Group II intron inhibits conjugative relaxase expression in bacteria by mRNA targeting

Authors

Marlene Belfort, University at Albany, State University of New York
Dorie Smith, University at Albany, State University of New York
Carol Lyn Pizza, University at Albany, State University of New York
Guosheng Qu, University at Albany, State University of New York

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Document Type

Article

Publication Date

2018

DOI

https://doi.org/10.7554/eLife.34268.001

Abstract

Group II introns are mobile ribozymes that are rare in bacterial genomes, often cohabiting with various mobile elements, and seldom interrupting housekeeping genes. What accounts for this distribution has not been well understood. Here, we demonstrate that Ll.LtrB, the group II intron residing in a relaxase gene on a conjugative plasmid from Lactococcus lactis, inhibits its host gene expression and restrains the naturally cohabiting mobile element from conjugative horizontal transfer. We show that reduction in gene expression is mainly at the mRNA level, and results from the interaction between exon-binding sequences (EBSs) in the intron and intron-binding sequences (IBSs) in the mRNA. The spliced intron targets the relaxase mRNA and reopens ligated exons, causing major mRNA loss. Taken together, this study provides an explanation for the distribution and paucity of group II introns in bacteria, and suggests a potential force for those introns to evolve into spliceosomal introns.

Comments

This is the Publisher’s PDF of the following article made available by eLife: https://doi.org/10.7554/eLife.34268.001

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Belfort, Marlene; Smith, Dorie; Pizza, Carol Lyn; and Qu, Guosheng, "Group II intron inhibits conjugative relaxase expression in bacteria by mRNA targeting" (2018). Biological Sciences Faculty Scholarship. 18.
https://scholarsarchive.library.albany.edu/biology_fac_scholar/18