CLONING AND SEQUENCE-ANALYSIS OF THE INVERTASE GENE INV1 FROM THE YEAST PICHIA-ANOMALA

A genomic library from the yeast Pichia anomala has been constructed a nd employed to clone the gene encoding the sucrose-hydrolysing enzyme invertase by complementation of a sucrose non-fermenting mutant of Sac charomyces cerevisiae. The cloned gene, INV1, was sequenced and found to encode a polypeptide of 550 amino acids which contained a 22 amino- acid signal sequence and ten potential glycosylation sites, The amino- acid sequence shows significant identity with other yeast invertases a nd also with Kluyveromyces marxianus inulinase, a yeast beta-fructofur anosidase which has a different substrate specificity. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain se veral consensus motifs probably involved in the initiation and termina tion of gene transcription.