Differential proteins associated with plasma membrane in X- and/or Y-chromosome bearing spermatozoa in indicus cattle

The differential proteins associated with plasma membrane of spermatozoa are less known, identification of which shall help overcome limitations of currently used methods of sperm sexing, considered as a high priority for livestock sector of many countries. This study has reported plasma membrane proteomics of unsorted spermatozoa and differential expression of plasma membrane associated proteins between X- and Y- chromosome bearing spermatozoa of indicus cattle (Bos indicus). Isolation of plasma membrane fraction using percoll gradient, relatively a rapid method, from bovine spermatozoa has been reported to enrich isolation of plasma membrane proteins. Significant enrichment for plasma membrane associated proteins was observed in plasma membrane fraction (P < 0.05) as compared to the total cell lysate using LC-MS/MS. Furthermore, these experiments were conducted in flow cytometry sorted, sexed-semen samples. Thirteen proteins were identified as differentially abundant between X- and Y- sorted spermatozoa. Among these, two proteins were down regulated in Y- sorted spermatozoa compared to the X- sorted spermatozoa (P < 0.05), while four and seven proteins could be noted in X- and Y- sorted spermatozoa, respectively. Proteins that are presumed to support sperm capacitation and sperm migration velocity were found to be abundant in Y- sorted spermatozoa while those associated with structural molecule activity were identified as abundant in X- sorted spermatozoa in the present study. Our study provides better insight into the plasma membrane proteomics of spermatozoa of indicus cattle and furnishes data that might aid in design and development of alternate and open technology for sex-sorting of semen.