THE YIN YANG-1 (YY1) PROTEIN UNDERGOES A DNA-REPLICATION- ASSOCIATED SWITCH IN LOCALIZATION FROM THE CYTOPLASM TO THE NUCLEUS AT THE ONSET OF S PHASE

Introduction: Vertebrate YY1 is a multifunctional protein involved in regulation of gene activity in embryonic, differentiating and non-dividing cells of all types. It functions in transcriptional activation and repression, and has recently been shown to repress embryonic gene activity via a Poly-Comb Group (PcG) mechanism (Atchinson et al., 2003). Additionally, it may function in chromatin remodeling. This transcription facto