Related Experiment Video
Updated: Aug 12, 2026
08:12
Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker
Published on: January 3, 2019
Yeast U1 snRNP-pre-mRNA complex formation without U1snRNA-pre-mRNA base pairing
1Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02454, USA.
RNA (New York, N.Y.)
|February 24, 2001
Summary
The U1 small nuclear ribonucleoprotein (snRNP) complex can recognize pre-mRNA 5' splice sites even without direct RNA-RNA base pairing. Protein factors within the U1 snRNP appear crucial for initial splice site recognition, with base pairing contributing to complex stability.
Area of Science:
- Molecular Biology
- RNA Biology
- Biochemistry
Background:
- Spliceosome assembly initiates with the recognition of pre-mRNA 5' splice sites.
- Base pairing between U1 small nuclear RNA (snRNA) and the pre-mRNA 5' splice site is considered critical for commitment complex formation.
- The precise mechanisms of initial pre-mRNA recognition by the splicing machinery remain incompletely understood.
Purpose of the Study:
- To investigate the role of RNA-RNA base pairing between U1 snRNA and the pre-mRNA 5' splice site in initial recognition.
- To determine the contribution of U1 snRNP protein factors in splice site selection.
Main Methods:
- Truncation of U1 snRNA to abolish RNA-RNA base pairing interaction.
- Analysis of U1 small nuclear ribonucleoprotein (snRNP) complex formation and sequence specificity with truncated U1 snRNA.
- Evaluation of multiple interaction sets contributing to complex stability.
Main Results:
- U1 snRNP formed a near-normal RNA-protein complex and maintained sequence specificity even when U1 snRNA was truncated to eliminate base pairing.
- Protein components of U1 snRNP, rather than base pairing, appear to be more important for initial 5' splice site recognition.
- At least five sets of interactions contribute to complex formation and stability, with base pairing being one of them.
Conclusions:
- Initial 5' splice site recognition by the splicing machinery may rely more heavily on U1 snRNP protein factors than on direct RNA-RNA base pairing.
- While base pairing contributes to the stability and conformation of the U1 snRNP-pre-mRNA complex, it is not essential for initial recognition or sequence specificity.
Related Concept Videos
01:32RNA Splicing
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...
02:01pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
02:01Pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
02:41Chromatin Structure Regulates pre-mRNA Processing
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...
02:53Ribosomal RNA Synthesis
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,...
01:25Nucleic Acid Structure
The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA has a double-helix structure. The...
DNA Structure
DNA has a double-helix structure. The...