Molecular Genetics and Genomics

, Volume 286, Issue 5–6, pp 395–410

RNA splicing and debranching viewed through analysis of RNA lariats

Original Paper


Intron lariat RNAs, created by pre-mRNA splicing, are sources of information on gene expression and structure. Although produced equivalently to their corresponding mRNAs, the vast majority of intron lariat RNAs are rapidly degraded. However, their levels are enhanced in cells deficient for RNA debranching enzyme, which catalyzes linearization of these RNAs, the rate-limiting step in their degradation. Furthermore, RNA lariats are resistant to degradation by the 3′ exonuclease polynucleotide phosphorylase (PNPase), providing a means to enrich for lariat RNAs. Working with the yeast Saccharomyces cerevisiae as a model organism, our goal was to develop novel combinations of methods to enhance the use of intron lariat RNAs as objects of study. Using RT-PCR assays developed for detecting and quantifying specific lariat RNAs, we demonstrate the resistance of RNA lariats to degradation by PNPase and their sensitivity to cleavage by RNA debranching enzyme. We also employ sequential treatments with these two enzymes to produce characteristic effects on linear and lariat RNAs. We establish the utility of the methods for analyzing RNA debranching enzyme variants and in vitro debranching reactions and discuss several possible applications, including measuring relative rates of transcription and combining these methods with non-gene-specific RNA sequencing as a novel approach for genome annotation. In summary, enzymatic treatments that produce characteristic effects on linear and lariat RNAs, combined with RT-PCR or RNA sequencing, can be powerful tools to advance studies on gene expression, alternative splicing, and any process that depends on the RNA debranching enzyme.


Intron RNA lariats Debranching enzyme Dbr1 Polynucleotide phosphorylase mRNA splicing Yeast Ty1 retrotransposon 

Supplementary material

438_2011_635_MOESM1_ESM.pdf (20 kb)
Supplementary Figure S1 (pdf 19.5 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.School of Biological SciencesUniversity of Missouri-Kansas CityKansas CityUSA
  2. 2.The Pediatric Surgery Laboratory, Department of SurgeryCedars-Sinai Medical CenterLos AngelesUSA

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