Integrator-Dependent and Allosteric/Intrinsic Mechanisms Ensure Efficient Termination of snRNA Transcription

Autor: Laura Francis, Lee Davidson, Steven West, Joshua D. Eaton
Rok vydání: 2020
Předmět:
Zdroj: Cell Reports
ISSN: 2211-1247
Popis: Summary Many RNA polymerases terminate transcription using allosteric/intrinsic mechanisms, whereby protein alterations or nucleotide sequences promote their release from DNA. RNA polymerase II (Pol II) is somewhat different based on its behavior at protein-coding genes where termination additionally requires endoribonucleolytic cleavage and subsequent 5′→3′ exoribonuclease activity. The Pol-II-transcribed small nuclear RNAs (snRNAs) also undergo endoribonucleolytic cleavage by the Integrator complex, which promotes their transcriptional termination. Here, we confirm the involvement of Integrator but show that Integrator-independent processes can terminate snRNA transcription both in its absence and naturally. This is often associated with exosome degradation of snRNA precursors that long-read sequencing analysis reveals as frequently terminating at T-runs located downstream of some snRNAs. This finding suggests a unifying vulnerability of RNA polymerases to such sequences given their well-known roles in terminating Pol III and bacterial RNA polymerase.
Graphical Abstract
Highlights • Integrator-dependent and -independent mechanisms terminate snRNA transcription • Integrator-independent termination is allosteric/intrinsic in nature • Sites of allosteric/intrinsic termination often coincide with T-runs • Some Pol II termination may share features with Pol III/prokaryotic mechanisms
Davidson et al. show that termination of RNA polymerase II transcription at human snRNA genes can occur by Integrator-dependent and -independent pathways. The latter uses an allosteric/intrinsic mechanism most efficiently detected where T-runs are present in the non-template strand. This is reminiscent of the way many other RNA polymerases terminate.
Databáze: OpenAIRE