Comparative overview of RNA polymerase II and III transcription cycles, with focus on RNA polymerase III termination and reinitiation

Abstract

In eukaryotes, RNA polymerase (RNAP) III transcribes hundreds of genes for tRNAs and 5S rRNA, among others, which share similar promoters and stable transcription initiation complexes (TIC), which support rapid RNAP III recycling. In contrast, RNAP II transcribes a large number of genes with highly variable promoters and interacting factors, which exert fine regulatory control over TIC lability and modifications of RNAP II at different transitional points in the transcription cycle. We review data that illustrate a relatively smooth continuity of RNAP III initiation-elongation-termination and reinitiation toward its function to produce high levels of tRNAs and other RNAs that support growth and development.

Keywords: :

• BREd
• BREu
• DPE
• Inr
• MTE
• Motif 10 element
• RNA polymerase III
• TAF
• TFIID-associated factors
• TFIIIB
• TFIIIC
• downstream B recognition element
• downstream promoter element
• facilitated recycling
• facilitated reinitiation
• initiator element
• polymerase recycling
• term
• terminator
• transcription reinitiation
• upstream B recognition element

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We thank GA Kassavetis (UCSD) and Mikhail Kashlev (NCI, NIH) for consultation. This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH. RJM is a member of the US Public Health Service Commissioned Corps.