title: The temporally regulated transcription factor sel-7 controls developmental timing in C. elegans.
abstract: The temporal sequence of cell division and differentiation is explicitly controlled for succession and synchrony of developmental events. In this study we describe how the Caenorhabditis elegans gene sel-7 specifies the L3 stage-specific fate of seam cells, which adopt temporal specificities at each of four larval stages. Loss of function of sel-7 causes reiteration of the L2 stage fate at the L3 stage. sel-7 is involved in regulating the temporal expression pattern of hbl-1, which is a key factor in specifying the L2/L3 progression. We also show that sel-7 functions redundantly with other retarded heterochronic genes, including lin-46, daf-12 and the let-7 family miRNAs, in preventing adoption of the L2 fate at later stages. Expression of sel-7 in seam cells is temporally regulated through an evolutionarily conserved regulatory element located in intron 4 of sel-7. We further demonstrate that reiteration of the L2 proliferative seam cell division at the L3 stage in sel-7 mutants requires activity of the transcriptional mediator complex. Our study reveals that sel-7 functions as a novel heterochronic gene in controlling temporal cell identities and also demonstrates a role of the transcriptional mediator complex in integrating temporal information to specify seam cell division patterns in C. elegans.
authors.affiliation: National Institute of Biological Sciences, Zhongguancun Life Science Park, Beijing, PR China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xia
authors.forename: Xinxin
authors.initials: X
authors.lastname: Huang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D019070:Cell Lineage; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D007438:Introns; D009154:Mutation; D009687:Nuclear Proteins; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C543329:Sel-7 protein, C elegans; D014157:Transcription Factors