GO:0000470 maturation of LSU-rRNA: Ribosome Assembly Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000470 maturation of LSU-rRNA describes any process that converts a precursor large subunit ribosomal RNA (LSU-rRNA) into its mature form.
• LSU-rRNA maturation is essential for assembling the large ribosomal subunit and for translation, and defects in this process impair ribosome biogenesis.
• The pathway involves endonucleolytic and exonucleolytic cleavages of precursor rRNA, often guided by conserved processing factors and exosome-associated nucleases.
• LSU-rRNA maturation is conserved but mechanistically diverse across eukaryotes, with lineage-specific complexes and processing sites reported in trypanosomes, fungi, plants, and microsporidia.
• Experimental approaches such as regulated genetic complementation, RNA processing assays, and northern blotting are used to dissect LSU-rRNA maturation factors.
• Dysregulation of LSU-rRNA maturation is linked to ribosome biogenesis stress and has been studied in pathogens and model organisms, making it a target for functional genomics.
Description
GO:0000470 maturation of LSU-rRNA is a biological process defined as any process involved in the maturation of a precursor Large SubUnit (LSU) ribosomal RNA (rRNA) molecule into a mature LSU-rRNA molecule. In eukaryotes, the large ribosomal subunit contains the LSU-rRNA, which is transcribed as part of a long precursor rRNA and must undergo a series of processing events to become functional. This maturation is a prerequisite for ribosome assembly and protein synthesis, and its disruption affects cell growth and viability. Research on LSU-rRNA maturation has revealed that the pathway is not identical across organisms. In the protozoan Trypanosoma brucei, LSU-rRNA is segmented and requires a trypanosome-specific complex for late-stage processing, and the exonuclease RRP44 plays a key role in the maturation of segmented ribosomal RNA. In plants, the nucleolar protein NOL12 is required for processing of large ribosomal subunit rRNA precursors in Arabidopsis. In fungi, alternative post-transcriptional maturation of 26S rRNA has been identified, and in microsporidia, rRNA maturation sites argue against full excision of the presumed ITS1 sequence. These studies highlight the diversity of LSU-rRNA maturation mechanisms and the importance of identifying the factors involved. For researchers, GO:0000470 provides a framework to annotate genes and pathways involved in LSU-rRNA processing. Understanding this process is relevant to ribosome biogenesis, cell growth control, and the biology of pathogens and model organisms. Functional studies using genetic complementation, RNA processing assays, and CRISPR-based models can help determine which factors are causally required for LSU-rRNA maturation.
maturation of LSU-rRNA At A Glance
| GO ID | GO:0000470 |
|---|---|
| GO term | maturation of LSU-rRNA |
| Ontology | biological_process |
| Synonym | None listed |
| Major function | Processing of precursor LSU-rRNA into mature LSU-rRNA for large ribosomal subunit assembly |
| Related process | Ribosome biogenesis and rRNA processing |
| Key factors | RRP44, NOL12, and trypanosome-specific processing complexes |
| Organismal diversity | Documented in trypanosomes, fungi, plants, microsporidia, and other eukaryotes |
| Research methods | Regulated genetic complementation, RNA processing assays, northern blotting, and CRISPR-based models |
What Is GO:0000470?
GO:0000470 maturation of LSU-rRNA is the biological process that encompasses any step required to convert a precursor LSU-rRNA molecule into a mature LSU-rRNA molecule. This includes the cleavage events and processing factors that remove transcribed spacer sequences and generate the mature 3' and 5' ends of the LSU-rRNA. The process is part of ribosome biogenesis and is essential for the formation of functional large ribosomal subunits.
Why Is maturation of LSU-rRNA Important in Cell Biology?
Maturation of LSU-rRNA is a critical step in ribosome biogenesis because the large ribosomal subunit cannot function without correctly processed LSU-rRNA. Defects in this process can impair translation and cell growth, and the pathway is a target for understanding fundamental cell biology and pathogen-specific mechanisms. Because LSU-rRNA maturation factors are conserved but can differ across lineages, studying GO:0000470 helps reveal both core and organism-specific requirements for ribosome assembly.
• Required for large ribosomal subunit assembly and protein synthesis.
• Disruption leads to defective ribosome biogenesis and impaired cell growth.
• Involved in pathogen biology, including trypanosomes and microsporidia.
• Shows lineage-specific mechanisms, such as segmented rRNA processing in trypanosomes.
• Provides a basis for annotating gene function in ribosome-related pathways.
• Relevant to plant development through NOL12-dependent rRNA processing.
• Can be studied using genetic complementation and RNA processing assays.
• Links to ribosome biogenesis stress and cellular homeostasis.
• Supports comparative studies of rRNA maturation across eukaryotes.
• Offers targets for functional genomics and CRISPR screening.
What Happens During maturation of LSU-rRNA?
