Hematopoietically Expressed Homeobox Protein (HHEX)

HHEX encodes a member of the homeobox family of transcription factors, many of which are involved in developmental processes. Expression in specific hematopoietic lineages suggests that this protein may play a role in hematopoietic differentiation.HHEX encodes a 270-amino acid protein that shows 75% sequence identity with the chicken protein and 97% identity with it in the homeodomain, where there are 2 consecutive proline residues. Northern blot analysis revealed expression of HHEX mRNA as a 1.7-kb transcript in myeloid cell lines but not in lymphoid cell lines or peripheral blood lymphocytes. Among nonhematopoietic cells, HHEX was found in liver cells but not in fibroblasts, placenta, or HeLa cells.