Changes in Acidic Chromatin Proteins during the Hormone-dependent Development of Rat Testis and Epididymis

• Published in: The Journal of biological chemistry 1974-10, Vol.249 (19), p.6225-6233
• Main Authors: Kadohama, Nobuyuki, Turkington, Roger W.
• Format: Article
• Language: English
• Subjects: Aging; Amino Acids - analysis; Amino Acids - metabolism; Animals; Chromatin - drug effects; Chromatin - metabolism; Chromatography, Ion Exchange; Electrophoresis, Polyacrylamide Gel; Epididymis - cytology; Epididymis - drug effects; Epididymis - growth & development; Epididymis - metabolism; Epididymis - physiology; Gonadotropins, Pituitary - pharmacology; Hydrogen-Ion Concentration; Hypophysectomy; Male; Molecular Weight; Nucleoproteins - metabolism; Nucleotides - biosynthesis; Phosphorus Radioisotopes; Pituitary Gland - physiology; Rats; Spermatozoa; Testis - cytology; Testis - drug effects; Testis - growth & development; Testis - metabolism; Testis - physiology; Testosterone - pharmacology; Tritium
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)42243-6

The acidic chromatin proteins of rat testis and epididymis have been characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in terms of their composition and relative rates of synthesis and phosphorylation in vitro. The proteins extracted from testis were resolved reproducibly into 25 specific bands. At 5 days of age, the high molecular weight Bands 1 through 5 were not detectable, but with the formation of spermatogonia and spermatocytes these bands accumulated, there was a marked increase in the rates of synthesis of Bands 1 through 9, and a marked decrease in the net rates of phosphorylation of the majority of these proteins was observed. Among the epididymal proteins, 22 specific bands were observed during development. Cell proliferation and differentiation in the epididymis at puberty were characterized by a marked decrease in Bands 1, 2, and 20, and emergence of Bands 8 through 17 as the predominant components. This process was associated with a marked increase in the rates of synthesis and a reduced net rate of phosphorylation of the majority of the epididymal acidic chromatin proteins. Changes in rates of phosphorylation in these experiments related primarily to phosphorylation of serine and threonine residues in preformed polypeptide chains, and did not reflect alterations in the specific activity of the [γ-32P]ATP pools. Developmental patterns of change in synthesis of acidic chromatin proteins in testis were found to be dependent upon pituitary gonadotropic hormones, while those of epididymis were dependent upon testosterone, as demonstrated by hormone replacement experiments with hypophysectomized rats. These results demonstrate patterns of change in formation and composition in populations of acidic chromatin proteins at well defined transitions in cell differentiation in testis and epididymis and are consistent with the hypothesis that these proteins may participate in the regulation of gene expression during the development of these organs.