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Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry
Published on: June 26, 2019
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Human nucleolar protein 7 (NOL7) is required for early pre-rRNA accumulation and pre-18S rRNA processing
Mason A McCool1, Carson J Bryant1, Hannah Huang1
1Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA.
RNA Biology
|May 29, 2023
Summary
Human NOL7 is an essential U3 Associated Protein (UTP) required for early pre-ribosomal RNA (pre-rRNA) accumulation and processing, impacting protein synthesis and nucleolar stress.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Eukaryotic ribosome biogenesis is a conserved, essential cellular process.
- U3 Associated Proteins (UTPs) are crucial for early ribosome biogenesis steps.
- Human homologs for yeast Utp9 and Bud21 (Utp16) were previously unidentified.
Purpose of the Study:
- Identify the human ortholog of yeast Bud21 (Utp16).
- Investigate the role of the identified human ortholog in ribosome biogenesis.
- Determine the functional significance of this protein in human cells.
Main Methods:
- Comparative genomics to identify protein orthologs.
- Depletion studies using siRNA in human cells.
- Analysis of pre-ribosomal RNA (pre-rRNA) levels and processing intermediates.
- Assessment of protein synthesis rates.
- Monitoring of nucleolar stress response markers.
Main Results:
- NOL7 identified as the likely human ortholog of yeast Bud21.
- NOL7 depletion impairs early pre-rRNA accumulation and pre-18S rRNA processing.
- Loss of NOL7 function reduces overall protein synthesis.
- NOL7 depletion induces a nucleolar stress response in human cells.
- Human NOL7 is essential, unlike the nonessential yeast Bud21.
Conclusions:
- Human NOL7 is an essential UTP critical for ribosome biogenesis.
- NOL7 plays a vital role in maintaining pre-rRNA levels and processing.
- NOL7 functions are essential for cellular homeostasis and preventing nucleolar stress.
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