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The perinucleolar compartment and transcription
S Huang1, T J Deerinck, M H Ellisman
1Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA. s-huang2@nwu.edu
The Journal of Cell Biology
|October 8, 1998
Summary
The perinucleolar compartment (PNC) is a dynamic nuclear structure involved in RNA metabolism. Br-UTP incorporation indicates transcription by RNA polymerases II and/or III, and the PNC contains poly(A) RNA and pre-mRNA processing factors.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The perinucleolar compartment (PNC) is a distinct nuclear structure located near the nucleolus.
- Previous studies identified small RNAs and hnRNP proteins within the PNC.
Purpose of the Study:
- To investigate the transcriptional activity and functional role of the perinucleolar compartment (PNC).
- To determine the involvement of RNA polymerases in PNC nucleotide incorporation.
- To characterize the dynamic nature and molecular composition of the PNC.
Main Methods:
- Pulse labeling with Br-UTP and FITC-conjugated CTP to assess nucleotide incorporation.
- Selective inhibition of RNA polymerases I, II, and III using specific inhibitors and actinomycin D.
- Double labeling experiments and Fluorescence Recovery After Photobleaching (FRAP) analysis.
Main Results:
- The PNC actively incorporates nucleotides, indicating active transcription by RNA polymerases II and/or III.
- Inhibition of RNA polymerase II and III significantly reorganizes the PNC structure.
- The PNC contains poly(A) RNA and pre-mRNA processing factors, with rapid turnover of polypyrimidine tract binding protein.
Conclusions:
- The PNC is a dynamic nuclear compartment actively involved in RNA metabolism.
- The findings suggest a role for the PNC in transcription and pre-mRNA processing.
- The PNC's dynamic nature is crucial for its function within the cell nucleus.