Transcription and precursor formation
In simple terms: The cell first makes a long rRNA copy that contains the future LSU-rRNA plus extra spacer sequences.
LSU-rRNA is initially transcribed as part of a large precursor rRNA that includes external and internal transcribed spacers. In organisms such as Trypanosoma brucei, the LSU-rRNA is segmented and the precursor must be processed to generate mature segments. In Arabidopsis, the precursor rRNA requires processing factors such as NOL12 to proceed toward mature LSU-rRNA.
Endonucleolytic cleavage events
In simple terms: Enzymes cut the precursor rRNA at specific sites to separate the mature LSU-rRNA from spacers.
Endonucleolytic cleavages remove transcribed spacers and define the ends of the mature LSU-rRNA. In trypanosomes, a trypanosome-specific complex mediates late-stage processing of cytosolic LSU rRNA. In microsporidia, the identification of rRNA maturation sites argues against the full excision of the presumed ITS1 sequence, indicating variation in cleavage patterns.
Exonucleolytic trimming by RRP44
In simple terms: After cutting, other enzymes trim the ends to produce the exact mature rRNA.
The exonuclease RRP44 is involved in the maturation of segmented ribosomal RNA in Trypanosoma brucei, as shown using a regulated genetic complementation system. This suggests that exonucleolytic trimming is a key step in generating mature LSU-rRNA in some organisms.
Assembly with ribosomal proteins
In simple terms: The mature rRNA combines with proteins to build the large ribosomal subunit.
Once LSU-rRNA is matured, it assembles with ribosomal proteins to form the large ribosomal subunit. Defects in maturation prevent proper assembly and can lead to ribosome biogenesis stress.
Quality control and degradation
In simple terms: If processing fails, the cell can degrade faulty rRNA to avoid making broken ribosomes.
Quality control pathways monitor rRNA processing, and exosome-associated nucleases such as RRP44 can participate in degradation of improperly processed intermediates. This ensures that only correctly matured LSU-rRNA is used for ribosome assembly.
Key Genes Involved in GO:0000470 maturation of LSU-rRNA
The following genes and proteins have been experimentally linked to LSU-rRNA maturation or related rRNA processing steps in the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| RRP44 | Exonuclease involved in maturation of segmented ribosomal RNA in Trypanosoma brucei | Studied using regulated genetic complementation to dissect LSU-rRNA processing |
| NOL12 | Nucleolar protein required for processing of large ribosomal subunit rRNA precursors in Arabidopsis | Plant model for LSU-rRNA maturation and ribosome biogenesis |
| Trypanosome-specific complex components | Mediate late-stage processing of cytosolic LSU rRNA in trypanosomes | Lineage-specific LSU-rRNA maturation mechanism |
| ITS1 processing factors | Participate in internal transcribed spacer processing in microsporidia | Comparative rRNA maturation site identification |
| 26S rRNA maturation factors | Alternative post-transcriptional maturation of 26S rRNA in fungi | Fungal rRNA maturation diversity |
| LSU-rRNA processing factors in dinoflagellates | Related to syndinean dinoflagellate rRNA maturation | Comparative rRNA evolution |
| Diplonema mitochondrial LSU rRNA factors | Trans-splicing and RNA editing of LSU rRNA | Mitochondrial rRNA maturation mechanisms |
| Plasmodium LSU rRNA factors | Structure of large subunit rRNA in blood stages | Malaria parasite rRNA biology |
| Encephalitozoon cuniculi rRNA maturation factors | rRNA maturation sites in microsporidia | Microsporidian rRNA processing |
| Arabidopsis rRNA processing proteins | Pre-rRNA processing in plants | Plant ribosome biogenesis |
| Trypanosoma brucei exosome components | rRNA processing and degradation | Trypanosome ribosome biogenesis |
| Fungal 26S rRNA processing factors | Alternative maturation of 26S rRNA | Fungal rRNA processing |
| Dinoflagellate rRNA processing factors | Syndinean dinoflagellate rRNA maturation | Protist rRNA evolution |
| Microsporidian ITS1 processing factors | ITS1 sequence retention in rRNA maturation | Microsporidian rRNA maturation |
| Diplonema mitochondrial rRNA editing factors | RNA editing of LSU rRNA | Mitochondrial rRNA maturation |
| Plasmodium large subunit rRNA | LSU rRNA structure in blood stages | Plasmodium rRNA biology |
How Is maturation of LSU-rRNA Regulated?
