Related Experiment Video
Updated: Mar 3, 2026
07:35
Analysis of Spliceosomal snRNA Localization in Human Hela Cells Using Microinjection
Published on: August 6, 2019
6.5K
Reconstitution of a functional 7SK snRNP
John E Brogie1, David H Price1
1Biochemistry Department, University of Iowa, Iowa City, IA 52242, USA.
Nucleic Acids Research
|April 22, 2017
Summary
The 7SK small nuclear ribonucleoprotein (snRNP) structure and folding dynamics were elucidated, revealing how it regulates RNA polymerase II. This research details intramolecular interactions within the 7SK snRNP complex.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- The 7SK small nuclear ribonucleoprotein (snRNP) is crucial for regulating RNA polymerase II elongation.
- It controls the availability of active P-TEFb, a key component in transcription.
Purpose of the Study:
- To optimize conditions for analyzing 7SK RNA structure and folding dynamics.
- To investigate the role of magnesium in 7SK folding.
- To elucidate the structural mechanisms of 7SK snRNP assembly and function.
Main Methods:
- Selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) to probe RNA structure.
- In vitro reconstitution of the 7SK snRNP complex using recombinant proteins (P-TEFb, HEXIM1, LARP7, MEPCE).
- Analysis of protein-RNA interactions and functional assays.
Main Results:
- Optimized SHAPE conditions revealed magnesium-dependent folding dynamics and a GAUC motif switch in 7SK RNA.
- Identified open and closed forms of 7SK RNA based on alternative 5' end pairing.
- In vitro reconstituted 7SK snRNP showed inhibited P-TEFb, which could be released by HIV-1 Tat.
- P-TEFb binding induced similar structural changes in both reconstituted and cellular 7SK snRNPs.
- LARP7's xRRM domain binds the 7SK 3' stem loop and inhibits MEPCE activity via its C-terminal MID, dependent on 7SK structure.
Conclusions:
- The 7SK snRNP undergoes P-TEFb-dependent structural changes.
- LARP7 inhibits MEPCE activity through specific interactions with the 7SK RNA structure.
- This study provides critical insights into the intramolecular interactions governing 7SK snRNP function.
Related Concept Videos
01:32RNA Splicing
61.0K
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
61.0K
02:53Ribosomal RNA Synthesis
15.0K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
15.0K
02:53Ribosomal RNA Synthesis
4.6K
4.6K
02:37Restarting Stalled Replication Forks
6.5K
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart,...
6.5K
03:01The Replisome
38.9K
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with...
38.9K
02:36RNA Polymerase II Accessory Proteins
4.1K
4.1K