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Calmodulin content, Ca 2+ ‐dependent calmodulin binding proteins, and testis growth: Identification of Ca 2+ ‐dependent calmodulin binding proteins in primary spermatocytes
Author(s) -
Trejo Raquel,
Delhumeau Graciela
Publication year - 1997
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199709)48:1<127::aid-mrd15>3.0.co;2-y
Subject(s) - spermatid , calmodulin , spermatocyte , biology , prophase , meiosis , cytosol , spermatogenesis , microbiology and biotechnology , calmodulin binding proteins , sertoli cell , medicine , endocrinology , biochemistry , gene , enzyme
In contrast with the transient pre‐replicative increase in calmodulin (CaM) level observed in proliferative activated cells, postnatal development of rat testis was paralleled by 3 specific rises in CaM. The first one occurred between 5 and 10 days, coincident with the appearance and proliferation start of spermatogonia and Sertoli cells. Meiosis accomplishment and spermatid differentiation were paralleled by 2 additional rises, at 24 and 32 days, respectively. The plateau phase of testis growth was coincident with the appearance of maturating spermatids and spermatozoa in the germinal epithelium, and with a decrease in CaM content. Testicular DNA:g wet tissue ratio reached the highest level in 15‐day‐old rats and gradually decreased up to 35 days, when a constant level was reached. A similar level of Ca 2+ ‐CaMBPs was observed in 5‐ and 20‐day‐old rat testis. Although all subcellular fractions showed the ability to bind CaM in a Ca 2+ ‐dependent manner, CaM was mainly recovered in the nuclear and soluble fractions of adult and immature rat testis. Several Ca 2+ ‐CaMBPs with an apparent M r of 82, 75, 64, 19, and 14 kD were purified by affinity chromatography from pachytene primary spermatocyte nuclear matrix. Ca 2+ ‐CaMBPs showing an M r of 120, 78, 72, and 66 kD were also purified from the supernatant obtained after DNA and RNA hydrolysis of meiotic nuclei. Major cytosolic Ca 2+ ‐CaMBPs of primary spermatocytes showed an M r of 120, 84, 44, and 39 kD. The functions that these Ca 2+ ‐CaMBPs might have during the first meiotic prophase is discussed. Mol. Reprod. Dev. 48:127–136, 1997. © 1997 Wiley‐Liss, Inc.