title: Characterization of 3-hydroxyisobutyrate dehydrogenase, HIBADH, as a sperm-motility marker.
abstract: OBJECTIVE
  Asthenozoospermia is a major cause of male infertility. However, the molecular mechanisms underlying sperm-motility defects remain largely unknown in the majority of cases. In our previous study, we applied a proteomic approach to identify unknown proteins that were downregulated in spermatozoa with low motility compared to spermatozoa with good motility. Several sperm motility- related proteins have been identified. In this study, 3-hydroxyisobutyrate dehydrogenase (HIBADH), one of the proteins identified using the proteomic tools, is further characterized.
  
  
  METHODS
  Reverse-transcription polymerase chain reactions (RT-PCR), western blotting, and immunofluorescence assays (IFA) were preformed to investigate the expression pattern. The enzymatic activity of HIBADH was evaluated in sperm with good (>50 %), moderate (< 50 %) and lower motility (< 20 %).
  
  
  RESULTS
  Using RT-PCR, we found that transcripts of HIBADH are enriched in the cerebellum, heart, skeletal muscle, uterus, placenta, and testes of male humans. In western blotting, it is expressed in the placenta, testes, and spermatozoa. During spermiogenesis, HIBADH is located at the mid-piece (a specialized development from the mitochondria) of elongating, elongated, and mature sperm. The enzymatic activity of HIBADH in sperm with moderate and lower motility were significantly reduced compared with good motility (P<0.0001 and P<0.05, respectively).
  
  
  CONCLUSIONS
  Our study indicated that HIBADH is involved in the mitochondrial function of spermatozoa, and maintains sperm motility. It may serve as a sperm-motility marker.
authors: Department of Obstetrics and Gynecology, Chi-Mei Medical Center, Tainan, Taiwan.
authors: Yung-Chieh
authors: YC
authors: Tasi
authors: Hsin-Chih Albert
authors: HC
authors: Chao
authors: Chia-Ling
authors: CL
authors: Chung
authors: Xiu-Ying
authors: XY
authors: Liu
authors: Ying-Ming
authors: YM
authors: Lin
authors: Pao-Chi
authors: PC
authors: Liao
authors: Hsien-An
authors: HA
authors: Pan
authors: Han-Sun
authors: HS
authors: Chiang
authors: Pao-Lin
authors: PL
authors: Kuo
authors: Ying-Hung
authors: YH
authors: Lin
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D053627:Asthenozoospermia / Q000201:enzymology; D015415:Biomarkers / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013081:Sperm Motility; D013091:Spermatogenesis; D013094:Spermatozoa / Q000201:enzymology*
chemical_list: D015415:Biomarkers; D000429:Alcohol Oxidoreductases; C021398:3-hydroxyisobutyrate dehydrogenase