A cell-specific enhancer that specifies lin-3 expression in the C. elegans anchor cell for vulval development.
During C. elegans vulval development, the anchor cell (AC) in the somatic gonad expresses lin-3, activating the EGF receptor signaling pathway in vulval precursor cells (VPCs) and thereby inducing and patterning VPCs. Previous studies with lin-3 mutants and transgene expression have revealed that the level of LIN-3 in the AC must be precisely regulated for proper vulval development. To understand how lin-3 expression is achieved in the AC, we identified a 59 bp lin-3 enhancer sufficient to activate lin-3 transcription solely in the AC. The enhancer contains two E-box elements, and one FTZ-F1 nuclear hormone receptor (NHR) binding site that is mutated in a vulvaless mutant, lin-3(e1417). Mutagenesis studies show that both E-boxes and the NHR binding site are necessary to express lin-3 in the AC. In vitro DNA-binding studies and in vivo functional assays indicate that distinct trans-acting factors, including the E-protein/Daughterless homolog HLH-2 and unidentified nuclear hormone receptor(s), are necessary for lin-3 transcription in the AC and thus are involved in vulval development.
Hwang
Byung Joon
BJ
Howard Hughes Medical Institute and Division of Biology, 156-29 California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
Sternberg
Paul W
PW
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D017124:Conserved Sequence; D004625:Embryo, Nonmammalian / Q000502:physiology; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D004815:Epidermal Growth Factor / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D016678:Genome; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D014158:Transcription, Genetic; D014844:Vulva / Q000196:embryology*
D029742:Caenorhabditis elegans Proteins; D018160:Receptors, Cytoplasmic and Nuclear; C075912:Lin-3 protein, C elegans; D004815:Epidermal Growth Factor