Selective defects in gene expression control genome instability in yeast splicing mutants.

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• RNA processing, particularly splicing, is crucial for genome stability.
• Two main models explain this link: altered gene expression and R-loop formation.
• Mechanistic details connecting splicing defects to genome instability remain unclear.

Purpose of the Study:

• To investigate genome instability phenotypes in yeast splicing factor mutants.
• To elucidate the mechanistic links between splicing defects and genome instability.
• To identify factors that modify these phenotypes.

Main Methods:

• Characterization of genome instability in yeast splicing factor mutants.
• Analysis of R-loop accumulation and mitotic defects.
• Assessment of gene expression alterations and cis effects.
• Evaluation of the role of the spindle-assembly checkpoint protein Mad1.
• Genetic manipulation, including intron removal from the TUB1 gene.

Main Results:

• Splicing factor mutants exhibit genome instability, primarily via mitotic defects and sometimes R-loop accumulation.
• Altered gene expression, rather than direct cis effects, contributes significantly to instability.
• Loss of Mad1 exacerbates genome instability in these mutants.
• Removing the intron from the TUB1 gene rescues genome integrity.

Conclusions:

• Genome instability in splicing mutants arises from multiple pathways, including altered gene expression and R-loops.
• The spliceosome's conditional mutants display diverse phenotypes due to varying transcriptomic effects.
• Mad1 and intron removal highlight specific genetic interactions influencing genome stability in splicing mutants.