The in vivo role of alpha-mannosidase IIx and its role in processing of N-glycans in spermatogenesis.
The surfaces of mammalian cells are covered by a variety of carbohydrates linked to proteins and lipids. N-glycans are commonly found carbohydrates in plasma membrane proteins. The structure and biosynthetic pathway of N-glycans have been analyzed extensively. However, functional analysis of cell surface N-glycans is just under way with recent studies of targeted disruption of genes involved in N-glycan synthesis. This review briefly introduces the potential role of processing alpha-mannosidases in N-glycan biosynthesis and recent findings derived from the alpha-mannosidase IIx (MX) gene knockout mouse, which shows male infertility. Thus, the MX gene knockout experiment unveiled a novel function of specific N-glycan, which is N-acetylglucosamine-terminated and fucosylated triantennary structure, in the adhesion between germ cells and Sertoli cells. Analysis of the MX gene knockout mouse is a good example of a multidisciplinary approach leading to a novel discovery in the emerging field of glycobiology.
Fukuda
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MN
The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA. michiko@burnham-inst.org
Akama
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TO
D000818:Animals; D007248:Infertility, Male / Q000235:genetics; D008297:Male; D008322:Mammals; D008361:Mannosidases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D011134:Polysaccharides / Q000378:metabolism*; D013091:Spermatogenesis / Q000502:physiology*
D011134:Polysaccharides; D008361:Mannosidases; C499170:Man2a2 protein, mouse