The expression of β−galactosidase from each of these promoter deletion constructs under minus-galactose, plus-galactose, and plus galactose & glucose, are show. From these data we can deduce the location of cis-acting regulatory sequences for the Gal1 gene. • Deletions 7 and 8 do not express the reporter under any conditions because the deletions have removed some of the TATA sequence that is required for assembly of the basal transcription machinery. • Deletions 1 and 2 eliminate the ability of galactose to increase expression from the Gal1 promoter, and since expression is not induced there is nothing for glucose to repress. It turns out that the 75bp sequence between -310 and -385 is the DNA binding site for Gal4 and this kind of region is generally called a UAS (upstream activation sequence) and in this case UAS GAL . We will come back to thinking about Gal4 binding to the UAS recognition sequence later. • Deletions 3, 5 and 6 have no effect on the ability of galactose to induce expression because the
This is the end of the preview.
access the rest of the document.