Plays a critical role in transcriptional regulation and chromatin remodeling. Acts as a regulator of telomere length (PubMed:28082411, PubMed:28500257). Directly binds the telomeric double-stranded 5'-TTAGGG-3' repeat (PubMed:28082411, PubMed:28500257). Preferentially binds to telomeres that have a low concentration of shelterin complex and acts as a regulator of telomere length by initiating telomere trimming, a process that prevents the accumulation of aberrantly long telomeres (PubMed:28082411). Also acts as a transcription regulator that binds to promoter regions (PubMed:24382891, PubMed:28500257, PubMed:7969177). Regulates expression of a small subset of genes, including MTFP1 (PubMed:28500257). Acts as a negative regulator of cell proliferation by specifically activating expression of ARF, a tumor suppressor isoform of CDKN2A (PubMed:24382891). Acts as a transcription regulator of CIITA, the major factor regulating MHC class II gene expression (PubMed:39562739). In addition, regulates cellular m6A/m6Am methylation on RNA by facilitating the recruitment of the RNA demethylase, FTO, to target mRNAs (PubMed:39300486). {ECO:0000269|PubMed:24382891, ECO:0000269|PubMed:28082411, ECO:0000269|PubMed:28500257, ECO:0000269|PubMed:39300486, ECO:0000269|PubMed:39562739, ECO:0000269|PubMed:7969177}. This is the function of ZBTB48 (zinc finger and BTB domain containing 48, ENSG00000204859).