Restricted Expression of Ovol2/MOVO in XY Body of Mouse Spermatocytes at the Pachytene Stage

RYUSUKE CHIZAKI^*^,, IKUKO YAO^*, TAYO KATANO^*, TADASHI MATSUDA AND SEIJI ITO^*

From the ^* Department of Medical Chemistry, Kansai Medical University, Moriguchi, Japan; and the Department of Urology and Andrology, Kansai Medical University, Hirakata, Japan.

Correspondence to: Dr Seiji Ito, Department of Medical Chemistry, Kansai Medical University, 10-15 Fumizono, Moriguchi, Osaka 570-8506, Japan (e-mail: ito{at}takii.kmu.ac.jp).

Abstract

The development of multicellular organisms is controlled by sequential activation of a hierarchy of regulatory genes, which encode transcription factors having DNA-binding motifs. We previously identified a testis-specific zinc finger transcriptional factor, Ovol2/MOVO, as a mouse homologue of Drosophila Ovo. Because mice deficient in Ovol2/Movo die during early embryogenesis, its function in male germ cells has remained unknown. We have recently succeeded in preparing anti-Ovol2/MOVO antiserum for immunohistochemical use. In the present study, we demonstrated that Ovol2/MOVO protein started to be expressed in male germ cells at 2 weeks after birth and that Ovol2/MOVO expression was restricted to the XY body in spermatocytes at the pachytene stage. In a reporter assay, Ovol2/MOVO repressed the histone H1t promoter activity in the spermatogenic cell line GC-2spd. These results suggest that Ovol2/MOVO may play an important role in the XY body during spermatogenesis, possibly in the processes of XY body formation and meiotic sex chromosome inactivation.

Key words: Fertilization, gene regulation, meiosis, spermatogenesis, testis