YY1 Protein, Human (His)

YY1, a multifunctional transcription factor, exerts both positive and negative control over a plethora of cellular and viral genes by binding to sites overlapping the transcription start site. Recognizing the consensus sequence 5'-CCGCCATNTT-3', YY1 may engage in enhanced binding with some genes that harbor a longer motif, with methylation of the initial CG dinucleotide markedly reducing binding affinity. The impact on transcriptional regulation varies based on the context in which YY1 binds, featuring diverse mechanisms such as direct activation or repression, indirect modulation through cofactor recruitment, and activation or repression via the disruption of binding sites or conformational DNA changes. YY1's activity is intricately regulated by transcription factors and cytoplasmic proteins, which can either abrogate or completely inhibit its mediated activation or repression. Notably, it acts as a repressor in the absence of adenovirus E1A protein but transforms into an activator in its presence. Collaborating with SMAD1 and SMAD4, YY1 participates in bone morphogenetic protein (BMP)-mediated cardiac-specific gene expression by binding to SMAD binding elements within BMP response elements. YY1 is implicated in development, differentiation, and proposed to recruit the PRC2/EED-EZH2 complex to target genes undergoing transcriptional repression. Furthermore, YY1 plays a role in DNA repair, exhibiting a propensity to bind to DNA recombination intermediate structures, and contributes to the regulation of enhancer activation. It is proposed as a core component of the chromatin remodeling INO80 complex, targeting this complex to YY1-responsive elements involved in transcriptional regulation, DNA replication, and potentially DNA repair.