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Transcriptional activators differ in their abilities to control alternative splicing
Guadalupe Nogues1, Sebastian Kadener, Paula Cramer
1Laboratorio de Fisiologia y Biologia Molecular, Departamento de Fisiologia, Biologia Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, C1428EHA Buenos Aires, Argentina.
The Journal of Biological Chemistry
|September 11, 2002
Summary
Transcriptional activators influence alternative splicing by affecting RNA polymerase II (pol II) elongation rates. Faster pol II elongation promotes exon skipping, while slower elongation favors exon inclusion, supporting a kinetic coupling model.
Area of Science:
- Molecular Biology
- Gene Regulation
- RNA Splicing
Background:
- Promoters and enhancers can impact alternative splicing, but the underlying mechanisms remain unclear.
- Alternative splicing, specifically exon skipping, is a crucial process in gene expression regulation.
Purpose of the Study:
- To investigate how transcriptional activators influence the inclusion or exclusion of the fibronectin EDI exon.
- To elucidate the relationship between transcriptional elongation efficiency and alternative splicing outcomes.
Main Methods:
- Utilized a mutant VP16 activation domain (SW6) to modulate RNA polymerase II (pol II) elongation.
- Assessed the effects of cis-acting enhancers (SV40) and trans-acting factors (HIV Tat) on EDI exon splicing.
- Employed elongation inhibitors (DRB) and stimulators (trichostatin A) to study their impact on splicing.
Main Results:
- Inhibition of pol II elongation reduced EDI exon skipping.
- Stimulation of pol II elongation by SV40 enhancer or HIV Tat restored and enhanced EDI exon skipping.
- Exon skipping efficiency correlated with transcript elongation to the gene's 3' end, not overall transcript levels.
Conclusions:
- Transcriptional elongation rate is a key determinant of alternative splicing decisions, specifically for the EDI exon.
- A kinetic coupling model is proposed, where rapid, processive transcription favors exon skipping, and slower transcription favors inclusion.
- These findings highlight the interplay between transcription and splicing in co-transcriptional gene expression.