The Drosophila GMII gene encodes a Golgi alpha-mannosidase II

In this paper we show the organisation of the Drosophila gene encoding a Golgi alpha-mannosidase II. We demonstrate that it encodes a functional homologue of the mouse Golgi alpha-mannosidase II. The Drosophila and mouse cDNA sequences translate into amino acid sequences which show 41% identity and 61% similarity. Expression of the Drosophila GMII sequence in CHOP cells produces an enzyme which has mannosidase activity and is inhibited by swainsonine and by CuSO(4.) In cultured Drosophila cells and in Drosophila embryos, antibodies raised against a C-terminal peptide localise this product mainly to the Golgi apparatus as identified by cryo-immuno electron microscopy studies and by antibodies raised against known mammalian Golgi proteins. We discuss these results in terms of the possible use of dGMII as a Drosophila Golgi marker.