A new ENU-induced mutant mouse with defective spermatogenesis caused by a nonsense mutation of the Syntaxin 2/Epimorphin (Stx2/ Epim) gene

Kouyou Akiyama, Shiho Akimaru, Yuka Asano, Maryam Khalaj, Chiyo Kiyosu, Ali Akbar Masoudi, Sakino Takahashi, Kentaro Katayama, Takehito Tsuji, Junko Noguchi, Tetsuo Kunieda

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Repro34 is an N-ethyl-N-nitrosourea (ENU)-induced mutation in mice showing male-specific infertility caused by defective spermatogenesis. In the present study, we investigated pathogenesis and molecular lesions in relation to spermatogenesis in the repro34/repro34 homozygous mouse. Histological examination of the testis showed that the seminiferous epithelium of the repro34/repro34 mouse contained spermatogonia and spermatocytes but no round and elongating spermatids. Instead of these haploid cells, multinucleated giant cells occupied the niche of the seminiferous tubules. Immunohistochemical staining for Hsc70t, an elongating spermatid specific protein, confirmed the absence of elongating spermatids. Furthermore, RT-PCR showed that there were significantly reduced expressions of the marker genes specifically expressed in the spermatid and that there was no difference in the expressions of the spermatocyte specific marker genes. These findings indicated interruption of the spermatogenesis during transition from the spermatocyte to spermatid in the repro34/repro34 mouse. The repro34 locus has been mapped on a 7.0-Mb region of mouse chromosome 5 containing the Syntaxin 2/Epimorphin (Stx2/Epim) gene, and targeted disruption of this gene has been reported to cause defective spermatogenesis. We therefore sequenced the entire coding region of the Stx2/Epim gene and found a nucleotide substitution that results in a nonsense mutation of this gene. The expression pattern of the Stx2/Epim gene during the first wave of spermatogenesis, increased expression at later stages of spermatogenesis, was in agreement with the affected phase of spermatogenesis in the adult repro34/repro34 testis. We therefore concluded that the male infertility of the repro34/repro34 mouse is caused by the interruption of spermatogenesis during transition from the spermatocyte to spermatid and that the nonsense mutation of the Stx2/Epim gene is responsible for the interruption of spermatogenesis.

Original languageEnglish
Pages (from-to)122-128
Number of pages7
JournalJournal of Reproduction and Development
Volume54
Issue number2
DOIs
Publication statusPublished - Apr 2008

Keywords

  • ENU mutagenesis
  • Infertility
  • Mouse
  • Mutation
  • Spermatogenesis
  • Syntaxin 2/Epimorphin (Stx2/Epim) gene

ASJC Scopus subject areas

  • Animal Science and Zoology

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