MULTIPLE POSITIVE AND NEGATIVE CIS-ACTING ELEMENTS MEDIATE INDUCED ARGINASE (CAR1) GENE-EXPRESSION IN SACCHAROMYCES-CEREVISIAE

Expression of the arginase (CAR1) gene in Saccharomyces cerevisiae is induced by arginine or its analog homoarginine. Induction has been previously shown to require a negatively acting upstream repression sequence, which maintains expression of the gene at a low level in the absence of inducer. The objective of this work was to identify the cis-acting elements responsible for CAR1 transcriptional activation and response to inducer. We identified three upstream activation sequences (UASs) that suppport transcriptional activation in a heterologous expression vector. Two of these UAS elements function in the absence of inducer, whereas the third functions only when inducer is present. One of the inducer-dependent UAS elements exhibits significant homology to the Sp1 factor-binding sites identified in simian virus 40 and various mammalian genes.