LSU-rRNA maturation is regulated by the availability of processing factors and the assembly state of the ribosome. In Trypanosoma brucei, RRP44 function in segmented ribosomal RNA maturation was dissected using a regulated genetic complementation system, indicating that the level of this nuclease is critical for processing. In Arabidopsis, NOL12 is required for processing of large ribosomal subunit rRNA precursors, linking a nucleolar protein to the regulation of LSU-rRNA maturation. The process is also influenced by the structure of the precursor rRNA and the presence of lineage-specific complexes, as shown in trypanosomes. These findings suggest that LSU-rRNA maturation is controlled at the level of processing factor availability and precursor RNA recognition.
maturation of LSU-rRNA and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| RRP44 | Trypanosome ribosome biogenesis and viability | Trypanosoma brucei regulated genetic complementation |
| NOL12 | Plant growth and rRNA processing defects | Arabidopsis knockout or knockdown |
| Trypanosome-specific complex components | Late-stage LSU rRNA processing in trypanosomes | Trypanosome mutants and RNA processing assays |
| ITS1 processing factors | Microsporidian rRNA maturation | Encephalitozoon cuniculi comparative analysis |
| 26S rRNA maturation factors | Fungal rRNA processing diversity | Fungal model systems |
Ribosome biogenesis stress and cell growth defects
Defects in LSU-rRNA maturation can lead to impaired ribosome assembly and ribosome biogenesis stress, which affects cell growth and proliferation. Studies in Trypanosoma brucei and Arabidopsis show that loss of processing factors such as RRP44 or NOL12 disrupts rRNA maturation and downstream ribosome function.
Pathogen-specific rRNA maturation as a vulnerability
Trypanosomes and microsporidia have specialized LSU-rRNA maturation mechanisms, including segmented rRNA processing and unusual ITS1 retention. These differences may represent pathogen-specific vulnerabilities that could be explored for therapeutic targeting.
Comparative rRNA maturation and disease relevance
Alternative rRNA maturation pathways in fungi and other eukaryotes highlight how changes in LSU-rRNA processing can affect ribosome function. Understanding these variations can inform studies of ribosomopathies and other diseases linked to ribosome dysfunction.
From maturation of LSU-rRNA-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is RRP44 required for LSU-rRNA maturation? | Knockout or regulated knockdown in Trypanosoma brucei |
| Does NOL12 affect large ribosomal subunit rRNA processing? | Knockout in Arabidopsis |
| What is the role of a trypanosome-specific complex in LSU rRNA processing? | Knockout or tagged knock-in in Trypanosoma brucei |
| How do ITS1 processing sites vary in microsporidia? | Comparative sequence and processing site mapping |
| Is a candidate gene causally involved in LSU-rRNA maturation? | CRISPR knockout followed by rRNA processing assays |
| Can a point mutation in a processing factor alter LSU-rRNA maturation? | Point-mutation knock-in in a model organism |
How to Study the maturation of LSU-rRNA Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Northern blotting | Precursor and mature LSU-rRNA levels | Assessing processing defects in mutants |
| Primer extension | rRNA cleavage sites and ends | Mapping maturation sites |
| Regulated genetic complementation | Requirement of a gene for rRNA maturation | Conditional knockdown in trypanosomes |
| CRISPR knockout | Loss-of-function effects on LSU-rRNA maturation | Testing candidate genes |
| CRISPR knock-in | Effects of specific mutations or tags | Studying point mutations in processing factors |
| Comparative sequence analysis | Conservation of rRNA processing sites | Identifying lineage-specific maturation patterns |
| RNA-seq | Global changes in rRNA processing intermediates | Transcriptome-wide assessment of rRNA maturation |
RNA processing assays
RNA processing assays, such as northern blotting and primer extension, are used to detect precursor and mature LSU-rRNA species and to determine whether a gene is required for specific cleavage steps. In Trypanosoma brucei, regulated genetic complementation combined with RNA analysis revealed the role of RRP44 in segmented ribosomal RNA maturation.
Regulated genetic complementation
Regulated genetic complementation allows conditional expression of a gene to test its requirement for LSU-rRNA maturation. This approach was used to dissect RRP44 function in Trypanosoma brucei, showing that depletion affects rRNA processing.
Comparative genomics and rRNA mapping
Comparative analysis of rRNA maturation sites across organisms, such as microsporidia and fungi, helps identify conserved and lineage-specific processing patterns. These studies use sequence alignment and experimental mapping of rRNA ends.
CRISPR-based functional screens
CRISPR knockout and knock-in models can be used to test candidate genes for their role in LSU-rRNA maturation. By combining gene editing with rRNA processing assays, researchers can determine whether a gene is causally involved in the pathway.
How CRISPR Can Be Used to Study GO:0000470 maturation of LSU-rRNA
Knockout
CRISPR knockout can be used to delete candidate LSU-rRNA maturation genes and assess the consequences on rRNA processing and cell growth. For example, knocking out NOL12 in Arabidopsis would test its requirement for large ribosomal subunit rRNA precursor processing.
Point Mutation
Point-mutation knock-in can introduce specific amino acid changes in processing factors to dissect catalytic or interaction domains. This is useful for studying nucleases such as RRP44 and their role in LSU-rRNA maturation.
