Identification of a Novel Testis-Specific Leucine-Rich Protein in Humans and Mice

• Published in: Biology of reproduction Vol. 62; no. 5; pp. 1278 - 1284
• Main Authors: Xue, J C, Goldberg, E
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Reproduction 01-05-2000
• Subjects: Amino Acid Sequence; Animals; Blotting, Western; Cloning, Molecular; Female; Gene Expression Regulation, Developmental; Humans; Male; Meiosis; Mice; Mice, Inbred Strains; Molecular Sequence Data; Neuropeptides - chemistry; Nuclear Proteins - chemistry; Organ Specificity; Proteins - analysis; Proteins - genetics; Proteins - metabolism; Seminiferous Tubules - physiology; Sequence Homology, Amino Acid; Testis - chemistry; Testis - metabolism
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod62.5.1278

A novel testis-specific protein, termed LRTP, was identified by screening both human and mouse testis and mouse pachytene
spermatocyte cDNA libraries. Sequence analyses (GenBank accession number: AF092208) revealed that LRTP contains an amino terminus
leucine-rich repeat domain. There are several acidic regions rich in glutamic acid in the C-terminus. The sequence, by GenBank
search, shows similarities to LANP and SDS22+, leucine-rich repeat proteins localized to the nucleus and involved in the regulation
of protein phosphatases. In mouse, the mRNA is first detected at about Day 14 postpartum, presumably when mid-pachytene spermatocytes
are first seen. In situ hybridization confirmed the expression of the LRTP mRNA at this stage of spermatogenesis. Immunohistochemical
analysis revealed that the protein is most abundant in the cytoplasm of pachytene and diplotene cells, corresponding to late
prophase of meiosis I. Immunohistochemical localization is markedly reduced in secondary spermatocytes, suggesting a functional
association of LRTP with meiosis. An LRTP cDNA probe did not bind to mouse ovary RNA in a dot blot assay.