UV Laser-Induced, Time-Resolved Transcriptome Responses of Saccharomyces cerevisiae

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Long-wavelength UV irradiation can induce cellular stress.
• Understanding the transcriptional response to UV damage is crucial for cell biology.

Purpose of the Study:

• To determine the effect of laser-mediated, long-wavelength UV irradiation on gene transcription in *Saccharomyces cerevisiae*.
• To identify unique transcriptional responses to UV laser irradiation beyond known environmental stress response genes.

Main Methods:

• RNA sequencing (RNAseq) analysis was performed at 15, 30, and 60 minutes post-irradiation.
• Stringent statistical cut-offs (P < 0.05, log2 difference >2) were applied to identify differentially expressed genes.
• Environmental stress response (ESR) genes were filtered out to identify unique UV responses.

Main Results:

• Over 400 genes showed differential expression at 15 or 30 minutes, returning to basal levels by 60 minutes.
• Unique UV-responsive genes included those involved in amino acid metabolism (sulfur amino acids), sulfur regulation, proteasome components, and the iron regulon.
• At 30 minutes, a shift towards catabolic processes (oxidoreductase, peptidase activity) and UV damage response genes was observed. Down-regulation of tRNA genes suggested a control of protein biosynthesis.

Conclusions:

• Yeast exhibits a transient but significant transcriptional response to UV laser irradiation.
• The response involves amino acid and sulfur metabolism, protein catabolism, and regulation of protein biosynthesis.
• This study reveals specific gene expression patterns unique to UV laser insult, demonstrating yeast's adaptive capabilities.