Modulation of YY1 activity by SAP30

Abstract

Yin Yang 1 (YY1) is a highly conserved and multifunctional transcription factor. The diverse activities of YY1 are regulated and sometimes modified by interaction with various other proteins. By using a yeast two-hybrid screening system, SAP30 was identified as a protein that associates with YY1 and it is able to enhance YY1-mediated repression in a dose-dependent manner. SAP30 is a 30kDa nuclear protein and is a component of the human histone deacetylase complex. In this study, the interaction of SAP30 and YY1 was confirmed both by in vitro and in vivo assays. The interaction domains between YY1 and SAP30 were mapped to the C-terminal segment of YY1 (295-414) and the C-terminal 91 amino acid region of SAP30. The observation that YY1, SAP30, and HDAC1 form a complex in vivo provides evidence that YY1 also recruits HDAC1 indirectly via its binding to SAP30. These results describe a novel mechanism for YY1-mediated repression.