Zygotic expression of Exostosin1 (Ext1) is required for establishment of dorsal-ventral pattern in Xenopus

Exostosin 1 (Ext1) is a glycosyltransferase involved in the biosynthesis of the extracellular matrix Heparan Sulfate Proteoglycan (HSPG). Knockdown of Ext1 caused gastrulation defects and formation of an abnormal body axis. Since ext1 has been implicated as an indirect contributor to multiple signaling pathways in vertebrate development, microarray was used to identify genes expressed in gastrulae that would be affected by a reduction in ext1 expression. Microarray-based comparisons of gene expression in control vs. Ext1 MO embryos showed that Ext1 is involved in regulating genes that are related to metabolic process, development and signaling pathways. Half of the hits from the microarray are uncharacterized genes. Approximately forty-five percent of genes are related to metabolic process and thirty percent of genes are belonged to signaling and developmental process categories. Ten percent of each up-regulated and down-regulated gene set is predicted to function in establishment of localization by GO, which is consistent with EXT1 being involved in the movement of extracellular substances. The transcription factors or signaling protein, Isl1, Pitx2, TBX5A, Wnt5A, Wnt7A, WT1, Pax3, Wnt1, and Xbra were identified as Ext1 regulated genes. This analysis investigating the role of Ext1 during gastrulation and provide the information that EXT1 plays an important role in Xenopus early development. Exostosin 1 (EXT1) is a glycosyltransferase involved in the biosynthesis of the extracellular matrix Heparan Sulfate Proteoglycan (HSPG). Knockdown of EXT1 caused gastrulation defects and formation of an abnormal body axis. Since ext1 has been implicated as an indirect contributor to multiple signaling pathways in vertebrate development, microarray was used to identify genes expressed in gastrulae that would be affected by a reduction in ext1 expression. Microarray-based comparisons of gene expression in control vs. EXT1 MO embryos showed that EXT1 is involved in regulating genes that are related to metabolic process, development and signaling pathways. Half of the hits from the microarray are uncharacterized genes. Approximately forty-five percent of genes are related to metabolic process and thirty percent of genes are belonged to signaling and developmental process categories. Ten percent of each up-regulated and down-regulated gene set is predicted to function in establishment of localization by GO, which is consistent with EXT1 being involved in the movement of extracellular substances. The transcription factors or signaling protein, Isl1, Pitx2, TBX5A, Wnt5A, Wnt7A, WT1, Pax3, Wnt1, and Xbra were identified as EXT1 regulated genes. This analysis investigating the role of EXT1 during gastrulation and provide the information that EXT1 plays an important role in Xenopus early development.

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Shieh YE, Wells DE, Sater AK