Related Experiment Videos
A reverse transcriptase/maturase promotes splicing by binding at its own coding segment in a group II intron RNA
H Wank1, J SanFilippo, R N Singh
1Department of Chemistry and Biochemistry, University of Texas at Austin 78712, USA.
Molecular Cell
|September 17, 1999
Summary
Group II introns utilize maturase (LtrA) reverse transcriptases for RNA splicing and mobility. LtrA binds intron domain IV near its start codon, facilitating reverse transcription during target DNA-primed reverse transcription.
Area of Science:
- Molecular Biology
- Genetics
- RNA Biology
Background:
- Group II introns are mobile genetic elements encoding reverse transcriptases.
- These enzymes possess maturase activity for RNA splicing and endonuclease activity for mobility via target DNA-primed reverse transcription (TPRT).
Purpose of the Study:
- To identify the primary binding site of the Lactococcus lactis Ll.LtrB intron maturase (LtrA).
- To understand how LtrA binding facilitates its enzymatic activities, particularly reverse transcription.
Main Methods:
- RNA-protein binding assays to map LtrA interaction sites within the Ll.LtrB intron.
- Analysis of secondary structure elements and their contribution to LtrA binding.
Main Results:
- The primary binding site for LtrA was localized to a region within intron domain IV, encompassing the LtrA open reading frame (ORF) start codon.
- LtrA binding is enhanced by interactions with intron domain I and EBS/IBS base-pairing.
- This binding arrangement positions LtrA for initiating cDNA synthesis in the 3' exon during TPRT.
Conclusions:
- LtrA binding to domain IV is crucial for its maturase function in RNA splicing.
- The findings support the hypothesis that the reverse transcriptase-coding region originated from an independent genetic element inserted into group II introns.
- This study elucidates the mechanism of maturase function and intron-mediated DNA integration.