Dynamic expression patterns of P ax6 during spermatogenesis in the mouse

Spermatogenesis is a series of complex processes to generate mature sperm, and various molecules play crucial roles in regulating these processes. Previous studies imply a possibility that a transcriptional factor P ax6, a key player of brain and sensory organ development, could be involved in spermatogenesis, but neither expression nor function of P ax6 in the adult testis has been examined yet. In the present study, we described for the first time P ax6 expression dynamics in the adult mouse testis. Using cell‐type‐specific markers, the expression of P ax6 was detected in 67.0% of promyelocytic leukemia zinc finger (Plzf)‐positive type A spermatogonia. The expression of P ax6 was also observed in p63‐positive spermatocytes and round spermatids. We did not detect any expression of P ax6 in Sox9‐positive Sertoli cells or in elongated spermatids and mature sperm. High‐resolution analyses revealed that P ax6 formed a single dot‐like structure during mid‐phase of the pachytene spermatocyte. This dot‐like structure co‐localized with γH2A.X demarcating XY body, a domain in which X and Y chromosomes are silenced and compartmentalized. These results may suggest a novel role of P ax6 in spermatogenesis.