Transcriptional repressor. Binds to CArG box motifs, single-stranded and double-stranded DNA, and RNA. It may be that repression by CBF-A is a result of competitive binding of CBF, a putative positive factor, and CBF-A to the same or overlapping motifs around the CArG boxes. Identified in a IGF2BP1-dependent mRNP granule complex containing untranslated mRNAs. Interacts with APOBEC1 (By similarity). Localized in cytoplasmic mRNP granules containing untranslated mRNAs. Ubiquitous.