Refinement of the expression pattern of a mouse homologue of the porcine 135-kDa alpha-D-mannosidase (MAN2B2)

In the article by Hiramoto et al. (1997) (Stage-specific expression of a mo use homologue of the porcine 135 kDa alpha-D-mannosidase (MAN2B2) in type A spermatogonia, Biochem. Biophys. Res. Commun. 241, 439-445) a new homologu e to the porcine epididymis-specific 135 kDa alpha-D-mannosidase (MAN2B2) w as cloned from a mouse testis cDNA library. Northern blot analysis with RNA of different tissues showed a testis-specific expression by using a mouse MAN2B2 oligonucleotide. In situ hybridization revealed that the mouse MAN2B 2 transcript is localized exclusively in spermatogonia. In consequence to t his it was proposed by Hiramoto et al. that the mouse MAN2B2 homologue coul d serve as a marker for spermatogonia. By repeating the published experimen ts we observed a different expression pattern of the mouse MAN2B2 gene. Nor thern blot analysis with either testicular RNA from prepubertal males or wi th testicular RNA from the W/W-v-mutant mouse which lacks germ cells showed an expression of the MAN2B2 gene. Furthermore, Northern blot analysis with RNA from different somatic tissues revealed that; the gene is ubiquitously expressed. Therefore, our refinement clearly demonstrates that the MAN2B2 mouse homologue is not specifically expressed in spermatogonia. (C) 2000 Ac ademic Press.