Outer Dense Fiber Protein 4, Sperm Tails (ODF4)

Oppo1 (Odf4),encodes a protein localized to the outer dense fibers of the mature sperm tail. Using a human EST with sequence homology to mouse Odf4, Kitamura et al. (2003) isolated human ODF4 cDNA from a testis cDNA library and ODF4 genomic clones from whole blood. The deduced 257-amino acid ODF4 protein shares 39.9% identity with the mouse protein.Immunofluorescence staining of ejaculated sperm localized ODF4 to a restricted region from the neck to the middle and principal pieces of sperm flagellae.ODF4 gene contains 3 exons and differs from the 5-exon structure of the mouse gene; most notably, ODF4 exon 1 extends over mouse exons 1 and 2, and the ODF4 gene lacks an exon corresponding to exon 3 of the mouse gene.