The Pristionchus HOX gene Ppa-lin-39 inhibits programmed cell death to specify the vulva equivalence group and is not required during vulval induction

Development. 1998 Oct;125(19):3865-73. doi: 10.1242/dev.125.19.3865.

Abstract

In the two nematode species Caenorhabditis elegans and Pristionchus pacificus the vulva equivalence group in the central body region is specified by the Hox gene lin-39. C. elegans lin-39 mutants are vulvaless and the vulval precursor cells fuse with the surrounding hypodermis, whereas in P. pacificus lin-39 mutants the vulval precursor cells die by apoptosis. Mechanistically, LIN-39 might inhibit non-vulval fate (cell fusion in C. elegans, apoptosis in P. pacificus), promote vulval fate or do both. To study the mechanism of lin-39 function, we isolated P. pacificus cell death mutants and identified mutations in ced-3. Surprisingly, P. pacificus ced-3; lin-39 double mutants form a functional vulva in the absence of LIN-39 activity. Thus, in P. pacificus lin-39 specifies the vulva equivalence group by inhibiting programmed cell death. Furthermore, these data reveal an important difference in a later function of lin-39 between the two species. In C. elegans, LIN-39 specifies vulval cell fates in response to inductive RAS signaling, and in P. pacificus LIN-39 is not required for vulval induction. Thus, the comparative analysis indicates that lin-39 has distinct functions in both species although the gene is acting in a homologous developmental system.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics*
  • Apoptosis / physiology
  • Base Sequence
  • Biological Evolution
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans Proteins*
  • Caspases*
  • Cloning, Molecular
  • Cysteine Endopeptidases / genetics
  • DNA Primers / genetics
  • DNA, Complementary / genetics
  • DNA, Helminth / genetics
  • Female
  • Genes, Helminth*
  • Genes, Homeobox*
  • Homeodomain Proteins / genetics*
  • Homeodomain Proteins / physiology
  • Male
  • Molecular Sequence Data
  • Mutation
  • Nematoda / cytology
  • Nematoda / genetics*
  • Nematoda / growth & development*
  • Phenotype
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Vulva / growth & development*

Substances

  • Caenorhabditis elegans Proteins
  • DNA Primers
  • DNA, Complementary
  • DNA, Helminth
  • Homeodomain Proteins
  • lin-39 protein, C elegans
  • Caspases
  • Cysteine Endopeptidases
  • ced-3 protein, C elegans