title: Mesodermal expression of the C. elegans HMX homolog mls-2 requires the PBC homolog CEH-20.
abstract: Metazoan development proceeds primarily through the regulated expression of genes encoding transcription factors and components of cell signaling pathways. One way to decipher the complex developmental programs is to assemble the underlying gene regulatory networks by dissecting the cis-regulatory modules that direct temporal-spatial expression of developmental genes and identify corresponding trans-regulatory factors. Here, we focus on the regulation of a HMX homoebox gene called mls-2, which functions at the intersection of a network that regulates cleavage orientation, cell proliferation and fate specification in the Caenorhabditis elegans postembryonic mesoderm. In addition to its transient expression in the postembryonic mesodermal lineage, the M lineage, mls-2 expression is detected in a subset of embryonic cells, in three pairs of head neurons and transiently in the somatic gonad. Through mutational analysis of the mls-2 promoter, we identified two elements (E1 and E2) involved in regulating the temporal-spatial expression of mls-2. In particular, we showed that one of the elements (E1) required for mls-2 expression in the M lineage contains two critical putative PBC-Hox binding sites that are evolutionarily conserved in C. briggsae and C. remanei. Furthermore, the C. elegans PBC homolog CEH-20 is required for mls-2 expression in the M lineage. Our data suggest that mls-2 might be a direct target of CEH-20 in the M lineage and that the regulation of CEH-20 on mls-2 is likely Hox-independent.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, 439 Biotechnology Building, Ithaca, NY 14853, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Herong
authors.initials: H
authors.lastname: Shi
authors.forename: Nirav M
authors.initials: NM
authors.lastname: Amin
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Sultan
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D019070:Cell Lineage; D004252:DNA Mutational Analysis; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D018398:Homeodomain Proteins; C508613:MLS-2 protein, C elegans; D014157:Transcription Factors; C418523:ceh-20 protein, C elegans