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Updated: Jul 11, 2026

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
A class III transcription factor composed of RNA
L S Young1, H M Dunstan, P R Witte
1Institute of Molecular Biology, University of Oregon, Eugene 97403.
Abstract:
It is generally assumed that the machinery that transcribes genes is composed entirely of polypeptides. However, in vitro transcription by silkworm RNA polymerase III requires a transcription factor that is not a polypeptide. This component, TFIIIR, is distinct from the previously identified transcription components: RNA polymerase III, and the accessory factors TFIIIA, TFIIIB, TFIIIC, and TFIIID. The newly discovered TFIIIR is a macromolecule that appears to be composed of RNA. It is resistant to heat, detergent, phenol, protease, and deoxyribonuclease, but it is sensitive to alkali and ribonuclease.
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