title: Novel testis-expressed profilin IV associated with acrosome biogenesis and spermatid elongation.
abstract: A novel profilin, named profilin IV, was cloned and characterized as a testicular isoform, distinct from the previously described testis-specific profilin III. Profilin IV showed only 30% amino acid identity with the other mammalian profilins; nevertheless, database searches produced significant alignments with the conserved profilin domain. Northern blot analysis and in situ transcript hybridization suggested that profilin IV, like profilin III, is transcribed in the germ cells. However, the timing of their expression during post-natal development of rat testis and in the rat spermatogenetic cycle was distinct. In the human testis, profilin IV mRNA expression correlates with the presence of germ cells suggesting that it may be a suitable molecular diagnostic parameter to supplement conventional histopathological diagnostics in the assessment of testicular biopsies. The predicted profilin IV protein was verified employing an anti-oligopeptide antibody. Western blot analysis detected an immunorelated testicular protein of approximately 14 kDa. Immunohistochemistry revealed an intracellular protein of the rat, the mouse and the human testis accumulating asymmetrically in the cytoplasm of round and elongating spermatids with its perinuclear location coinciding with the position of the developing acrosome-acroplaxome and the manchette. Profilin IV thus may regulate testicular actin cytoskeleton dynamics and play a role in acrosome generation and spermatid nuclear shaping.
authors.affiliation: Department of Andrology, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany. kirchhoff@ihf.de
authors.forename: Heike
authors.initials: H
authors.lastname: Obermann
authors.forename: Inka
authors.initials: I
authors.lastname: Raabe
authors.forename: Marga
authors.initials: M
authors.lastname: Balvers
authors.forename: Bärbel
authors.initials: B
authors.lastname: Brunswig
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schulze
authors.forename: Christiane
authors.initials: C
authors.lastname: Kirchhoff
mesh_terms: D000177:Acrosome / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003285:Contractile Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008297:Male; D051379:Mice; D008840:Microfilament Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D051304:Profilins; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D013087:Spermatids / Q000166:cytology / Q000378:metabolism*; D013091:Spermatogenesis; D013737:Testis / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism
chemical_list: D003285:Contractile Proteins; D008840:Microfilament Proteins; C495738:PFN1 protein, human; C495739:Pfn1 protein, mouse; C495740:Pfn1 protein, rat; D051304:Profilins; D012333:RNA, Messenger