Molecular and genetic analysis of the Drosophila mas-1 (mannosidase-1) gene which encodes a glycoprotein processing alpha 1,2-mannosidase

Dev Biol. 1995 Apr;168(2):613-26. doi: 10.1006/dbio.1995.1106.


Glycosylation is an important mechanism for modulating the physicochemical and biological properties of proteins in a stage- and tissue-specific manner. The enzymology of this process is just beginning to be understood. Here we present the molecular analysis of mas-1 (mannosidase-1), a Drosophila gene with significant homologies to mammalian and Saccharomyces cerevisiae glycoprotein processing alpha 1,2-mannosidases. An enhancer-trap P-element inserted upstream of mas-1 leads to highly specific lacZ expression in the lobula plate giant neurons, cells that mediate the large-field optomotor response. This staining, however, seems to reflect only a small part of the complex expression pattern of the mas-1 gene: Two promoters produce alternative transcripts that show individual spatial distributions during embryonic development, including a maternal contribution. Both transcripts code for type II transmembrane proteins which differ in their N-terminal parts. Null mutants in mas-1 display defects in the embryonic PNS, in the wing, and in the adult eye. These findings illustrate that the processing of N-linked glycans plays a functional role in Drosophila development. There is, however, ample evidence for genetic and biochemical redundancy in the mannose-trimming steps of this pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Drosophila / genetics*
  • Drosophila / metabolism
  • Mannosidases / biosynthesis
  • Mannosidases / genetics*
  • Molecular Sequence Data
  • Sequence Alignment


  • Mannosidases
  • mannosyl-oligosaccharide 1,2-alpha-mannosidase

Associated data

  • GENBANK/X82640
  • GENBANK/X82641