[6] Several studies have been conducted with Saccharomyces cerevisiae to explore the exact function of upstream activation sequences, often focusing on the aforementioned GAL1-GAL10 intergenic region.
[8] One study explored the galactose-responsive upstream activation sequence (UASG), looking at the influence of proximity to this UAS for nucleosome positioning.
This hybrid promoter was then utilized to express human immune interferon, a toxic substance to yeast that results in a reduced copy number and low plasmid stability.
When compared to the native GPD promoter, the presence of UASG caused the transcriptional activity to remain equivalently enhanced under induced conditions.
[11] One study explored the interaction between Ino4p and Ino2p in more depth, examining the dimerization that takes place between the two prior to binding to the promoter of the INO1 gene and activating transcription.
One allele of REG1, the suppressor mutant sia1-1, was capable of suppressing the inositol auxotrophy, revealing a possible pathway for the repression of inositol-sensitive upstream activating sequence-containing genes of yeast.