Knock-in
Tagged knock-in of processing factors allows localization and interaction studies in the context of LSU-rRNA maturation. For example, tagging a trypanosome-specific complex component can reveal its role in late-stage LSU rRNA processing.
Overexpression
Overexpression of LSU-rRNA maturation factors can test whether increased levels alter processing efficiency or rescue defects. This approach can be combined with RNA processing assays to quantify effects on precursor and mature rRNA.
How EDITGENE Supports maturation of LSU-rRNA Research
Researchers studying maturation of LSU-rRNA-related genes often need to determine whether a candidate gene is causally involved in rRNA processing, whether a specific mutation affects maturation, or whether overexpression changes the pathway. EDITGENE provides CRISPR-based cell models and screening services to address these questions with rigor and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for maturation of LSU-rRNA research.
Frequently Asked Questions About maturation of LSU-rRNA
What is maturation of LSU-rRNA (GO:0000470)?
It is the biological process that converts a precursor large subunit ribosomal RNA into a mature LSU-rRNA molecule, as defined by GO:0000470.
What genes are involved in maturation of LSU-rRNA?
Genes such as RRP44 and NOL12 have been experimentally linked to LSU-rRNA maturation in trypanosomes and plants, respectively.
Why is LSU-rRNA maturation important?
It is required for assembling the large ribosomal subunit and for protein synthesis; defects impair cell growth.
How is LSU-rRNA maturation studied?
Common methods include RNA processing assays, regulated genetic complementation, and CRISPR-based models.
Is LSU-rRNA maturation conserved across species?
The process is conserved in principle but shows lineage-specific features, such as segmented rRNA processing in trypanosomes.
What is the role of RRP44 in LSU-rRNA maturation?
RRP44 is an exonuclease involved in the maturation of segmented ribosomal RNA in Trypanosoma brucei.
What is the role of NOL12 in LSU-rRNA maturation?
NOL12 is a nucleolar protein required for processing of large ribosomal subunit rRNA precursors in Arabidopsis.
Can CRISPR be used to study LSU-rRNA maturation?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be combined with rRNA processing assays to test gene function.
What diseases are linked to LSU-rRNA maturation defects?
Defects can cause ribosome biogenesis stress and impaired cell growth; pathogen-specific mechanisms are also studied.
Where can I find CRISPR models for LSU-rRNA maturation research?
EDITGENE provides knockout, point-mutation, knock-in, overexpression, and screening services for genes in this pathway.
Conclusion
GO:0000470 maturation of LSU-rRNA is a fundamental biological process required for large ribosomal subunit assembly and protein synthesis. Research across trypanosomes, plants, fungi, and other eukaryotes has revealed both conserved and lineage-specific mechanisms, highlighting the importance of functional studies. CRISPR-based models and RNA processing assays provide powerful tools to dissect the genes and steps involved in this pathway. Understanding LSU-rRNA maturation will continue to inform ribosome biology and may reveal new targets in pathogen and disease research.
References
- 1. Amodeo S et al.. 2025. A trypanosome-specific complex mediates late-stage processing of cytosolic LSU rRNA.. Nucleic Acids Res 53(22) PMID: 41391488
- 2. Valach M et al.. 2014. Trans-splicing and RNA editing of LSU rRNA in Diplonema mitochondria.. Nucleic Acids Res 42(4):2660-72 PMID: 24259427
- 3. Navarro-Ródenas A et al.. 2018. Identification of an Alternative rRNA Post-transcriptional Maturation of 26S rRNA in the Kingdom Fungi.. Front Microbiol 9:994 PMID: 29887836
- 4. Peyretaillade E et al.. 2001. The identification of rRNA maturation sites in the microsporidian Encephalitozoon cuniculi argues against the full excision of presumed ITS1 sequence.. J Eukaryot Microbiol Suppl:60S-62S PMID: 11906080
- 5. Yoo J et al.. 2023. Syndinean dinoflagellates of the genus Euduboscquella are paraphyletic.. J Eukaryot Microbiol 70(2):e12953 PMID: 36301231
- 6. Guerra-Slompo EP et al.. 2023. Dissecting Trypanosoma brucei RRP44 function in the maturation of segmented ribosomal RNA using a regulated genetic complementation system.. Nucleic Acids Res 51(1):396-419 PMID: 36610751
- 7. Zakrzewska-Placzek M et al.. 2023. The nucleolar protein NOL12 is required for processing of large ribosomal subunit rRNA precursors in Arabidopsis.. BMC Plant Biol 23(1):538 PMID: 37919659
- 8. Waters AP et al.. 1995. The structure of the large subunit rRNA expressed in blood stages of Plasmodium falciparum.. Mol Biochem Parasitol 72(1-2):227-37 PMID: 8538692
