The phylogenetically widespread group I and group II introns are dynamic gentic elements. They splice by different self-catalyzed RNA- based mechanisms, while many are also capable of insertion into DNA through distinct mobility pathways. For each calss of intron, mobility characteristically takes the form of 'homing', whereby the intron transfers to an intronless DNA allele via a double-strand break created by an intron-encoded endonuclease. Whereas for group I homing, recombination events are strictly DNA-based, group II homing involves RNA at levels of both the template and the cleavage enzyme for mobility. The overall goal of this work is to use prokaryotic genetic systems to study both DNA-based and RNA-based intron rearrangements. During the past funding period we made progress towards defining structural and functional requirements of group I intron homing in the T4 phage system and determined that the process occurs by multiple recombination pathways. Furthermore, we advanced our understanding of protein-assisted RNA-based reactions by identifying E. Coli proteins that exhibit RNA chaperone activity in vitro. We also obtained evidence that supports an gypothesis for how mobile group I introns evolved, by invasion of an endonuclease gene into DNA encoding the self-splicing intron. For the next funding period we propose to extend the studies defining the group I mobility process. We will also continue our work on protein-assisted splicing, by probing the mechanism of StpA, an E. Coli protein with RNA chaperone activity, and by analyzing the Neurospora splicing effector CYT-18 in E. coli. Additionally, we wish to extend our work to studying bacterial group II intron homing, a process dependent upon both RNA splicing and DNA recombination. Thus, by exploiting eubacterial genetic systems and combining the approaches of genetic analysis, biochemical characterization and structural study, we propose to advance our understanding of intron- related nucleic acid dynamics.
| Pearson, C Seth; Nemati, Reza; Liu, Binbin et al. (2018) Structure of an Engineered Intein Reveals Thiazoline Ring and Provides Mechanistic Insight. Biotechnol Bioeng : |
| Qu, Guosheng; Piazza, Carol Lyn; Smith, Dorie et al. (2018) Group II intron inhibits conjugative relaxase expression in bacteria by mRNA targeting. Elife 7: |
| Lennon, Christopher W; Stanger, Matthew; Banavali, Nilesh K et al. (2018) Conditional Protein Splicing Switch in Hyperthermophiles through an Intein-Extein Partnership. MBio 9: |
| Kelley, Danielle S; Lennon, Christopher W; Li, Zhong et al. (2018) Mycobacterial DnaB helicase intein as oxidative stress sensor. Nat Commun 9:4363 |
| Green, Cathleen M; Novikova, Olga; Belfort, Marlene (2018) The dynamic intein landscape of eukaryotes. Mob DNA 9:4 |
| Dong, Xiaolong; Ranganathan, Srivathsan; Qu, Guosheng et al. (2018) Structural accommodations accompanying splicing of a group II intron RNP. Nucleic Acids Res 46:8542-8556 |
| Belfort, Marlene (2017) Mobile self-splicing introns and inteins as environmental sensors. Curr Opin Microbiol 38:51-58 |
| Lennon, Christopher W; Belfort, Marlene (2017) Inteins. Curr Biol 27:R204-R206 |
| Novikova, Olga; Belfort, Marlene (2017) Mobile Group II Introns as Ancestral Eukaryotic Elements. Trends Genet 33:773-783 |
| Agrawal, Rajendra Kumar; Wang, Hong-Wei; Belfort, Marlene (2016) Forks in the tracks: Group II introns, spliceosomes, telomeres and beyond. RNA Biol 13:1218-1222 |
Showing the most recent 10 out of 124 publications
