Cip1 and Cip2 are novel RNA-recognition-motif proteins that counteract Csx1 function during oxidative stress

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Eukaryotic cells alter gene expression in response to stress.
• The RNA-binding protein Csx1 is crucial for oxidative stress response in Schizosaccharomyces pombe.
• Csx1 stabilizes atf1(+) mRNA, essential for oxidative stress gene expression.

Purpose of the Study:

• Identify novel proteins interacting with Csx1.
• Investigate the function of Cip1 and Cip2 in oxidative stress response.
• Elucidate the interplay between Csx1, Cip1, and Cip2 in posttranscriptional regulation.

Main Methods:

• Multidimensional protein identification technology (MudPIT) for protein identification.
• Genetic epistasis studies to determine genetic interactions.
• Whole genome expression profiling to analyze gene expression changes.
• Analysis of cellular morphology and growth rates.

Main Results:

• Cip1 and Cip2 were identified as Csx1-interacting proteins.
• Cip1 and Cip2 are cytoplasmic proteins with RNA recognition motifs (RRMs).
• Loss of Cip1 and Cip2 leads to poor growth and altered morphology.
• Cip1 and Cip2 negatively regulate gene expression, counteracted by Csx1.
• Mutations in cip1 and cip2 partially rescue the oxidative stress sensitivity of csx1Δ cells.

Conclusions:

• Cip1 and Cip2 play a significant role in posttranscriptional control of gene expression during oxidative stress.
• The balance between Csx1 and Cip1/Cip2 activity is critical for modulating mRNA stability and cellular response to stress.
• This study highlights the complex regulatory network involving RNA-binding proteins in eukaryotic stress response pathways.