Posterior patterning by the Caenorhabditis elegans even-skipped homolog vab-7.
Patterning of the posterior end in animals is not well understood. Homologs of Drosophila even-skipped (eve) have a similar posterior expression pattern in many animals, and in vertebrates they are linked physically to the "posterior" ends of homeotic clusters (HOM-C), suggesting a conserved role in posterior development. However, the function of this posterior expression is not known. Here I show that the Caenorhabditis elegans gene vab-7 encodes an eve homolog that is required for posterior development and expressed in a pattern strikingly similar to that of vertebrate eve genes. Using a four-dimensional recording system, I found that posterior body muscles and the posterior epidermis are patterned abnormally in vab-7 mutants, but commitment to muscle and epidermal fates is normal. Furthermore, vab-7 activity is required for the complete expression of the most posterior HOM-C gene egl-5 in muscle cells, supporting the idea that eve homologs may act with the HOM-C to determine posterior cell fates. The conservation of sequence and expression pattern between vab-7 and eve homologs in other animals argues that most eve genes have posterior mesodermal and ectodermal patterning functions.
Ahringer
J
J
Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins; D004817:Epidermis / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth / Q000502:physiology; D015801:Helminth Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D018715:Microscopy, Video; D008969:Molecular Sequence Data; D009132:Muscles / Q000196:embryology; D009154:Mutation; D018510:RNA, Helminth / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors
D001426:Bacterial Proteins; D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D015801:Helminth Proteins; D018398:Homeodomain Proteins; D018510:RNA, Helminth; D012333:RNA, Messenger; D014157:Transcription Factors; C099772:VAB-7 protein, C elegans; C052837:eve protein, Drosophila