The amniote-conserved DNA-binding domain of CGGBP1 restricts cytosine methylation of transcription factor binding sites in proximal promoters to regulate gene expression (HTS)

Truncated forms of CGGBP1 with (N-term) or without (C-term) the DNA-binding domain (DBD) have been used to to assay global cytosine methylation. HEK293T cells with endogenous CGGBP1 knocked down were used to over-express truncated forms of CGGBP1 followed by MeDIP-Seq analysis. Genome-wide analyses of cytosine methylation and binding of CGGBP1 DBD show that CGGBP1 restricts cytosine methylation in a manner that depends on its DBD and its DNA-binding. Our findings suggest that CGGBP1 protects transcription factor binding sites (TFBS) from cytosine methylation-associated loss. A superimposition of our results and evolution of CGGBP1 suggests that mitigation of cytosine methylation is majorly achieved by its N-terminal DBD. Our results position CGGBP1 DNA-binding as a major evolutionarily acquired mechanism through which it keeps cytosine methylation under check and regulates TFBS retention.