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Published on: August 26, 2012
RNA polymerase I contains a TFIIF-related DNA-binding subcomplex
Sebastian R Geiger1, Kristina Lorenzen, Amelie Schreieck
1Gene Center and Department of Biochemistry, Center for Integrated Protein Science CIPSM, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Molecular Cell
|August 28, 2010
Summary
Specific subunits of RNA Polymerase I (Pol I) and III (Pol III) are evolutionarily linked to RNA Polymerase II (Pol II) initiation factors. These subunits may control promoter specificity and transcription processivity.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Eukaryotic RNA polymerases (Pol I, II, and III) transcribe distinct gene classes using specific promoters.
- RNA Polymerase II (Pol II) promoter utilization depends on initiation factors like TFIIF and TFIIE.
Purpose of the Study:
- To investigate the evolutionary and functional relationship between Pol I/III-specific subunits and Pol II initiation factors.
- To elucidate the role of Pol I-specific subunits A49 and A34.5 in DNA binding and transcription.
Main Methods:
- Structural analysis of Pol I subunits A49 and A34.5.
- Biochemical assays to determine DNA-binding properties and polymerase activity.
- Bioinformatic predictions of domain structures and evolutionary relationships.
Main Results:
- The Pol I-specific A49/A34.5 subcomplex binds DNA and shows structural similarities to TFIIF and TFIIE.
- The N-terminal regions of A49/A34.5 form a dimerization module that enhances RNA cleavage.
- The C-terminal region of A49 contains a tandem winged helix (tWH) domain that binds DNA, similar to TFIIE.
Conclusions:
- Pol I/III subunits lacking Pol II counterparts are evolutionarily related to Pol II initiation factors.
- These subunits likely evolved to confer promoter specificity and enhance transcription processivity for Pol I and Pol III.
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