Journal of Andrology, Vol. 26, No. 4, July/August 2005
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.04189
Identification of Human HAPRIN Potentially Involved in the Acrosome Reaction
KOUICHI KITAMURA*,
HIROMI NISHIMURA,
YOSHITAKE NISHIMUNE AND
HIROMITSU TANAKA
From the Department of Science for Laboratory Animal Experimentation,
Research Institute for Microbial Disease, Osaka University, Osaka,
Japan.
*
Present address: Department of Development and Differentiation, Institute for
Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho Shogoin,
Sakyo-ku, Kyoto, 606-8507, Japan.
|
Correspondence to: Dr Hiromitsu Tanaka, Research Institute for Microbial
Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
(e-mail:
tanaka{at}biken.osaka-u.ac.jp). |
The acrosome reaction in sperm is an exocytotic event required for
fertilization. Previously, we isolated a novel
haploidgerm-cellspecific gene in the mouse; this gene, named
haprin, encodes the RING-finger, B-boxtype 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.
Key words: Sperm, spermatozoa, vesicle, RBCC protein
Copyright © 2005 by The American Society of Andrology.