The Study of Genetic Variations of Human Testis-Expressed Protein 101(TEX 101) and Hormonal Levels of Fertile and Infertile (Oligospermia) Men

Abstract

Baraa Ahmed Saeed, Rayah S. Baban, Usama Al-Nasiri.

Human testis-expressed protein 101(TEX 101) play an important roles in germ cell formation during its cellular localization in the gonads through gametogenesis, signal transduction and spermatogenesis. In sexually mature testes, TEX101 protein is fundamental for production of fertile spermatozoa. This study aims to estimate the genetic variations (gene polymorphism) of TEX101 gene in fertile and infertile (oligospermia) men in Baghdad. For this purpose, two groups were included; the first include 30 infertile men (oligospermia), while the other group contained 30 fertile men. Genomic DNA was extracted from each groups and PCR-sequencing was applied to detect TEX101 gene polymorphism. The fertility hormones (Luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and prolactin) were measured for each group. Double primers were utilized to amplificate the exons 1, 2, 3, and 4 of TEX101 gene by a polymerase chain reaction (PCR) after the DNA extraction was done from blood specimens. The single nucleotide polymorphisms (SNPs) were detected through sequencing (by matching with the TEX101 gene sequencing in NCBI data bases). The results revealed five single nucleotide polymorphisms (A (516) R, T(520)W, C > S, G>T, and A>G) in chromosome 19 of TEX101 gene (exon 1,2,3, and 4) when compared with sequence ID: 83639. The variants; A (516) R and T(520)W were showed two genotypes, while other variants; C > S, G>T, and A>G showed three genotypes. In infertile (oligospermia) men, a higher significantly rise (P≤0.01) were detected in mutant genotypes (heterozygote alleles) as compared to wild genotypes (homozygote alleles) at A (516) R and T(520)W. While, in control fertile group, the wild homozygote genotypes recorded higher significantly (P≤0.01) increase in comparison with mutant homozygote genotypes. Also, the heterozygote mutant genotype (AG, TA) of variants; A (516) R and T(520)W in oligospermia infertile men presented higher significantly (P≤0.01) excess compared with mutant genotypes (heterozygote alleles) of fertile (control) men. Whereas the wild genotypes (homozygote alleles) in control appeared higher significantly (P≤0.01) raise compared with wild genotypes (AA and TT) of oligospermia infertile men. In C > S, G>T, and A>G loci, the mutant genotypes (homozygote and heterozygote alleles) recorded higher significant increment (P≤0.01) than wild homozygote genotypes in infertile (oligospermia) group. Additionally, the homozygote mutant genotypes of infertile group showed higher significant increase (P≤0.01) compared to heterozygote mutant and wild genotypes in C > S, G>T, and A>G loci. Whilst, in control fertile group, the homozygote mutant genotypes recorded higher significant rise (P≤0.01) as compared to heterozygote mutant genotypes. On the other hand, the fertile men group appeared a high significant increment (P≤0.01) in wild homozygote genotypes as compared with the wild homozygote of infertile men. In contrast, the result presented non-significant difference between fertile (control) and infertile (oligospermia) men of fertility hormones; FSH, LH, prolactin, and testosterone. As a conclusion, the gene polymorphisms in exon 1, 2, 3, and 4 influence negatively on function of TEX101 protein by reducing the signal transduction and spermatogenesis, which lead to decrease the concentration and motility of sperm.