Expression of Mitochondrial Capsule Selenoprotein mRNA Increases with Aging, but Decreases by Selenium Deficiency in the Mouse Testis

Abstract

Mitochondrial capsule selenoprotein (MCS) has been known as a structural protein of the mitochondrial sheath in spermatozoa. In this study, to investigate whether or not the expression of MCS mRNA in testes is affected by aging or selenium (Se) deficiency, the cDNA clone of MCS was isolated from the testes of 8-week-old ICR mice by reverse transcription-polymerase chain reaction. The nucleic acid sequence analysis confirmed that the cloned cDNA is an open reading frame of the MCS and contains 3 in-phase TGA codons that recognize specifically the selenocysteine in selenoprotein. According to Northern blot analysis, the MCS mRNA in testes greatly increased at 8 weeks old and then began to increase with aging. As compared with that of 8-week-old mice, the signal increased about 2.4-fold in the testes of 80-week-old mice. On the other hand, we generated Se-deficient and Se-sufficient mice by feeding weanling male mice (3 weeks old) with either a Se-deficient or a Se-sufficient diet for 11 weeks. MCS mRNA decreased about 21-fold in the testes of Se-deficient animals as compared with that of Se-sufficient animals. The present study provides a novel evidence that MCS mRNA level in testes increases with aging, but remarkably decreases due to Se deficiency.