Genetic Variation in the Testis-Specific GSG3/CAPZA3 Gene Encoding for the Actin Regulatory Protein in Infertile Males

The actin capping protein GSG3/CAPZA3 plays a physiologically important role in maintaining sperm architecture for fertilization. The GSG3/CAPZA3 gene is conserved in mammals and lacks introns. A missense mutation in the CAPZA3 gene in mice causes male infertility by reducing the concentration and changing the shape of sperm. To investigate possible associations between GSG3/CAPZA3 gene variations and impaired spermatogenesis in Japanese males, we screened for mutations in GSG3/CAPZA3 using DNA from 261 sterile male patients and 139 male volunteers who were fertile. A single nucleotide polymorphism(SNP)was found in one sample in the heterozygous state in the fertile male volunteers. The results indicate that compared with other germ-cell-specific intronless genes the change was restricted in GSG3/CAPZA3 protein.