Lack of a requirement for strict rotational alignment among transcription factor binding sites in yeast
1991
Inokuchi, K. | Nakayama, A.
The MFalpha-1 gene of Saccharomyces cerevisiae is an alpha specific gene whose expression is regulated by two upstream activation sites (UASmfalpha-1s), which are the binding sites for activator proteins, MATalpha-1 and MCM1. UASmfalpha-1 elements act in a synergistic fashion; lack of either element causes reduced expression levels that are 6- to 45-fold less than that of intact promoter in a cells. We investigated the effect of manipulating rotational alignments among transcription factor binding sites of MFalpha-1 on the expression of the gene. The expression level of MFalpha-1 decreased with the spacing between the two UASmfalpha-1s and no synergism was observed when the distance of the two elements was longer than 90 base pairs. No strict rotational alignment was required for their synergistic action. We also show that the spacing between UASmfalpha-1 elements and TFIID binding site, the TATA box, had little, if any, effect on MFalpha1 expression. We chose a sufficient number of positions for UASmfalpha-1s to ensure that, in several of these positions, MATalpha-1 and MCM1 were on the opposite side of the DNA helix with respect to the TATA box.
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