What is the primary function of GAL4 in gene regulation?

The primary function of GAL4 in gene regulation is to regulate genes needed to utilize galactose. GAL4 is a transcription factor found in yeast that plays a crucial role in the galactose metabolic pathway. When galactose is present, GAL4 binds to specific upstream activating sequences (UAS) in the promoters of target genes, facilitating the transcription of genes that encode enzymes necessary for the metabolism of galactose.

This regulatory mechanism allows yeast cells to adapt to the availability of galactose in their environment, activating the expression of genes required for its utilization while remaining silent in the absence of the sugar. Thus, the role of GAL4 is essential for coordinating the expression of metabolic genes in response to environmental signals, specifically the presence of galactose.