title: The noncanonical binding site of the MED-1 GATA factor defines differentially regulated target genes in the C. elegans mesendoderm.
abstract: Mesoderm and endoderm in C. elegans arise from sister cells called MS and E, respectively. The identities of both of these mesendodermal progenitors are controlled by MED-1 and -2, members of the GATA factor family. In the E lineage, these factors activate a sequential cascade of GATA factors, beginning with their immediate targets, the endoderm-specifying end genes. We report that MED-1 binds invariant noncanonical sites in the end genes, revealing that the MEDs are atypical members of the GATA factor family that do not recognize GATA sequences. By searching the genome for clusters of these MED sites, we have identified 19 candidate MED targets. Based on their expression patterns, these define three distinct classes of MED-regulated genes: MS-specific, E-specific, and E plus MS-specific. Some MED targets encode transcription factors related to those that regulate mesendoderm development in other phyla, supporting the existence of an ancient metazoan mesendoderm gene regulatory network.
authors.affiliation: Department of Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Gina
authors.initials: G
authors.lastname: Broitman-Maduro
authors.forename: Morris F
authors.initials: MF
authors.lastname: Maduro
authors.forename: Joel H
authors.initials: JH
authors.lastname: Rothman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D019070:Cell Lineage / Q000502:physiology*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004707:Endoderm / Q000166:cytology* / Q000378:metabolism; D050980:GATA Transcription Factors; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000166:cytology* / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; C109211:END-1 protein, C elegans; D050980:GATA Transcription Factors; C433251:MED-1 protein, C elegans; C433252:MED-2 protein, C elegans; D014157:Transcription Factors