Postnatal Changes in the Calcium Binding Proteins of Mouse Testis

Abstract

To define the changes in calcium-binding proteins (CBPs) of mouse testis during postnatal development, testicular protein extracts were analyzed by mobility shift after Ca 2+ binding (MSACB) in the 2-dimensional SDS-PAGE. In the adult testis extracts, 29 kinds of protein spots showed mobility shift in the gel containing Ca 2+. Among them, 2 spots showed nonspecific mobility shift and 4 spots showed Zn 2+ shift. Drastic changes in expression of high-M r CBPs (M r > 25 kDa) were observed in testis 3 weeks after birth, suggesting that their expressions were developmentally changed. There was no obvious difference in the qualitative patterns of CBP between 4-week-old testis and adult testis. There was a large mass of CBPs (M r = 20-25 kDa) expressed constitutively in testis throughout the postnatal development. Degree of MSACB (M r on the diagonal line/M r of shifted point in Ca 2+ gel) of each spot was in the range of 1.1-1.7 in 12% acrylamide gel. These results suggest that changes in CBPs of testis are closely related with progression of spermatogenesis in mouse testis. Keywords calcium binding protein, mouse, testis Calcium plays an important role in many biological processes. Many of these events are probably mediated by interactions with a variety of calcium binding proteins (CBPs). Several CBPs in male germ cells, including sperm, were identified. These proteins include molecular chaperone involved in spermatogenesis [4], protein phosphatase [11], calmodulin [9], Ca 2+ sequestering molecule [10], antigen involved in membrane fusion of spermatozoa [13], and acrosomal component [12]. During spermatogenesis, the expression of CBPs is important for the functional differentiation of germ cells as well as general cellular process [14]. During The present study was supported by the Ministry of Public Health and Welfare of Korea (HMP-98-M-1-0017) .