Cloning, sequencing, and characterization of the murine nm23-M5 gene during mouse spermatogenesis and spermiogenesis.
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.
Hwang
Kyu-Chan
KC
Major of Dairy Science, College of Agriculture, Gyeongsang National University, Chinju, 660-701, GyeongNam, Republic of Korea.
Ok
Do-Won
DW
Hong
Jong-Chan
JC
Kim
Myeong-Ok
MO
Kim
Jin-Hoi
JH
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*
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