[Expression and function of CDYL-interacting protein MYH9 in mouse testis].

Objective: To identify the CDYL-interacting proteins in murine testis and investigate the mechanism of CDYL involved in spermatogenesis.

Methods: CDYL-interacting partners in testis were identified using co-immunoprecipitation coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Expression pattern of CDYL-interacting protein MYH9 was analyzed through immunohistochemistry (IHC), confocal immunofluorescence (IF) and Western blot (WB) in mouse testicular cells. The effect of the Cdyl conditional knockout (CdylcKO) in spermatogenic cell on Myh9 expression was quantified via RT-qPCR, WB and IF imaging in both spermatids and spermatozoa from cauda epididymides.

Results: Direct interaction between MYH9 and CDYL was confirmed in murine testis. During spermiogenesis, MYH9 exhibited co-localization with CDYL at the manchette structure, and binding to F-ACTIN, the component of manchette. In cauda epididymal spermatozoa, MYH9 signal concentrated on acrosomal region and continuously distributed along the tail length. Conditional deletion of Cdyl in spermatogenic cell resulted in the transcriptional downregulation of Myh9. In spermatids, CdylcKO led to reduced but retained MYH9 localization to the disorganized manchette structure. In spermatozoa from CdylcKO mice, abnormalities of MYH9 localization were observed, including attenuation of acrosomal signal and/or partial vanishment/enhancement of tail signal.

Conclusion: In murine spermatids, MYH9 protein is localized to the manchette structure, with its expression and subcellular distribution is affected by CDYL protein. CDYL-MYH9 interaction is essential for the spermiogenesis.