CGG triplet repeat-binding protein 1 (CGGBP1) is a repetitive DNA-binding transcription regulator with target sites at CpG-rich sequences such as CGG repeats and Alu-SINEs and L1-LINEs []. CGGBP1 mitigates cytosine methylation at repetitive DNA sequences []. It also functions in DNA damage/repair and telomere metabolism []. There are indications that it may be involved in mRNA metabolism []. CGGBP1 ensures CTCF occupancy preferentially on repeats over canonical CTCF motifs, being a regulator of CTCF and its binding sites in interspersed repeats [].CGGBP1/p20 is known to bind to nonmethylated 5'-d(CGG)(n)-3' trinucleotide repeats in the in the promoter of the fragile X messenger ribonucleoprotein 1 (FMR1/FMRP) gene [, ], although it seems not to have a direct effect on FMR1 transcription [].
