Acts as a key transcription regulator of histones (PubMed:25339177, PubMed:40516528, PubMed:40516529). Activates transcription of the histone H2A, histone H2B, histone H3 and histone H4 genes in conjunction with GON4L and MIZF (PubMed:25339177). Together with CRAMP1, binds to the promoters of H1 genes (H1-2, H1-3, H1-4, H1-5 and H1-10/H1x), driving their transcription (PubMed:40516528, PubMed:40516529). Also acts as a transcription corepressor, as part of a complex with YY1, SIN3A and HDAC1 (By similarity). Required for B- cell lymphopoiesis (By similarity). {ECO:0000250|UniProtKB:Q9DB00, ECO:0000269|PubMed:25339177, ECO:0000269|PubMed:40516528, ECO:0000269|PubMed:40516529}. This is the function of Ensembl gene identifier ENSG00000116580 (GON4L, gon-4 like).