Role of translation by mitochondrial-type ribosomes during sperm capacitation: an analysis based on a proteomic approach.
Mammalian spermatozoa contain a complex population of mRNAs, some of which have been demonstrated to be translated de novo by mitochondrial-type ribosomes using D-chloramphenicol (CP), a specific inhibitor of mitochondrial translation. However, little is known about the functions of these mRNAs in mature sperm. In the present study, differential proteomic approaches were applied to study sperm protein profiles translated by mitochondrial-type ribosomes using the inhibitor CP and 44 proteins were identified with lower expression in CP-treated sperm in comparison to capacitated sperm (ratio >or= 1.5, p<0.05). Results of Western blot and real-time PCR suggest that four proteins were translated by mitochondrial-type ribosomes. Bioinformatics analysis indicated that 26 of 44 proteins were involved in some critical processes correlated to sperm-egg interaction event. In addition, Mups, whose functions in reproduction have never been studied, were chosen for further study. Our results showed that Mups proteins were localized to the acrosome and flagellum of precapacitated sperm, and were also expressed in the equatorial segment of capacitated sperm. The depletion of Mups using neutralizing antibodies significantly inhibited capacitation in a dose-dependent manner, subsequently inhibited acrosome reaction and sperm-egg fusion. In summary, mitochondrial translation during capacitation can store proteins beneficial for sperm-egg interaction.
Zhao
Chun
C
Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, PR China.
Guo
Xue-Jiang
XJ
Shi
Zhong-Hua
ZH
Wang
Fu-Qiang
FQ
Huang
Xiao-Yan
XY
Huo
Ran
R
Zhu
Hui
H
Wang
Xin-Ru
XR
Liu
Jia-Yin
JY
Zhou
Zuo-Min
ZM
Sha
Jia-Hao
JH
D000818:Animals; D015153:Blotting, Western; D002701:Chloramphenicol / Q000378:metabolism; D002875:Chromosomes; D019295:Computational Biology; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010063:Ovum / Q000502:physiology; D014176:Protein Biosynthesis; D011506:Proteins / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012270:Ribosomes / Q000235:genetics* / Q000378:metabolism; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*
D011506:Proteins; D012333:RNA, Messenger; C035737:major urinary proteins; D002701:Chloramphenicol