A Xenopus tribbles orthologue is required for the progression of mitosis and for development of the nervous system.
The product of the Drosophila gene tribbles inhibits cell division in the ventral furrow of the embryo and thereby allows the normal prosecution of gastrulation. Cell division is also absent in involuting dorsal mesoderm during gastrulation in Xenopus, and to ask whether the two species employ similar mechanisms to coordinate morphogenesis and the cell cycle, we isolated a putative Xenopus homologue of tribbles which we call Xtrb2. Extensive cDNA cloning identified long and short forms of Xtrb2, termed Xtrb2-L and Xtrb2-S, respectively. Xtrb2 is expressed maternally and in mesoderm and ectoderm at blastula and gastrula stages. Later, it is expressed in dorsal neural tube, eyes, and cephalic neural crest. Time-lapse imaging of GFP-tagged Xtrb2-L suggests that during cell division, it is associated with mitotic spindles. Knockdown of Xtrb2 by antisense morpholino oligonucleotides (MOs) disrupted synchronous cell divisions during blastula stages, apparently as a result of delayed progression through mitosis and cytokinesis. At later stages, tissues expressing the highest levels of Xtrb2 were most markedly affected by morpholino knockdown, with perturbation of neural crest and eye development.
Wellcome Trust/Cancer Research UK Gurdon Institute, Department of Zoology, University of Cambridge, Cambridge CB2 1QR, UK.
Yasushi
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Saka
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D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology; D005123:Eye / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D018390:Gene Targeting; D008938:Mitosis; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology*; D009432:Neural Crest / Q000196:embryology; D016376:Oligonucleotides, Antisense / Q000235:genetics; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D029867:Xenopus Proteins / Q000235:genetics* / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics*
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D016376:Oligonucleotides, Antisense; D029867:Xenopus Proteins; C410505:trbl protein, Drosophila; D017346:Protein Serine-Threonine Kinases