What is the likely effect of each of the following mutations of the trpL region on attenuation control of trp operon gene transcription? Explain your reasoning.

The entire trpL region is deleted.

Key Concepts

Attenuation Control

Attenuation control is a regulatory mechanism in prokaryotes, particularly in the trp operon, that modulates gene expression based on the availability of tryptophan. It involves the formation of specific RNA structures during transcription that can either promote or inhibit the continuation of transcription depending on the cellular conditions. This process allows bacteria to efficiently respond to nutrient availability.

trp Operon

The trp operon is a cluster of genes in bacteria that encode enzymes necessary for the biosynthesis of the amino acid tryptophan. It is regulated by both repression and attenuation mechanisms, allowing the cell to conserve resources when tryptophan is abundant. The operon consists of structural genes, a promoter, and regulatory sequences that respond to tryptophan levels.

trpL Region

The trpL region, or leader sequence, is a short segment of RNA located upstream of the structural genes in the trp operon. It contains sequences that can form alternative secondary structures, influencing the transcription process. Deletion of the trpL region disrupts these structures, which can lead to the loss of attenuation control, resulting in continuous transcription of the operon regardless of tryptophan levels.