A regulatory network of T-box genes and the even-skipped homologue vab-7 controls patterning and morphogenesis in C. elegans.
T-box genes form a large family of conserved transcription factors with diverse roles in animal development, but so far functions for only a few have been studied in detail. Here we show that four Caenorhabditis elegans T-box genes and the even-skipped-like homeobox gene vab-7 function within a regulatory network to control embryonic patterning and morphogenesis. tbx-8 and tbx-9 have functionally redundant roles in the intercalation of posterior dorsal hypodermal cells, in muscle cell positioning and in intestinal development. Inhibiting tbx-9 alone using RNA interference (RNAi) produces worms that have a thickened, 'bobbed tail' phenotype, similar to that seen in mutants of vab-7, which itself has been shown to pattern posterior muscle and hypodermal cells. In support of the view that these genes function in the same pathway, we find that tbx-8 and tbx-9 are both necessary and sufficient for vab-7 expression. In addition, a third T-box gene, tbx-30, acts to repress vab-7 expression in the anterior of embryos. We further show that vab-7 itself represses the T-box gene mab-9 in posterior cells. Thus, during posterior patterning in C. elegans, there are multiple interactions between T-box genes and the vab-7 homeobox gene. Evolutionary parallels in other organisms suggest that regulatory interactions between T-box genes and even-skipped homologues are conserved.
Pocock
Roger
R
Genetics Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
Ahringer
Julie
J
Mitsch
Michael
M
Maxwell
Sara
S
Woollard
Alison
A
D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites; D019521:Body Patterning / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000196:embryology*; D017931:DNA Primers; D004625:Embryo, Nonmammalian / Q000502:physiology; D005801:Genes, Homeobox / Q000235:genetics; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D009024:Morphogenesis / Q000502:physiology*; D016133:Polymerase Chain Reaction; D034622:RNA Interference
D017931:DNA Primers; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins