Related Experiment Video
Updated: Jun 25, 2026
09:19
RNA Catalyst as a Reporter for Screening Drugs against RNA Editing in Trypanosomes
Published on: July 22, 2014
Kinetoplastid RNA editing involves a 3' nucleotidyl phosphatase activity
Moritz Niemann1, Heike Kaibel, Elke Schlüter
1Genetics, Darmstadt University of Technology, Darmstadt, Germany.
Nucleic Acids Research
|February 5, 2009
Summary
African trypanosome mitochondrial RNA editing requires a 3' nucleotidyl phosphatase activity. This activity, involving TbMP99 and TbMP100 proteins, is essential for RNA maturation and prevents premature ligation.
Area of Science:
- Molecular Biology
- Parasitology
- Biochemistry
Background:
- Mitochondrial pre-messenger RNAs (pre-mRNAs) in African trypanosomes need RNA editing for functional maturation.
- RNA editing is mediated by the editosome, a large complex with multiple enzymatic activities.
Purpose of the Study:
- To investigate the enzymatic activities of the editosome involved in RNA editing.
- To identify novel reaction steps and protein components contributing to RNA editing in African trypanosomes.
Main Methods:
- Analysis of enzymatic activities associated with the editosome complex.
- Gene ablation and knockdown studies of specific editosomal proteins (TbMP99, TbMP100).
- Assessment of 3' nucleotidyl phosphatase activity and overall RNA editing efficiency.
Main Results:
- RNA editing involves a previously unrecognized 3' nucleotidyl phosphatase activity.
- The editosomal proteins TbMP99 and TbMP100 contribute to this phosphatase activity.
- Simultaneous knockdown of TbMP99 and TbMP100 reduces both phosphatase activity and RNA editing efficiency.
- The exoUase activity of TbMP42 generates 3' phosphate termini, potentially preventing premature ligation.
Conclusions:
- A 3' nucleotidyl phosphatase activity is a crucial component of the RNA editing machinery in African trypanosomes.
- TbMP99 and TbMP100 are key players in this phosphatase activity, with functional redundancy.
- The findings provide a mechanistic explanation for the role of 3' phosphate termini in regulating RNA editing ligation.
Related Concept Videos
02:23RNA Editing
RNA editing is a post-transcriptional modification where a precursor mRNA (pre-mRNA) nucleotide sequence is changed by base insertion, deletion, or modification. The extent of RNA editing varies from a few hundred bases, in mitochondrial DNA of trypanosomes, to a just single base, in nuclear genes of mammals. Even a single base change in the pre-mRNA can convert a codon for one amino acid into the codon for another amino acid or a stop codon. This type of re-coding can significantly affect the...
01:43Proofreading
Synthesis of new DNA molecules starts when DNA polymerase links nucleotides together in a sequence that is complementary to the template DNA strand. DNA polymerase has a higher affinity for the correct base to ensure fidelity in DNA replication. The DNA polymerase furthermore proofreads during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.Errors during Replication Are Corrected by the DNA Polymerase EnzymeGenomic DNA is synthesized in...
01:31Proofreading
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Errors During Replication are Corrected by the DNA Polymerase Enzyme
00:58Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
00:58Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
01:35Pre-mRNA Processing: Modification of pre-mRNA Ends
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...