a expression is mediated by these signaling pathways to pattern the posterior craniofacial skeleton. Together, these results indicate an essential role for prdm1a in the development of the zebrafish craniofacial skeleton. Developmental Dynamics 238:2575,2587, 2009. © 2009 Wiley-Liss, Inc. [source] Neuronal calcium sensor-1 gene ncs-1a is essential for semicircular canal formation in zebrafish inner earDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2005Brian Blasiole Abstract We have analyzed the functional role of neuronal calcium sensor-1 (Ncs-1) in zebrafish development. We identified two orthologs of the mammalian NCS-1 gene. Full-length cDNAs encoding zebrafish Ncs-1a and Ncs-1b polypeptides were cloned and characterized. Whole-mount in situ hybridization revealed that ncs-1a mRNA was expressed beginning at early somitogenesis. As development progressed, ncs-1a mRNA was present throughout the embryo with expression detected in ventral hematopoietic mesoderm, pronephric tubules, CNS nuclei, and otic vesicle. By 4.5 days post fertilization (dpf), ncs-1a expression was detected primarily in the brain. Expression of ncs-1b mRNA was first detected at 36 hours post fertilization (hpf) and was restricted to the olfactory bulb. By 4.5 dpf, ncs-1b was expressed at low levels throughout the brain. Knockdown of ncs-1a mRNA translation with antisense morpholinos blocked formation of semicircular canals. These studies identify a novel function for ncs-1a in inner ear development and suggest that this calcium sensor plays an important role in vestibular function. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source] Zebrafish sp7:EGFP: A transgenic for studying otic vesicle formation, skeletogenesis, and bone regenerationGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 8 2010April DeLaurier Adult transgenic zebrafish expressing eGFP under the control of the zinc finger transcription factor Sp7 gene, which is expressed in osteoblasts but not chondrocytes. In this line, eGFP expression recapitulates the endogenous gene pattern of expression in the otic placode, otic vesicle and developing skeletal structures. GFP-positive cells are also observed in adult skeletal structures and in regenerating fins. This transgenic line will be a very useful tool for studying otic development and the development and regeneration of the skeleton. See the article by DeLaurier et al. in this issue. [source] Isolation and characterization of a novel Xenopus gene (xVAP019) encoding a DUF1208 domain containing proteinMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2007Xu Zhi Ruan Abstract We have identified a novel Xenopus gene (xVAP019) encoding a DUF1208 domain containing protein. Using whole-mount in situ hybridization and RT-PCR, we found abundant xVAP019 maternal transcripts in the animal hemisphere during the cleavage stages and blastula stages. During gastrulation xVAP019 is differentially expressed with higher levels in the animal helf and the highest in marginal zone, then further expressed widely at neuronal stages with strongest signals in the prospective CNS regions and the epidermal ectoderm. Subsequently xVAP019 was expressed predominantly in the head, the eyes, the otic vesicle, branchial arches, spinal cord, notochord, somites, and tailbud. It is absent or very weak in the endoderm. Injecting a morpholino oligo complementary to xVAP019 mRNA or injecting a caped xVAP019 mRNA caused most of embryos to die during gastrulation and neurulation. Overexpression of xVAP019 mRNA also led to eye defect, shorten interocular distance, small body size and abnormal pigment formation in parts of the survival embryos. Similar effects were induced by injecting the xVAP019 human homologous gene FAM92A1. Our results suggest that xVAP019 is essential for the normal ectoderm and axis mesoderm differentiation and embryos survival. This investigation is for the first time in vivo study examining the role of this novel gene and reveals an important role of xVAP019 in embryonic development. Mol. Reprod. Dev. 74: 1505,1513, 2007. © 2007 Wiley-Liss, Inc. [source] Oda16/Wdr69 is essential for axonemal dynein assembly and ciliary motility during zebrafish embryogenesisDEVELOPMENTAL DYNAMICS, Issue 8 2010Chunlei 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] Groucho corepressor proteins regulate otic vesicle outgrowthDEVELOPMENTAL DYNAMICS, Issue 3 2005Baubak Bajoghli Abstract The Groucho/Tle family of corepressor proteins is known to regulate multiple developmental pathways. Applying the dominant-negative effect of the short member Aes, we demonstrate here a critical role of this gene family also for ear development. Misexpression of Aes in medaka embryos resulted in reduced size or loss of otic vesicles, whereas overexpression of the full-length Groucho protein Tle4 gave the opposite phenotype. These results are in close agreement with phenotypes observed for eye formation, suggesting a similar role for Groucho/Tle proteins in the developmental pathways of both sensory organs. Furthermore, by using the heat-inducible HSE promoter, we observed reversible branching of the embryonic axis upon Aes misexpression, indicating a transient duplication of the organizer. Groucho proteins, therefore, are critical for organizer maintenance. Developmental Dynamics 233:760,771, 2005 © 2005 Wiley-Liss, Inc. [source] Novel metalloprotease,disintegrin, meltrin , (ADAM35), expressed in epithelial tissues during chick embryogenesisDEVELOPMENTAL DYNAMICS, Issue 3 2004Mitsuko Watabe-Uchida Abstract Members of the ADAM (adisintegrin and metalloprotease) family are involved in fertilization, morphogenesis, and pathogenesis. Their metalloprotease domains mediate limited proteolysis, including ectodomain shedding of membrane-anchored