Xrcc-1 expression during male meiosis in the mouse.

XRCC1 is involved in DNA strand-break repair, homologous recombination, and sister chromatid exchange and is expressed as a low-abundance mRNA with elevated expression in testis. The purpose of this study was to determine whether specific spermatogenic cell types have elevated Xrcc-1 expression and whether expression levels change in the testis with increased age. Northern blot analysis of mRNA prepared from testes of 15-, 25-, and 60-day-old mice revealed a single hybridizing band of 2.2 kb. Quantitative RNase protection assays revealed no changes in the level of Xrcc-1 expression in testis relative to DNA content among 6-, 12-, 18-, 24-, or 28-mo-old mice. Finally, reverse transcription coupled polymerase chain reaction amplification results demonstrated that Xrcc-1 expression is most abundant in pachytene spermatocytes and round spermatids with low expression in Sertoli cells, types A and B spermatogonia, preleptotene spermatocytes, and leptotene plus zygotene spermatocytes. The relatively abundant Xrcc-1 expression in pachytene spermatocytes and round spermatids suggests that Xrcc-1 is involved in DNA strand-break repair associated with meiotic recombination in addition to its previously implicated role in strand-break repair associated with base excision repair.