A Role for Groucho Tetramerization in Transcriptional Repression

AUTOR(ES)

Chen, Guoqing

FONTE

American Society for Microbiology

RESUMO

The Drosophila Groucho (Gro) protein is a corepressor required by a number of DNA-binding transcriptional repressors. Comparison of Gro with its homologues in other eukaryotic organisms reveals that Gro contains, in addition to a conserved C-terminal WD repeat domain, a conserved N-terminal domain, which has previously been implicated in transcriptional repression. We determined, via a variety of hydrodynamic measurements as well as protein cross-linking, that native Gro is a tetramer in solution and that tetramerization is mediated by two putative amphipathic α-helices (termed leucine zipper-like motifs) found in the N-terminal region. Point mutations in the leucine zipper-like motifs that block tetramerization also block repression by Gro, as assayed in cultured Drosophila cells with Gal4-Gro fusion proteins. Furthermore, the heterologous tetramerization domain from p53 fully substitutes for the Gro tetramerization domain in transcriptional repression. These findings suggest that oligomerization is essential for Gro-mediated repression and that the primary function of the conserved N-terminal domain is to mediate this oligomerization.

Documentos Relacionados

• Role for Hes1-Induced Phosphorylation in Groucho-Mediated Transcriptional Repression
• Groucho Oligomerization Is Required for Repression In Vivo
• Groucho and dCtBP mediate separate pathways of transcriptional repression in the Drosophila embryo
• A role for histone deacetylase activity in HDAC1-mediated transcriptional repression
• Transcriptional repression by Pax5 (BSAP) through interaction with corepressors of the Groucho family