Mouse sperm lacking ADAM1b/ADAM2 fertilin can fuse with the egg plasma membrane and effect fertilization.
Fertilin, a heterodimeric protein complex composed of alpha (ADAM1) and beta (ADAM2) subunits on the sperm surface, is believed to mediate adhesion and fusion between the sperm and egg plasma membranes. Here we have shown that mutant male mice lacking ADAM1b are fertile and that the loss of ADAM1b results in no significant defect in sperm functions such as migration from the uterus into oviduct, binding to egg zona pellucida, and fusion with zona pellucida-free eggs. ADAM1b-deficient epididymal sperm showed a severe reduction of ADAM2 on the cell surface, despite the normal presence of ADAM2 in testicular germ cells. The appearance of ADAM1b and ADAM2 on the sperm surface depended on formation and abundance of ADAM1b/ADAM2 fertilin in testicular germ cells. These results suggest that mouse ADAM1b/ADAM2 fertilin may play a crucial role not in the sperm/egg fusion but in the appearance of these two ADAMs on the sperm surface.
Kim
Ekyune
E
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan.
Yamashita
Misuzu
M
Nakanishi
Tomoko
T
Park
Ki-Eun
KE
Kimura
Masanori
M
Kashiwabara
Shin-ichi
S
Baba
Tadashi
T
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D005260:Female; D000072196:Fertilins; D005306:Fertilization; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D010057:Oviducts / Q000166:cytology / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism
D008562:Membrane Glycoproteins; D051722:ADAM Proteins; C000606454:ADAM2 protein, human; C000606457:Adam1b protein, mouse; C000606458:Adam2 protein, mouse; D000072196:Fertilins