Regulation of rnt-1 expression mediated by the opposing effects of BRO-1 and DBL-1 in the nematode Caenorhabditis elegans

Biochem Biophys Res Commun. 2008 Feb 29;367(1):130-6. doi: 10.1016/j.bbrc.2007.12.097. Epub 2007 Dec 26.

Abstract

During development of Caenorhabditis elegans, expression of the RUNX homolog, rnt-1, is tightly regulated both spatially and temporally. In this study, we investigated the mechanism underlying the temporal regulation of rnt-1. We found that rnt-1 contained evolutionarily conserved consensus RUNX binding sequences within one of its introns, and that RNT-1 bound to these intronic sequences both in vitro and in vivo in the presence of BRO-1, suggesting that RNT-1 together with BRO-1 represses its own transcription. Fine deletion and substitution experiments revealed a binding site within the intron that was critical for rnt-1 regulation. Importantly, we found that the TGFbeta homolog, DBL-1, was required for counteracting the repressive activity of BRO-1 at postembryonic stages. Accordingly, ectopic expression of DBL-1 induced transcription of rnt-1 in the lateral hypodermis and other tissues even at the postembryonic stages. Taken together, our data suggest that rnt-1 expression is regulated by the balance between DBL-1-mediated activation and BRO-1-mediated repression at the postembryonic stages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Gene Expression Regulation, Developmental / genetics
  • Gene Expression Regulation, Developmental / physiology*
  • Neuropeptides / genetics
  • Neuropeptides / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Subcutaneous Tissue / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*

Substances

  • BRO-1 protein, C elegans
  • Caenorhabditis elegans Proteins
  • Dbl-1 protein, C elegans
  • Neuropeptides
  • RNT-1 protein, C elegans
  • Repressor Proteins
  • Transcription Factors
  • Transforming Growth Factor beta