Novel heterochronic functions of the Caenorhabditis elegans period-related protein LIN-42

Dev Biol. 2006 Jan 1;289(1):30-43. doi: 10.1016/j.ydbio.2005.09.044. Epub 2005 Nov 21.


LIN-42, the Caenorhabditis elegans homolog of the Period (Per) family of circadian rhythm proteins, functions as a member of the heterochronic pathway, regulating temporal cell identities. We demonstrate that lin-42 acts broadly, timing developmental events in the gonad, vulva, and sex myoblasts, in addition to its well-established role in timing terminal differentiation of the hypodermis. In the vulva, sex myoblasts, and hypodermis, lin-42 activity prevents stage-specific cell division patterns from occurring too early. This general function of timing stage-appropriate cell division patterns is shared by the majority of heterochronic genes; their mutation temporally alters stage-specific division patterns. In contrast, lin-42 function in timing gonad morphogenesis is unique among the known heterochronic genes: inactivation of lin-42 causes the elongating gonad arms to reflex too early, a phenotype which implicates lin-42 in temporal regulation of cell migration. Three additional isoforms of lin-42 are identified that expand our view of the lin-42 locus and significantly extend the homology between LIN-42 and other PER family members. We show that, similar to PER proteins, LIN-42 has a dynamic expression pattern; its levels oscillate relative to the molts during postembryonic development. Transformation rescue studies indicate lin-42 is bipartite with respect to function. Intriguingly, the hallmark PAS domain is dispensable for LIN-42 function in transgenic animals.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Body Patterning
  • Caenorhabditis elegans / chemistry
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development*
  • Caenorhabditis elegans Proteins / analysis
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Circadian Rhythm*
  • Female
  • Gonads / growth & development*
  • Gonads / metabolism
  • Molecular Sequence Data
  • Molting
  • Mutation
  • Myoblasts / cytology
  • Myoblasts / metabolism
  • Phenotype
  • Protein Isoforms / analysis
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • RNA Interference
  • Subcutaneous Tissue / growth & development
  • Subcutaneous Tissue / metabolism
  • Transcription Factors / analysis
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Vulva / growth & development
  • Vulva / metabolism


  • Caenorhabditis elegans Proteins
  • LIN-42 protein, C elegans
  • Protein Isoforms
  • Transcription Factors