Enhancers regulate 3' end processing activity to control expression of alternative 3'UTR isoforms.

Area of Science:

• Molecular Biology
• Gene Regulation
• Transcriptomics

Background:

• Alternative 3' untranslated region (UTR) isoforms are expressed in a cell type-specific manner.
• Transcriptional enhancers are known regulators of mRNA expression levels.

Purpose of the Study:

• To investigate whether transcriptional enhancers regulate 3'UTR isoform expression.
• To elucidate the mechanism by which enhancers influence 3'UTR isoform selection.

Main Methods:

• Endogenous enhancer deletion in the PTEN gene.
• Silencing of enhancer-bound transcription factors.
• Reporter assays with single- and multi-UTR gene promoters.
• Analysis of polyadenylation site processing activity.

Main Results:

• Enhancer deletion in PTEN prevented 3'UTR isoform switching without affecting overall transcript production.
• Silencing an enhancer-bound transcription factor recapitulated the effect of enhancer deletion.
• Enhancers increased 3' end processing activity at polyadenylation sites when paired with multi-UTR gene promoters.

Conclusions:

• Transcriptional enhancers play a crucial role in regulating cell type- and condition-specific 3'UTR isoform expression.
• Enhancers integrate cellular signals to modulate alternative polyadenylation and 3'UTR selection.
• This mechanism allows for fine-tuning of gene expression beyond transcript levels.