Downstream of FGF during mesoderm formation in Xenopus: The roles of Elk-1 and Egr-1 Export

@article{citeulike:5884361, abstract = {Signalling by members of the FGF family is required for induction and maintenance of the mesoderm during amphibian development. One of the downstream effectors of FGF is the SRF-interacting Ets family member Elk-1, which, after phosphorylation by MAP kinase, activates the expression of immediate–early genes. Here, we show that Xenopus Elk-1 is phosphorylated in response to FGF signalling in a dynamic pattern throughout the embryo. Loss of XElk-1 function causes reduced expression of Xbra at neurula stages, followed by a failure to form notochord and muscle and then the partial loss of trunk structures. One of the genes regulated by XElk-1 is XEgr-1 , which encodes a zinc finger transcription factor: we show that phosphorylated XElk-1 forms a complex with XSRF that binds to the XEgr-1 promoter. Superficially, Xenopus tropicalis embryos with reduced levels of XEgr-1 resemble those lacking XElk-1, but to our surprise, levels of Xbra are elevated at late gastrula stages in such embryos, and over-expression of XEgr-1 causes the down-regulation of Xbra both in whole embryos and in animal pole regions treated with activin or FGF. In contrast, the myogenic regulatory factor XMyoD is activated by XEgr-1 in a direct manner. We discuss these counterintuitive results in terms of the genetic regulatory network to which XEgr-1 contributes.}, author = {Nentwich, Oliver and Dingwell, Kevin S. and Nordheim, A. and Smith, J. C.}, citeulike-article-id = {5884361}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.ydbio.2009.09.039}, citeulike-linkout-1 = {http://linkinghub.elsevier.com/retrieve/pii/S001216060901224X}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/19799892}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=19799892}, day = {30}, doi = {10.1016/j.ydbio.2009.09.039}, issn = {00121606}, journal = {Developmental Biology}, keywords = {mapk, segmentation, xenopus}, month = {September}, posted-at = {2009-10-09 11:00:00}, priority = {2}, title = {Downstream of FGF during mesoderm formation in Xenopus: The roles of Elk-1 and Egr-1}, url = {http://dx.doi.org/10.1016/j.ydbio.2009.09.039}, year = {2009} }

TY - JOUR ID - citeulike:5884361 L3 - citeulike-article-id:5884361 N2 - Signalling by members of the FGF family is required for induction and maintenance of the mesoderm during amphibian development. One of the downstream effectors of FGF is the SRF-interacting Ets family member Elk-1, which, after phosphorylation by MAP kinase, activates the expression of immediate–early genes. Here, we show that Xenopus Elk-1 is phosphorylated in response to FGF signalling in a dynamic pattern throughout the embryo. Loss of XElk-1 function causes reduced expression of Xbra at neurula stages, followed by a failure to form notochord and muscle and then the partial loss of trunk structures. One of the genes regulated by XElk-1 is XEgr-1 , which encodes a zinc finger transcription factor: we show that phosphorylated XElk-1 forms a complex with XSRF that binds to the XEgr-1 promoter. Superficially, Xenopus tropicalis embryos with reduced levels of XEgr-1 resemble those lacking XElk-1, but to our surprise, levels of Xbra are elevated at late gastrula stages in such embryos, and over-expression of XEgr-1 causes the down-regulation of Xbra both in whole embryos and in animal pole regions treated with activin or FGF. In contrast, the myogenic regulatory factor XMyoD is activated by XEgr-1 in a direct manner. We discuss these counterintuitive results in terms of the genetic regulatory network to which XEgr-1 contributes. JF - Developmental Biology SN - 00121606 TI - Downstream of FGF during mesoderm formation in Xenopus: The roles of Elk-1 and Egr-1 KW - mapk KW - segmentation KW - xenopus AU - Nentwich, Oliver AU - Dingwell, Kevin AU - Nordheim, A AU - Smith, JC PY - 2009/09/30/ UR - http://dx.doi.org/10.1016/j.ydbio.2009.09.039 ER -