We describe a newly discovered nuclear protein, HMGN4, that is closely rela
ted to the canonical HMGN2 nucleosome-binding protein. The protein is encod
ed by an intronless gene, which, in humans, is located in the hereditary he
machromatosis region at position 6p21.3, A single similar to2-kb HMGN4 mRNA
was found to be expressed, in variable amounts, in all human tissues teste
d; however, the HMGN4 transcript was significantly less abundant than that
of HMGN2, The HMGN4 protein could be detected in HeLa cells by Western anal
ysis with an antibody elicited against a unique region of the protein. Tran
sfection of HeLa cells with a plasmid expressing HMGN4-GFP indicated that t
he protein localizes to the nucleus. Our results expand the multiplicity of
the HMGN protein family and increase the known cellular repertoire of nucl
eosome-binding proteins.