IDENTIFICATION OF A CRYPROCOCCUS NEOFORMANS GENE THAT DIRECTS EXPRESSION OF THE CRYPTIC SACCHAROMYCES-CEREVISIAE MANNITOL DEHYDROGENASE GENE

The Mtl gene from Cryptococcus neoformans, which confers the ability o f Saccharomyces cerevisiae Sc41 YJO to grow on mannitol with substanti al NAD-dependent mannitol dehydrogenase activity, was identified. Puri fications and characterizations of this enzyme show that it is found i n polyploid strain BB1, and the peptide sequence of the enzyme helped identify the saccharomyces gene encoding this mannitol dehydrogenase a ctivity. On the other hand, the Mtl gene of C. neoformans encodes a 34 6-amino-acid protein which is not mannitol dehydrogenase but a regulat ory element which is active in a heterologous fungus.