Interacts specifically with the sex chromosomes. Expressed in adult germ cells (at protein level). Strongly expressed in adult germ cells and weakly expressed embryonic gonads (PubMed:25609838). In meiotic germ cells, begins to accumulate during the leptotene stage, before its concentration increases further during the pachytene and diplotene stages, where it localizes to the sex body (PubMed:25609838). Belongs to the HMGB family.