EXPRESSION OF AN ALPHA-GALACTOSIDASE GENE UNDER CONTROL OF THE HOMOLOGOUS INULINASE PROMOTER IN KLUYVEROMYCES-MARXIANUS

For expression of the alpha-galactosidase gene from Cyamopsis tetragon oloba in Kluyveromyces marxianus CBS 6556 we have used the promoter of the homologous inulinase-encoding gene (INU1). The INU1 gene has been cloned and sequenced and the coding region shows an identity of 59% w ith the Saccharomyces cerevisiae invertase gene (SUC2). In the 5'-flan king region of INU1 we found a sequence (TAAATCCGGGG) that perfectly m atches to the MIG1 binding consensus sequence (WWWWTSYGGGG) of the S. cerevisiae GAL1, GAL4 and SUC2 genes. Using the K. marxianus INU1 prom oter and prepro-signal sequence, we obtained a high alpha-galactosidas e production level (153 mg/l) and a secretion efficiency of 99%. Both the production level and the secretion efficiency were significantly r educed when the INU1 pro-peptide was deleted. With either the S. cerev isiae PGK or GAL7 promoter we could obtain only low a-galactosidase pr oduction levels (2 mg/l).