title: Identification of a rat testis-specific gene encoding a potential rat outer dense fibre protein.
abstract: Screening of a rat testis expression library with an antiserum specific for an outer dense fibre (ODF) has led to the identification of a gene encoding for a putative protein previously unknown as a component of the sperm tail. This gene has been designated tpx-1 by virtue of its homology with the mouse and human gene of the same name (79 and 73%, respectively). The tpx-1-like gene encoded a 1.6-kb mRNA and a 243-amino-acid protein that had significant homology with members of the cysteine-rich secretory protein (CRISP) family and partial homology with several venom/allergen proteins from both plants and insects. During rat spermatogenesis, the tpx-1-like transcript was first detected by in situ hybridization in low levels in late pachytene spermatocytes. Low but detectable levels of expression continued up to step 5 round spermatids, after which expression levels increased dramatically to a maximum in step 11-12 spermatids. Progressively decreasing levels of expression were detected in up to step 17 elongating spermatids. Testicular somatic cells did not contain detectable tpx-1-like transcript. This pattern of expression is consistent with published data on the development of the ODF in spermatogenesis and, when taken together with a comparison of the predicted amino acid sequence of tpx-1 with the amino acid analysis of a 29-kDa rat ODF protein, suggests that the tpx-1-like gene may encode for this protein.
authors.affiliation: Institute of Reproduction and Development, Monash University, Clayton, Victoria, Australia.
authors.forename: M K
authors.initials: MK
authors.lastname: O'Bryan
authors.forename: K L
authors.initials: KL
authors.lastname: Loveland
authors.forename: D
authors.initials: D
authors.lastname: Herszfeld
authors.forename: J R
authors.initials: JR
authors.lastname: McFarlane
authors.forename: M T
authors.initials: MT
authors.lastname: Hearn
authors.forename: D M
authors.initials: DM
authors.lastname: de Kretser
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D015723:Gene Library; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: C062790:CRISP2 protein, rat; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D006023:Glycoproteins