Disease relevance of Man2a2

• 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 [1].
• Some MX proteins are known to confer a specific resistance against a panel of single-stranded RNA viruses [2].

High impact information on Man2a2

• The Man2a2 null spermatogenic cells fail to adhere to Sertoli cells and are prematurely released from the testis to epididymis [3].
• Recombinant mouse MX and MII showed identical substrate specificities toward N-glycan substrates, suggesting that MX is an isozyme of MII [4].
• The in vivo role of alpha-mannosidase IIx and its role in processing of N-glycans in spermatogenesis [1].
• 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 [1].
• Quantitative profiling of all N-glycan structures including minor components from MII/MX nulls, MII nulls, MX nulls, and wild-type mice at embryonic day 15.5 yielded a total of 37 species when structural heterogeneity was reduced by the removal of the sialic acids [5].

Biological context of Man2a2

• In vivo role of alpha-mannosidase IIx: ineffective spermatogenesis resulting from targeted disruption of the Man2a2 in the mouse [6].
• Histology of the MX null mouse testis showed significant reduction of spermatogenic cells in the seminiferous tubules [6].
• The targeted disruption of the gene encoding MX in the mouse resulted in an obvious phenotype, i.e., MX-deficient males were found to be infertile [6].

Anatomical context of Man2a2

• The MX gene knockout experiments unveiled a novel function of a specific N-glycan, which is N-acetylglucosamine-terminated and has a fucosylated triantennary structure, in the adhesion between germ cells and Sertoli cells [7].
• Electron microscopy showed that prominent intercellular spaces surround MX-deficient spermatogenic cells, suggesting a failure of germ cell adhesion to Sertoli cells [6].

Associations of Man2a2 with chemical compounds

• Quantitative structural analyses of N-glycans from wild-type and MX-deficient mouse testis showed that wild-type testes contain GlcNAc-terminated complex type N-glycans, while they are significantly reduced in MX-deficient mutant testis [6].

Other interactions of Man2a2

• Alpha-mannosidase IIx (MX) was identified as the gene product of processing alpha-mannosidase II (MII)-related gene [7].

References