Related Experiment Video
Updated: Jun 5, 2025
08:45
Characterizing RNA Modifications in Single Neurons Using Mass Spectrometry
Published on: April 21, 2022
2.3K
Spatial regulation of NSUN2-mediated tRNA m5C installation in cognitive function
Yulia Gonskikh1, Christian Tirrito2,3, Praneeth Bommisetti1
1Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Nucleic Acids Research
|December 14, 2024
Summary
Intellectual disability mutations in NSUN2 impair tRNA 5-methylcytosine (m5C) modification, impacting cognitive function. Reduced tRNA binding, not just localization, explains this impairment, highlighting m5C
Area of Science:
- Molecular Biology
- Neuroscience
- Genetics
Background:
- Enzyme-mediated modifications of transfer RNA (tRNA), specifically 5-methylcytosine (m5C), are crucial for neuronal development and function.
- The nuclear-enriched NOP2/Sun RNA methyltransferase 2 (NSUN2) enzyme installs m5C modifications on tRNA.
- The precise spatial installation and biological roles of these tRNA modifications are not fully understood.
Purpose of the Study:
- To investigate the molecular mechanism by which a specific NSUN2 mutation (G679R), associated with intellectual disability, affects tRNA m5C installation.
- To determine the impact of NSUN2-mediated tRNA m5C modification and its cellular localization on cognitive performance.
- To elucidate the role of NSUN2's intrinsically disordered region (IDR) in tRNA m5C modification and localization.
Main Methods:
- Utilized human cell lines and Drosophila melanogaster models to study NSUN2 function and tRNA m5C levels.
- Generated and analyzed a nucleoplasm-localized G679R NSUN2 mutant and a variant lacking the intrinsically disordered region (ΔIDR-NSUN2).
- Assessed tRNA binding affinity of NSUN2 variants and measured m5C levels in relation to social behavioral deficits in Drosophila.
Main Results:
- The G679R NSUN2 mutant, linked to intellectual disability, significantly reduces tRNA m5C levels in both cell lines and Drosophila.
- The G679R mutant's reduced capacity to install m5C is primarily due to decreased binding to tRNA, not its nucleoplasmic localization.
- A ΔIDR-NSUN2 variant efficiently installs m5C within the nucleoplasm, demonstrating the IDR's role in localization.
- Higher tRNA m5C levels correlate positively with cognitive performance in Drosophila; the G679R mutation causes severe social deficits.
Conclusions:
- The G679R NSUN2 mutation impairs cognitive function by diminishing tRNA m5C modification, mainly through reduced tRNA binding.
- Cellular localization of m5C installation on tRNA is significant for neuronal function, as shown by the differential effects of NSUN2 variants.
- This study provides mechanistic insights into NSUN2-related intellectual disability and the importance of tRNA modifications in cognitive processes.
Related Concept Videos
02:22Regulated mRNA Transport
6.2K
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing...
6.2K
01:23Regulation of Expression at Multiple Steps
869
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the...
869
02:41Chromatin Structure Regulates pre-mRNA Processing
6.9K
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
6.9K
02:24Regulation of Expression Occurs at Multiple Steps
22.4K
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
22.4K
01:45Regulation of Nuclear Protein Sorting
2.4K
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
2.4K
01:53RNA Stability
33.3K
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
33.3K