Regulation of Transcription Factor YY1 by Acetylation and Deacetylation

ABSTRACT YY1 is a sequence-specific DNA-binding transcription factor that has many important biological roles. It activates or represses many genes during cell growth and differentiation and is also required for the normal development of mammalian embryos. Previous studies have established that YY1 interacts with histone acetyltransferases p300 and CREB-binding protein (CBP) and histone deacetylase 1 (HDAC1), HDAC2, and HDAC3. Here, we present evidence that the activity of YY1 is regulated through acetylation by p300 and PCAF and through deacetylation by HDACs. YY1 was acetylated in two regions: both p300 and PCAF acetylated the central glycine-lysine-rich domain of residues 170 to 200, and PCAF also acetylated YY1 at the C-terminal DNA-binding zinc finger domain. Acetylation of the central region was required for the full transcriptional repressor activity of YY1 and targeted YY1 for active deacetylation by HDACs. However, the C-terminal region of YY1 could not be deacetylated. Rather, the acetylated C-terminal region interacted with HDACs, which resulted in stable HDAC activity associated with the YY1 protein. Finally, acetylation of the C-terminal zinc finger domain decreased the DNA-binding activity of YY1. Our findings suggest that in the natural context, YY1 activity is regulated through intricate mechanisms involving negative feedback loops, histone deacetylation, and recognition of the cognate DNA sequence affected by acetylation and deacetylation of the YY1 protein.