Understanding the molecular biology of sperm calyx: biochemical and genetic analyses using Cylicin1, Cylicin1 and Calicin deficient mice

• Applicants: Dr. Simon Schneider; Professor Dr. Hubert Schorle
• Subject Area: Reproductive Medicine, Urology ; Developmental Biology ; Cell Biology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 458746826

Cylicin 1 (Cylc1) and Cylicin 2 (Cylc2) are two sperm specific proteins which have an essential role in structuring the sperm head during spermiogenesis. Loss of Cylicin leads to dose-dependent sub- or infertility due to defects in Calyx and Perinuclear Theca. Having established the mice and published the results of our experiments we next propose to identify and validate the proteins interacting with Cylicins orchestrating the Calyx and Perinuclear Theca. Using our established mouse models, we will use proteomics-based approach to identify Proteins which differ in abundance between the different genotypes. This will give us a lead into the group of proteins, which depend on and interact with Cyclicins. In parallel, we will perform Co-IP studies using a Cylc2-FLAG tagged mouse which we propose to establish. This mouse-line is required since the available custom-made antibody is not suitable for CoIP. Both sets of experiments will enable us to decipher the network of proteins which interacts with/binds to Cylicins in order to establish the calyx. Further, we managed to establish Calicin (Ccin) deficient mice. Ccin localized in the Calyx is supposed to interact with Cylicin genes. Generation of Cylc1 -/y/Ccin+/- and Cylc2+/-/Ccin+/- double heterozygous mice will allow to test whether heterozygous deletion of two different but interacting proteins leads to problems in sperm structure and affects male fertility. Knowledge of the Cylicin-interacting proteins as well as the results from the double het experiments will help in identifying male fertility patients which are collected in the MERGE consortium. Thus, the proposed experiments will not only help in understanding the various sperm specific structural proteins involved in sperm-calyx formation, but also advance our knowledge of male infertility and help to diagnose and develop of treatment regimen.

• DFG Programme: Research Grants