title: The function and regulation of the GATA factor ELT-2 in the C. elegans endoderm.
abstract: ELT-2 is the major regulator of genes involved in differentiation, maintenance and function of C. elegans intestine from the early embryo to mature adult. elt-2 responds to overexpression of the GATA transcription factors END-1 and END-3, which specify the intestine, as well as to overexpression of the two GATA factors that are normally involved in intestinal differentiation, ELT-7 and ELT-2 itself. Little is known about the molecular mechanisms underlying these interactions, how ELT-2 levels are maintained throughout development or how such systems respond to developmental perturbations. Here, we analyse elt-2 gene regulation through transgenic reporter assays, ELT-2 ChIP and characterisation of in vitro DNA-protein interactions. Our results indicate that elt-2 is controlled by three discrete regulatory regions conserved between C. elegans and C. briggsae that span >4 kb of 5' flanking sequence. These regions are superficially interchangeable but have quantitatively different enhancer properties, and their combined activities indicate inter-region synergies. Their regulatory activity is mediated by a small number of conserved TGATAA sites that are largely interchangeable and interact with different endodermal GATA factors with only modest differences in affinity. The redundant molecular mechanism that forms the elt-2 regulatory network is robust and flexible, as loss of end-3 halves ELT-2 levels in the early embryo but levels fully recover by the time of hatching. When ELT-2 is expressed under the control of end-1 regulatory elements, in addition to its own endogenous promoter, it can replace the complete set of endoderm-specific GATA factors: END-1, END-3, ELT-7 and (the probably non-functional) ELT-4. Thus, in addition to controlling gene expression during differentiation, ELT-2 is capable of specifying the entire C. elegans endoderm.
authors.affiliation: Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
authors.forename: Tobias
authors.initials: T
authors.lastname: Wiesenfahrt
authors.affiliation: Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
authors.forename: Janette Y
authors.initials: JY
authors.lastname: Berg
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Osborne Nishimura
authors.affiliation: Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Adam G
authors.initials: AG
authors.lastname: Robinson
authors.affiliation: Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
authors.forename: Barbara
authors.initials: B
authors.lastname: Goszczynski
authors.affiliation: Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Lieb
authors.affiliation: Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1 jmcghee@ucalgary.ca.
authors.forename: James D
authors.initials: JD
authors.lastname: McGhee
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence; D004247:DNA / Q000378:metabolism; D004707:Endoderm / Q000196:embryology* / Q000378:metabolism*; D050980:GATA Transcription Factors / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D007413:Intestinal Mucosa / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029742:Caenorhabditis elegans Proteins; C094134:ELT-2 protein, C elegans; C504457:END-3 protein, C elegans; D050980:GATA Transcription Factors; D014157:Transcription Factors; D004247:DNA
keywords: Caenorhabditis elegans; ChIP-Seq; ELT-2; Endoderm development; GATA factor; Transcription