title: Novel heterochronic functions of the Caenorhabditis elegans period-related protein LIN-42.
abstract: 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.
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, 55455, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Tennessen
authors.forename: Heather F
authors.initials: HF
authors.lastname: Gardner
authors.forename: Mandy L
authors.initials: ML
authors.lastname: Volk
authors.forename: Ann E
authors.initials: AE
authors.lastname: Rougvie
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D006066:Gonads / Q000254:growth & development* / Q000378:metabolism; D008969:Molecular Sequence Data; D018978:Molting; D009154:Mutation; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D010641:Phenotype; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D040521:Subcutaneous Tissue / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014844:Vulva / Q000254:growth & development / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C400538:LIN-42 protein, C elegans; D020033:Protein Isoforms; D014157:Transcription Factors