P-209: Decreased Expression of Histone Acetyltransferase CDY1 Gene in Testis Tissue May Lead to Decreased Expression of Transition Protein (TNP) and Protamine (PRM) Genes,Causing Male Infertility

Background: Infertility is a complex medical problem. About 15% of couples are infertile, and male infertility being involved in roughly 50% of the cases. Among these, many cases are associated with a severe impairment of spermatogenesis. During the last stage of spermatogenesis (spermiogenesis), sperm chromatin endures complex modifications in which histones are lost and depositioned with transition proteins (TNPs) and protamines (PRMs), respectively. These processes include chromatin modifications mediated by different histone modifying enzymes resulting in compaction and protection of chromatin. A testis specific histone acetyltransferase named CDY1, which encodes a member of Chromodomain Y family of genes, causes hyperacetylation of TNP and PRM genes involved in sperm chromatin condensation. This study aimed to evaluate the relationship of CDY1 gene expression, with expression of TNP1, TNP2, PRM1 and PRM2 genes in testis tissues of subfertile men. Materials and Methods: Local ethical approval was gained for this study and informed consent was given by patients. Testicular biopsies were collected from 20 infertile men referred to Royan Institute and underwent testicular sperm extraction (TESE). Through pathological and spermogram analyses, these samples distributed into 4 groups: hypospermatogenesis (positive control), severe oligoasthenoteratozoospermia, compelete maturation arrest, and Sertoli cell only syndrome (negative control). Each group contained 5 samples. Using reverse transcription and quantitative real-time PCR (qRTPCR) methods, the expression profile of CDY1، TNP1 ،TNP2، PRM1 and PRM2 genes were evaluated. Results: The data significantly showed lower expression levels of CDY1، TNP1 ،TNP2، PRM1 and PRM2 genes in testis tissues of all four patient groups compared to positive control. Conclusion: This data demonstrated that defective expression of the histone acetyltranferase CDY1 gene, can cause to lower expression of TNP and PRM genes during spermiogenesis, leading to impairment in condensation of chromatin of sperm and subsequently male infertility.