Alternative titles; symbols
HGNC Approved Gene Symbol: SPAG8
Cytogenetic location: 9p13.3 Genomic coordinates (GRCh38): 9:35,807,785-35,812,262 (from NCBI)
Antibodies to sperm plasma membrane antigens, such as SMP1, impair sperm function and have been found in a subset of infertile couples as well as in many vasectomized men in whom infertility has persisted after vasectomy reversal (summary by Liu et al., 1996).
By screening testis cDNA libraries with a probe identified through immunoscreening with antibodies from an infertile female patient (Miao et al., 1995), followed by 5-prime and 3-prime RACE, Liu et al. (1996) obtained a full-length cDNA encoding SPAG8, which they termed SMP1. Sequence analysis predicted that the 523-amino acid type II transmembrane protein lacks a signal peptide but contains hydrophobic regions near the N and C termini that may function as transmembrane domains. Northern blot analysis detected a 2.45-kb transcript in testis. RT-PCR analysis revealed expression in testis but not in liver or kidney. Western blot analysis showed expression of a 55.5-kD protein, which is very similar to the predicted size. Immunofluorescence microscopy demonstrated expression in the acrosome of the sperm head.
Using immunocytochemistry, Miao et al. (1995) found expression of SPAG8, which they called BS84 (84-kD Beijing sperm), in testis but not in brain, liver, or kidney. RNA dot blot hybridization analysis detected expression in testis but not in heart, brain, lung, or kidney. Autoradiographic analysis detected transcripts in spermatogonia, spermatocytes, and spermatid of seminiferous epithelium.
By radiation hybrid and FISH analyses, Wang et al. (1999) mapped the SPAG8 gene to chromosome 9p13-p12.
Liu, Q.-Y., Wang, L. F., Miao, S. Y., Catterall, J. F. Expression and characterization of a novel human sperm membrane protein. Biol. Reprod. 54: 323-330, 1996. [PubMed: 8788182] [Full Text: https://doi.org/10.1095/biolreprod54.2.323]
Miao, S., Yan, Y., Li, Y., Bai, Y., Wei, S., Zong, C., Zhao, M., Zong, S., Wang, L. cDNA encoding a human sperm membrane protein BS-84. Prog. Natural Sci. 5: 119-122, 1995.
Wang, H., Miao, S., Chen, D., Wang, L., Koide, S. S. Assignment of chromosomal locus and evidence for alternatively spliced mRNAs of a human sperm membrane protein (hSMP-1). Biochim. Biophys. Acta 1447: 119-124, 1999. [PubMed: 10500252] [Full Text: https://doi.org/10.1016/s0167-4781(99)00136-0]