English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The yeast zinc cluster protein HAP1, a member of the GAL4 family, is a transcriptional activator that binds as a homodimer to target DNA sequences. These targets include the upstream activating sequences of the CYC1 and CYC7 genes, which have no obvious sequence similarity. Even though both sites have the same affinity for HAP1, activation differs at these two sites, even when the sequences are placed in an identical promoter context. In addition, mutants of HAP1 that can bind to both sites but are specifically transcriptionally inactive at CYC7 have been previously isolated. In order to identify nucleotides that are responsible for this differential activity, we have performed random and site-directed mutagenesis of these target sites and assayed their binding to HAP1 in vitro and their activity in vivo in reporter plasmids. Our results show that HAP1 binding sites are degenerate forms of the direct repeat CGG N3 TA N CGG N3 TA. Moreover, we show that activity of HAP1 mutants defective for activation of the CYC7gene is restored by specific mutations in the CYC7 binding site. Conversely, other mutations of the target sites prevent activation by HAP1, without interfering with DNA binding. The results suggest that the sequence of the target sites influences the conformation and, hence, the activity of DNA-bound HAP1.

Mutations in target DNA elements of yeast HAP1 modulate its transcriptional activity without affecting DNA binding