title: Cloning, sequencing, and characterization of the murine nm23-M5 gene during mouse spermatogenesis and spermiogenesis.
abstract: Nucleoside diphosphate kinases (NDPKs) are conserved throughout evolution and have been shown to be involved in various biological phenomena. By functional screening in yeast, we identified a new member of the NDPK family, nm23-M5, which encodes a 211-amino acid protein with 86% identity to the human homolog Nm23-H5. Northern blot analysis revealed that nm23-M5 encodes two transcripts of 0.8 and 0.7kb, which are highly and specifically expressed in adult testis. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed that nm23-M5 transcripts first appear in pachytene spermatocytes and increase in abundance in subsequent stages. However, a low level of nm23-M5 mRNA was detected by RT-PCR in other tissues, such as ovary, brain, heart, and kidney. In situ hybridization studies showed that testicular nm23-M5 transcripts are localized in stage 12 to stage 16 spermatids in the neighboring lumen of seminiferous tubules. This distribution contrasts with that of Nm23-H5 transcripts, which are specifically found in spermatogonia and early spermatocytes. The heterologous expression of nm23-M5 in yeast cells confers protection from cell death induced by Bax, which is due to the generation of reactive oxygen species. Furthermore, overexpression of nm23-M5 in fibroblasts altered the cellular levels of several antioxidant enzymes, particularly glutathione peroxidase 5. Thus, we believe that the murine nm23-M5 gene plays an important role in late spermiogenesis by elevating the ability of late-stage spermatids to eliminate reactive oxygen species.
authors.affiliation: Major of Dairy Science, College of Agriculture, Gyeongsang National University, Chinju, 660-701, GyeongNam, Republic of Korea.
authors.forename: Kyu-Chan
authors.initials: KC
authors.lastname: Hwang
authors.forename: Do-Won
authors.initials: DW
authors.lastname: Ok
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Hong
authors.forename: Myeong-Ok
authors.initials: MO
authors.lastname: Kim
authors.forename: Jin-Hoi
authors.initials: JH
authors.lastname: Kim
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics*; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013087:Spermatids / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics* / Q000502:physiology; D013737:Testis / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D000975:Antioxidants; D018076:DNA, Complementary; D054778:NM23 Nucleoside Diphosphate Kinases; C517948:NME5 protein, human; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014157:Transcription Factors; C517938:NME1 protein, human; C517939:Nme1 protein, mouse; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins