Lysosomal alpha-mannosidases of mouse tissues: characteristics of the isoenzymes, and cloning and expression of a full-length cDNA.
Lysosomal alpha-d-mannosidase from mouse tissues was separated into its constituent isoenzymes by DEAE-cellulose chromatography. Forms corresponding to the human isoenzymes B and A were present in testis, brain, spleen and kidney, whereas in epididymis and liver only the B form was present. Murine alpha-mannosidases A and B are glycoproteins and have pH optima, thermal stabilities and molecular masses similar to those of the human isoenzymes. A full-length cDNA (3.1 kb) containing the complete coding sequence for alpha-mannosidase was isolated from a mouse macrophage cDNA library. Comparison of the deduced amino acid sequences of human and mouse alpha-mannosidases showed that they had 75% identity and 83% similarity. Expression of this cDNA in COS cells showed that both the A and the B isoenzymes can arise from a single transcript. Northern blotting analysis showed a 10-fold range in the abundance of alpha-mannosidase mRNA in mouse tissues, with the highest levels found in epididymis, and the lowest in liver.
Beccari
T
T
Dipartimento di Biologia Cellulare e Molecolare, Università degli Studi di Perugia, Via del Giochetto, 06126 Perugia, Italy.
Appolloni
M G
MG
Costanzi
E
E
Stinchi
S
S
Stirling
J L
JL
Della Fazia
M A
MA
Servillo
G
G
Viola
M P
MP
Orlacchio
A
A
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D019556:COS Cells; D002848:Chromatography, DEAE-Cellulose; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008247:Lysosomes / Q000201:enzymology*; D008361:Mannosidases / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D043323:alpha-Mannosidase
D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D008361:Mannosidases; D043323:alpha-Mannosidase