In Drosophila, the Polycomb (PcG) gene family encodes chromatin proteins that are required for the repression of homeotic loci in embryonic development. PcG proteins work in conjunction with the trithorax-group (trxG), which activate homeobox gene expression during embryonic development. SCM (sex comb on midleg) is an important Drosophila PcG protein involved in transcriptional repression. SCML2 (sex comb on midleg-like 2) is a human homolog of this Drosophila protein. SCML2 is a ubiquitously expressed protein with predominant expression in placenta, testis and thymus. Upon DNA damage, SCML2 may be phosphorylated by ATR or ATM. Due to alternative splicing, two isoforms exist for this protein.
