xnf7 functions in dorsal-ventral patterning of the Xenopus embryo.
Xenopus nuclear factor 7 (xnf7) is a maternally expressed nuclear protein that is retained in the cytoplasm from oocyte maturation until the midblastula transition (MBT). Mutations of the xnf7 phosphorylation sites to glutamic acids (dnxnf7) resulted in the retention of the endogenous protein in the cytoplasm past the MBT, indicating that cytoplasmic retention is a phosphorylation dependent process. In addition, dnxnf7 acted as a dominant negative mutant by keeping the endogenous xnf7 protein in the cytoplasm past the MBT. Overexpression of dnxnf7 in future dorsal blastomeres resulted in a ventralized or posteriorized phenotype in which the embryos lacked anterior structures, while overexpression in ventral blastomeres resulted in dorsalized embryos. dnxnf7 also affected the expression of both dorsal and ventral mesodermal markers. These data suggest that xnf7 functions in dorsal/ventral patterning and that the movement of the protein from the cytoplasm to the nucleus at the MBT is critical for the execution of a genetic program conferring a dorsal or ventral identity to the mesoderm.
El-Hodiri
H M
HM
Department of Molecular Genetics, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Shou
W
W
Etkin
L D
LD
D000818:Animals; D001692:Biological Transport; D015415:Biomarkers; D001755:Blastocyst / Q000378:metabolism*; D001757:Blastomeres; D019521:Body Patterning / Q000235:genetics*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000235:genetics; D004527:Egg Proteins; D005326:Fetal Proteins / Q000235:genetics; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins; D008648:Mesoderm / Q000737:chemistry; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010766:Phosphorylation; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D020825:T-Box Domain Proteins; D051153:Wnt Proteins; D014981:Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000098908:Brachyury Protein
D015415:Biomarkers; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D004527:Egg Proteins; D005326:Fetal Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000098908:Brachyury Protein; C094521:wnt8a protein, zebrafish; C071551:XNF7 protein, Xenopus; C054234:chordin