Epidermal growth-factor-induced transcript isoform variation drives mammary cell migration.

Area of Science:

• Molecular biology
• Cell biology
• Genomics

Background:

• Signal-induced transcript isoform variation (TIV) encompasses changes in mRNA processing, including alternative promoter usage, splicing, and polyadenylation.
• Understanding the functional consequences of TIV is critical for comprehending cellular responses to external stimuli.

Purpose of the Study:

• To investigate the phenotypic relevance of signal-induced TIV in breast epithelial cells.
• To determine the temporal dynamics and scope of TIV in response to epidermal growth factor (EGF).

Main Methods:

• Utilized exon arrays to analyze TIV in breast epithelial cells stimulated with EGF.
• Employed isoform-specific small interfering RNA (siRNA) for functional screening.
• Analyzed EGF-induced changes across multiple mammary cell lines.

Main Results:

• EGF rapidly induced widespread TIV within one hour in a significant portion of the transcriptome.
• TIV was observed in genes without differential expression, highlighting its distinct role.
• EGF-dependent TIV patterns were conserved across different mammary cell lines.
• Functional screening revealed essential, non-redundant roles for specific isoforms in EGF-induced cell migration.

Conclusions:

• Signal-induced TIV plays a significant role in the rapid phenotypic adaptation of cells to extracellular signals.
• TIV contributes to cellular functions like migration independently of changes in overall gene expression levels.
• The findings underscore the importance of considering transcript isoforms when studying cellular responses and phenotypes.