@article {73, title = {The interaction of epithelial Ihha and mesenchymal Fgf10 in zebrafish esophageal and swimbladder development.}, journal = {Dev Biol}, volume = {359}, year = {2011}, month = {2011 Nov 15}, pages = {262-76}, abstract = {

Developmental patterning and growth of the vertebrate digestive and respiratory tracts requires interactions between the epithelial endoderm and adjacent mesoderm. The esophagus is a specialized structure that connects the digestive and respiratory systems and its normal development is critical for both. Shh signaling from the epithelium regulates related aspects of mammalian and zebrafish digestive organ development and has a prominent effect on esophageal morphogenesis. The mechanisms underlying esophageal malformations, however, are poorly understood. Here, we show that zebrafish Ihha signaling from the epithelium acting in parallel, but independently of Shh, controls epithelial and mesenchymal cell proliferation and differentiation of smooth muscles and neurons in the gut and swimbladder. In zebrafish ihha mutants, the esophageal and swimbladder epithelium is dysmorphic, and expression of fgf10 in adjacent mesenchymal cells is affected. Analysis of the development of the esophagus and swimbladder in fgf10 mutant daedalus (dae) and compound dae/ihha mutants shows that the Ihha-Fgf10 regulatory interaction is realized through a signaling feedback loop between the Ihha-expressing epithelium and Fgf10-expressing mesenchyme. Disruption of this loop further affects the esophageal and swimbladder epithelium in ihha mutants, and Ihha acts in parallel to but independently of Shha in this process. These findings contribute to the understanding of epithelial-mesenchymal interactions and highlight an interaction between Hh and Fgf signaling pathways during esophagus and swimbladder development.

}, keywords = {Air Sacs, Animals, Animals, Genetically Modified, Cell Proliferation, Embryo, Nonmammalian, Epithelium, Esophagus, Female, Fibroblast Growth Factor 10, Gastrointestinal Tract, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Green Fluorescent Proteins, Hedgehog Proteins, In Situ Hybridization, Male, Membrane Proteins, Mesoderm, Microscopy, Confocal, Mutation, Protein Binding, Receptors, Cell Surface, Signal Transduction, Zebrafish, Zebrafish Proteins}, issn = {1095-564X}, doi = {10.1016/j.ydbio.2011.08.024}, author = {Korzh, Svitlana and Winata, Cecilia Lanni and Zheng, Weiling and Yang, Shulan and Yin, Ao and Ingham, Phillip and Korzh, Vladimir and Gong, Zhiyuan} } @article {69, title = {Chromatin states of developmentally-regulated genes revealed by DNA and histone methylation patterns in zebrafish embryos.}, journal = {Int J Dev Biol}, volume = {54}, year = {2010}, month = {2010}, pages = {803-13}, abstract = {

Embryo development proceeds from a cascade of gene activation and repression events controlled by epigenetic modifications of DNA and histones. Little is known about epigenetic states in the developing zebrafish, despite its importance as a model organism. We report here DNA methylation and histone modification profiles of promoters of developmentally-regulated genes (pou5f1, sox2, sox3, klf4, nnr, otx1b, nes, vasa), as well as tert and bactin2, in zebrafish embryos at the mid-late blastula transition, shortly after embryonic genome activation. We identify four classes of promoters based on the following profiles: (i) those enriched in marks of active genes (H3K9ac, H4ac, H3K4me3) without transcriptionally repressing H3K9me3 or H3K27me3; (ii) those enriched in H3K9ac, H4ac and H3K27me3, without H3K9me3; one such gene was klf4, shown by in situ hybridization to be mosaically expressed, likely accounting for the detection of both activating and repressive marks on its promoter; (iii) those enriched in H3K4me3 and H3K27me3 without acetylation; and (iv) those enriched in all histone modifications examined. Culture of embryo-derived cells under differentiation conditions leads to H3K9 and H4 deacetylation and H3K9 and H3K27 trimethylation on genes that are inactivated, yielding an epigenetic profile similar to those of fibroblasts or muscle. All promoters however retain H3K4me3, indicating an uncoupling of H3K4me3 occupancy and gene expression. All non-CpG island developmentally-regulated promoters are DNA unmethylated in embryos, but hypermethylated in fibroblasts. Our results suggest that differentially expressed embryonic genes are regulated by various patterns of histone modifications on unmethylated DNA, which create a developmentally permissive chromatin state.

}, keywords = {Animals, Blastula, Cell Line, Chromatin, Chromatin Immunoprecipitation, CpG Islands, DNA Methylation, Embryo, Nonmammalian, Fibroblasts, Gene Expression Profiling, Gene Expression Regulation, Developmental, Histones, In Situ Hybridization, Lysine, Methylation, Oligonucleotide Array Sequence Analysis, Promoter Regions, Genetic, Reverse Transcriptase Polymerase Chain Reaction, Zebrafish, Zebrafish Proteins}, issn = {1696-3547}, doi = {10.1387/ijdb.103081ll}, author = {Lindeman, Leif C and Winata, Cecilia L and Aanes, Hvard and Mathavan, Sinnakaruppan and Alestrom, Peter and Collas, Philippe} } @article {71, title = {Expression of components of Wnt and Hedgehog pathways in different tissue layers during lung development in Xenopus laevis.}, journal = {Gene Expr Patterns}, volume = {10}, year = {2010}, month = {2010 Oct-Dec}, pages = {338-44}, abstract = {

Although Wnt and Hedgehog (Hh) signaling pathways play important roles in mouse lung development, these have not been explored in the development of Xenopus lung. This may be due to the lack of specific molecular markers for different layers of tissue in Xenopus lung and/or insufficient knowledge on expression patterns of Wnt and Hh signaling components in Xenopus lung. In this study, we first described the early morphogenesis of Xenopus laevis lung by using surfactant protein C (sftpc) as a marker of lung epithelium and compared it with the expression patterns of several genes of Wnt and Hh pathways in Xenopus lungs. Our data showed that wnt7b was expressed in the entire lung epithelium from stage 37 to stage 45, while two other Wnt signaling components, wnt5a and wif1 (wnt inhibitory factor 1), were expressed in the mesenchyme layer of the entire lungs through stages 39-41. We also found that sonic hedgehog (shh) was expressed at stage 41 only in the anterior, but not in the posterior part of the lungs. These results show the expression of wnt5a, wnt7b, wif1 and shh in different layers of tissue of Xenopus lungs at early developmental stages, which implies different roles of these genes in the early development of Xenopus lungs. Our study for the first time defined specific molecular markers for description of early lung development in Xenopus, as well as provided information about expression of components of Wnt and Hh pathways in early Xenopus lungs, which should be useful for future functional studies.

}, keywords = {Animals, Epithelium, Gene Expression Regulation, Developmental, Genetic Markers, Hedgehog Proteins, In Situ Hybridization, Lung, Mesoderm, Morphogenesis, Polymerase Chain Reaction, Pulmonary Surfactants, Signal Transduction, Wnt Proteins, Xenopus Proteins, Xenopus laevis}, issn = {1872-7298}, doi = {10.1016/j.gep.2010.07.005}, author = {Yin, Ao and Winata, Cecilia L and Korzh, Svitlana and Korzh, Vladimir and Gong, Zhiyuan} }