Asthenozoospermic buffalo (Bubalus bubalis) sperm tail is associated with lower expression of tektin-2 and Spag6 and higher expression of specific tyrosine phosphorylated proteins.

Abstract

Study of motility-associated proteins is a direct approach to decode the underlying mechanisms of the motility-regulation pathway in a mammalian spermatozoon. In this aspect, attempts were made to characterize and study the expression pattern of two candidate motility-associated proteins of mammalian sperm such as Tektin-2 and SPAG6 and post-translationally modified tyrosine phosphorylated proteins between the two defined groups of buffaloes: normozoospermic (NS) and asthenozoospermic (AS). 1-D Western blot demonstrated three Tektin-2 immunoreactive bands (95.3, 55.7 and 33.0 kDa) in buffalo sperm tails. Of these, the intensity of 95.3 kDa band reduced significantly (P ≤ 0.05) in sperm tail of AS group as compared to that of NS group. Similarly, the sperm tail demonstrated a single SPAG6-immnunoreactive band of 31.6 kDa that reduced significantly (P ≤ 0.05) in sperm tail of AS group as compared to that of NS group. Both AS and NS group sperm tail demonstrated at least five tyrosine phosphorylated proteins (89.5, 53.3, 44.5, 30.9 and 16.7 kDa). Of these, the intensity of 44.5 kDa band was significantly higher (P ≤ 0.05) in AS group as compared to that of NS group. Interestingly, within the AS group, degree of expression of 53.3 kDa tyrosine phosphorylated protein was bull-specific. The findings of the present study have demonstrated that AS group of buffalo bulls are associated with lower expression of Tektin-2 and SPAG6 and higher expression of specific tyrosine phosphorylated proteins.