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Functional aspects of B-Myb in early Xenopus development

Item Type:Article
Title:Functional aspects of B-Myb in early Xenopus development
Creators Name:Bouwmeester, T. and van Wijk, I. and Wedlich, D. and Pieler, T.
Abstract:The gene encoding Xenopus B-Myb (XB-Myb), a protein structurally related to the nuclear protooncogene product c-Myb, is expressed in early Xenopus embryogenesis. We report on developmental alterations in the nucleocytoplasmic distribution and phosphorylation of XB-Myb in Xenopus oocytes and embryos, as well as on a negative regulatory role of the carboxyl terminus in sequence specific DNA binding. In growing oocytes and early embryonic stages the protein is primarily located in the nucleus; in the full-grown oocyte, however, it remains sequestered in the cytoplasmic compartment. Upon meiotic maturation of the oocyte, XB-Myb becomes hyperphosphorylated. Oocyte/egg isolates of XB-Myb are inhibited in their specific DNA binding activity; truncation of the carboxyl terminal region relieves this block in nucleic acid recognition. Furthermore, we have used overexpression of XB-Myb in Xenopus embryos by means of mRNA injection as an assay for gene function in vivo. Overexpression of full-length XB-Myb, not of the carboxyl terminal deletion mutant, results in an altered morphology of lateral plate mesoderm.
Keywords:Cell Cycle Proteins, Cell Nucleus, Consensus Sequence, Cytoplasm, DNA, DNA-Binding Proteins, Immunohistochemistry, In Situ Hybridization, Meiosis, myc Genes, Nonmammalian Embryo, Oocytes, Phosphorylation, Post-Transcriptional RNA Processing, Proto-Oncogene Proteins c-myc, Trans-Activators, Transcription Factors, Western Blotting, Animals, Xenopus
Publisher:Nature Publishing Group
Page Range:1029-1038
Date:April 1994
PubMed:View item in PubMed

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