Given the task definition and input, reply with output. In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

When targeted to the GAL1 promoter by fusing with the Gal4p DNA - binding domain , Sko1p acts as an Ssn6 / Tup1p - dependent repressor regulated by osmotic stress .
GAL1 promoter