How does the Gal4 UAS system work?
The Gal4/UAS system Gal4 is a transcriptional activator that binds to UAS enhancer sequences found in DNA. It then recruits transcription machinery to the site to induce gene expression. You can quickly mate your UAS-YFG line with a variety of Gal4 lines and study gene expression in many different tissue types!
What is a UAS promoter?
An upstream activating sequence or upstream activation sequence (UAS) is a cis-acting regulatory sequence. The upstream activation sequence is found adjacently upstream to a minimal promoter (TATA box) and serves as a binding site for transactivators.
What is the function of Gal4?
The broad use of the Gal4 is in yeast two-hybrid screening to screen or to assay protein-protein interactions in eukaryotic cells from yeast to human. In the GAL4/UAS system, the Gal4 protein and Gal4 upstream activating region (UAS) are used to study the gene expression and function in organisms such as the fruit fly.
What is GMR Gal4?
The GMR-GAL4 driver, which expresses the yeast transcription factor GAL4 under the control of glass multiple reporter (GMR) promoter elements, has been commonly utilized to express target transgenes, specifically in the developing eye.
Is GAL4 an activator?
Yeast Gal4, one of the first known acidic activators, is responsible for the regulation of genes involved in galactose catabolism (41). In the absence of galactose, Gal4 is inhibited by the repressor Gal80.
Is UAS a transgene?
The standard expression system used in Drosophila is the bipartite GAL4–UAS system first described by Brand and Perrimon (1993). The transgene of interest is placed downstream of a GAL4 upstream activating sequence that supports transcription of the construct only in the presence of GAL4.
Does GAL4 bind to DNA?
Thus, in the absence of galactose, the GAL4 transcription factor is bound to DNA but its activity is inhibited by the inhibitory GAL80 protein, so that GAL4 only activates transcription when galactose is present (for review see Sellick and Reece, 2005).
What is the effect of Gal80 on GAL4?
The Saccharomyces cerevisiae Gal80 protein has two binding partners: Gal4 and Gal3. In the absence of galactose, Gal80 binds to and inhibits the transcriptional activation domain (AD) of the GAL gene activator, Gal4, preventing GAL gene expression.
How does Gal80 inhibit GAL4?
In the absence of galactose, the Gal80 protein binds to a small peptide (amino acids [aa] 855 to 870) within the Gal4AD and thereby prevents Gal4-mediated promoter activation (10, 11). Galactose converts Gal3 to a form that readily binds to Gal80 (21).
Why do motifs occur in DNA?
Sequence motifs are short, recurring patterns in DNA that are presumed to have a biological function. Often they indicate sequence-specific binding sites for proteins such as nucleases and transcription factors (TF).