Squelching is a biological phenomenon in which a strong

transcriptional activator A transcriptional activator is a protein (transcription factor) that increases transcription of a gene or set of genes. Activators are considered to have ''positive'' control over gene expression, as they function to promote gene transcription and ...

acts to inhibit the expression of another

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. Squelching has been mostly studied in yeast, and most of the ideas regarding its mechanisms have come from research into modes of transcriptional control in yeast. One important study of this topic was conducted using the Gal4-VP16 artificial transcription factor system, where it was shown that the activating complex formed by

VP-16 VP-16, nicknamed the ''War Eagles'', is an active Patrol Squadron of the U.S. Navy. It has been based at NAS Jacksonville, Florida since its founding in 1946. The squadron's mission is to operate Maritime patrol aircraft to the fleet in support ...

was sequestering adapters required for transcription of other targets.Heslot, H., and Claude Gaillardin. Molecular Biology and Genetic Engineering of Yeasts. Boca Raton, Fla.: CRC Press, 1992. Print. The primary cause of squelching is believed to be the interaction of activator molecules disrupting the biochemical pathways associated with related processes due to structural similarity between the activators and important substrates along that pathway. In particular, the activator binds to

transcription factors In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The f ...

along alternative biochemical pathways, inhibiting the ability of these transcription factors to bind to their true targets. As in the example above, sequestration of an intermediate in a metabolic pathway is a confounding variable in genetic studies because knowledge of the expected binding targets of the primary molecules involved does not help predict why unexpected behavior results.

References

{{Reflist Cell signaling Cellular processes Metabolic pathways