The Drosophila GMII gene encodes a Golgi alpha-mannosidase II

In this paper we show the organisation of the Drosophila gene encoding a Go lgi alpha-mannosidase II. We demonstrate that it encodes a functional homol ogue of the mouse Golgi a-mannosidase II. The Drosophila and mouse cDNA seq uences translate into amino acid sequences which show 41% identity and 61% similarity. Expression of the Drosophila GMII sequence in CHOP cells produc es an enzyme which has mannosidase activity and is inhibited by swainsonine and by CuSO4. In cultured Drosophila cells and in Drosophila embryos, anti bodies raised against a C-terminal peptide localise this product mainly to the Golgi apparatus as identified by cryo-immuno electron microscopy studie s and by antibodies raised against known mammalian Golgi proteins. We discu ss these results in terms of the possible use of dGMII as a Drosophila Golg i marker.