growth factors and intercellular-signaling proteins, and their disintegrin domains play regulatory roles in cell adhesion and migration. In screening for cDNAs encoding chicken ADAM proteins expressed during muscle development, we identified Meltrin , as a novel member of this family. To elucidate its functions, we investigated its expression during development by using antibodies raised against its protease domain. In the somites, Meltrin , protein was specifically expressed in the myotomal cells, which delaminate from the dermomyotome to form epithelial sheets. It was also found in the surface ectoderm, lens placodes, otic vesicles, and the gut epithelia. Basolateral localization of Meltrin , in these epithelial cells suggests its unique roles in the organization of the epithelial tissues and development of the sensory organs and the gut. Developmental Dynamics 230:557,568, 2004. © 2004 Wiley-Liss, Inc. [source] Two Na,K-ATPase ,2 subunit isoforms are differentially expressed within the central nervous system and sensory organs during zebrafish embryogenesisDEVELOPMENTAL DYNAMICS, Issue 2 2002Johannes R. Rajarao Abstract We have identified cDNAs encoding a second zebrafish ortholog of the human Na,K-ATPase ,2 subunit. The ,2b cDNA encodes a 292 amino acid-long polypeptide with 74% identity to the previously characterized zebrafish ,2a subunit. By using a zebrafish meiotic mapping panel, we determined that the ,2b gene (atp1b2b) was tightly linked to markers on linkage group 5, whereas the ,2a gene was located on linkage group 23. In situ hybridization analysis shows that in developing zebrafish embryos, atp1b2a and atp1b2b are predominantly expressed in the nervous system. ,2a transcripts were abundantly expressed throughout brain as well as spinal cord neurons and lateral line ganglia. In contrast, ,2b mRNA expression was primarily detected in sensory organs, including retina, otic vesicles, and lateral line neuromast cells. These results suggest that the ,2a and ,2b genes play distinct roles in developing brain and sensory organs, and raise the possibility that the functions encoded by the single mammalian ,2 gene may be partitioned between the two zebrafish ,2 orthologs. © 2002 Wiley-Liss, Inc. [source] Tissue-specific expression of Cre recombinase from the Tgfb3 locusGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 2 2008Liang-Tung Yang Abstract Tgfb3, a member of the TGF-, superfamily, is tightly regulated, both spatially and temporally, during embryogenesis. Previous mouse knockout studies have demonstrated that Tgfb3 is absolutely required for normal palatal fusion and pulmonary development. We have generated a novel tool to ablate genes in Tgfb3 -expressing cells by targeting the promoterless Cre-pgk-Neo cassette into exon 1 of the mouse Tgfb3 gene, which generates a functionally null Tgfb3 allele. Using the Rosa26 reporter assay, we demonstrate that Cre -induced recombination was already induced at embryonal day 10 (E10) in the ventricular myocardium, limb buds, and otic vesicles. At E14, robust recombination was detected in the prefusion palatal epithelium. Deletion of the TGF-, type I receptor Alk5 (Tgfbr1) specifically in Tgfb3 expressing cells using the Tgfb3-Cre driver line lead to a cleft palate phenotype similar to that seen in conventional Tgfb3 null mutants. In addition, Alk5/ Tgfb3-Cre mice displayed hydrocephalus, and severe intracranial bleeding due to germinal matrix hemorrhage. genesis 46:112,118, 2008. © 2008 Wiley-Liss, Inc. [source] Expression of p27BBP/eIF6 is highly modulated during Xenopus laevis embryogenesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2006Maria Carmela Vaccaro Abstract Protein p27BBP/eIF6 is necessary for ribosomal function of all cells. Previous data showed that from mammals to yeast p27BBP/eIF6 is involved in the biogenesis of ribosomal subunit 60S and its association with the 60S prevents premature 80S formation regulated by PKC signaling, indicating that phosphorylation of p27BBP/eIF6 is needed for translation to occur. While in vitro p27BBP/eIF6 is constitutively expressed, and it has a high level of expression in cycling cells, in vivo its expression varies according to tissues and appears regulated by factors up to now unknown. p27BBP/eIF6 has never been investigated in developing organisms where its upregulation can be correlated with tissue growth and differentiation. In this study we have sequenced p27BBP/eIF6 cDNA and studied its expression during development of Xenopus laevis, as the first step for studying its regulation. The amino acid sequence is highly conserved with two putative PKC phosphorylation sites in serine, one site being typical of Xenopus. At the end of gastrulation, the p27BBP/eIF6 riboprobe localizes in the neural plate and in the paraxial mesoderm. In particular, from stage 24, a clear-cut localization occurs in the perspective head. In embryos exposed to teratogens, the localization of p27BBP/eIF6 riboprobe varies according to the change of head size caused by the treatment. p27BBP/eIF6 expression is particularly evident in differentiating olfactory pits, the lens, otic vesicles, and in branchial arches. Features of particular interest are p27BBP/eIF6 high level of expression in the eye field, and in the mid-hindbrain-boundary, two regions with high proliferative activity. Altogether, data indicate that a modulated expression of p27BBP/eIF6 occurs in developing anlagens in addition to a basal level of expression, and may suggest a correlation between p27BBP/eIF6 and proliferative activity. Moreover, the X. laevis cDNA isolation and characterization offer new hints for further studies in relation to potential p27BBP/eIF6 phosphorylation. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] | ||||||||||