title: The T-box factor MLS-1 acts as a molecular switch during specification of nonstriated muscle in C. elegans.
abstract: We have isolated mutations in a gene mls-1 that is required for proper specification of nonstriated muscle fates in Caenorhabditis elegans. Loss of MLS-1 activity causes uterine muscle precursors to forego their normal fates, instead differentiating as vulval muscles. We have cloned mls-1 and shown that the product is a member of the T-box family of transcriptional regulators. MLS-1 acts as a cell fate determinant in that ectopic expression can transform other cell types to uterine muscle precursors. Uterine muscle patterning is executed by regulation of MLS-1 at several different levels. The mls-1 promoter is activated by the C. elegans orthologs of Twist and Daughterless, but is only active in a subset of the lineage where these two transcription factors are present. mls-1 activity also appears to be regulated by posttranscriptional processes, as expression occurs in both uterine and vulval muscle precursors.
authors.affiliation: Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Kostas
authors.forename: Andrew
authors.initials: A
authors.lastname: Fire
mesh_terms: D000483:Alleles; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D019070:Cell Lineage; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D009130:Muscle, Smooth / Q000254:growth & development*; D009154:Mutation; D020825:T-Box Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors
chemical_list: D029742:Caenorhabditis elegans Proteins; D008164:Luminescent Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors; C447844:mls-1 protein, C elegans; D049452:Green Fluorescent Proteins