Establishment and Analysis of Cylicin1 and Cylicin2 deficient mice – a tool to study male factor infertility

点击翻译按钮获取中文摘要

The family of Cylicin-genes, Cylicin 1 (Cylc1) and Cylicin 2 (Cylc2) are found exclusively expressed in the testis. CYLC1 is detected in the calyx region of human and bovine sperm and presents as a near-equatorial belt-like and funnel shaped structure. Cylicin proteins are characterized by repetitive, lysine-rich tripeptides, which result in an overall positive charge of the protein with an isoelectric point of 10.55. Most frequent, tripeptides consist of lysine dipeptides followed by aspartic or glutamic acid (KKD/KKE). Further, CYLC1 contains a proline-rich C-terminal domain. The central part of the protein comprises several repeating units, which are predicted to form short α-helices. The function of Cylicins remains largely unknown. However, a role in sperm head shaping during spermiogenesis is discussed, since defects in perinuclear theca formation have been identified in structurally abnormal, round-headed sperm in men. Boar CYLC2 was further shown to function as an actin-binding protein, which might serve as a cytoskeletal regulator in the acrosomal region of round spermatids and the postacrosomal region of mature sperm. Recently, several infertile men were diagnosed to harbor loss of function mutations in CYLC1 indicating that Cylcins could be essential for spermatogenesis and male fertility.The project aims at further understanding the consequences of loss of Cylicin 1 and/or Cylicin 2 ratio in a comprehensive matter. We envision to develop a model of male factor infertility.• To establish and validate Cylicin 1 and Cylicin 2 deficient mouse lines.• To analyze the effects of loss of Cylicin 1 and Cylicin 2.• To breed the Cyclicin 1 mutation with the Cylicin 2 mutation to analyze redundant and compensatory effects on sperm and fertility.• To analyze the molecular effects of loss of either protein using proteomicsAnalyses will help to understand the basic biology of Cylicins and will serve as a proof of principle with regard to the human data. We will be able to generate a murine model for Cylicin-deficient male factor infertility and will be able to analyze the defects originating from the deficiency. Ultimately, the research proposed here will lay the basis to better understand infertility in man and help in development of treatment regimen.