Identification of human HAPRIN potentially involved in the acrosome reaction.
The acrosome reaction in sperm is an exocytotic event required for fertilization. Previously, we isolated a novel haploid-germ-cell-specific gene in the mouse; this gene, named haprin, encodes the RING-finger, B-box-type zinc finger and coiled-coil domain (RBCC) motif protein and may be involved in the acrosome reaction. Here we report the molecular cloning and characterization of a human haprin ortholog. The deduced amino acid sequence of human haprin had 91% identity with the mouse ortholog. Transcripts of human haprin were detected exclusively in the testes. Western blot and immunocytochemical analyses detected HAPRIN protein in the testes and sperm. The protein was localized in the acrosomal region of sperm and disappeared after the acrosome reaction. Our results indicate that the function of HAPRIN is highly conserved in humans and mice and that the protein could play an important role in the regulation of the acrosome reaction.
Kitamura
Kouichi
K
Department of Science for Laboratory Animal Experimentation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Nishimura
Hiromi
H
Nishimune
Yoshitake
Y
Tanaka
Hiromitsu
H
D020101:Acrosome Reaction / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D016335:Zinc Fingers / Q000235:genetics*
D002352:Carrier Proteins