Related Experiment Video
Updated: Jul 17, 2026
07:31
ACT1-CUP1 Assays Determine the Substrate-Specific Sensitivities of Spliceosomal Mutants in Budding Yeast
Published on: June 30, 2022
A spliceosome-independent eukaryote generated by complete intron removal.
Xin Man1, Wen-Ting Zhang1, Yu-Di Zhang1
1State Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
Cell
|July 15, 2026
Summary
Scientists created the first intron-free yeast, demonstrating eukaryotes can survive without spliceosomes. This breakthrough resolves the spliceosome
Area of Science:
- Molecular Biology
- Genomics
- Cell Biology
Background:
- Spliceosomal introns present a processing challenge for eukaryotes and hinder genome minimization.
- The essentiality of spliceosomal introns has remained an unresolved question in eukaryotic biology.
Purpose of the Study:
- To investigate the essentiality of spliceosomal introns by creating a completely intron-free eukaryotic cell.
- To determine if a eukaryotic cell can survive and function independently of the spliceosome.
Main Methods:
- Utilized Spo11-independent meiosis in a synthetic single-chromosome Saccharomyces cerevisiae strain.
- Achieved complete deletion of all 300 spliceosomal introns, generating an intron-free strain (SYNE27α).
- Confirmed intron excision via whole-genome sequencing and assessed spliceosomal component requirements for viability.
Main Results:
- Generated the first viable intron-free eukaryotic strain, SYNE27α.
- Demonstrated that spliceosomal components (snRNAs, Prp8, Prp9, Prp19, Yhc1, Luc7) are non-essential for viability.
- Observed U3 small nucleolar RNA (snoRNA) splicing bypasses requirements for specific spliceosomal factors (Yhc1, Luc7, Prp9, Prp19).
- Identified slow growth in the intron-free strain due to ribosomal dysregulation, with full genetic stability maintained.
- Confirmed intron loss as the primary driver of fitness costs, which were recessive in diploids.
Conclusions:
- Established the first intron-free, spliceosome-independent eukaryote, resolving the essential function of the spliceosome.
- Provides a minimal eukaryotic system for studying genome evolution and the impact of intron loss.
- Reveals mechanistic divergence in U3 snoRNA splicing compared to pre-mRNA splicing.
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...
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...
02:18Alternative RNA Splicing
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
02:18Alternative RNA Splicing
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
01:32Pre-mRNA Processing: RNA 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...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...