Detection of environmental mutagens using the FACIM assay

Area of Science:

• Environmental Science
• Genetics
• Toxicology

Background:

• Environmental monitoring requires sensitive methods for detecting mutagens.
• Existing assays like SOS Chromotest have limitations in detecting direct-acting mutagens.
• The TP53 gene is a critical tumor suppressor, and its mutation is a key indicator of mutagenic activity.

Purpose of the Study:

• To develop and validate a genetically engineered yeast strain (yJC2) for environmental mutagen detection.
• To characterize the sensitivity and inducibility of the new assay (FACIM II) compared to existing methods.
• To assess the utility of FACIM II for detecting mutations induced by various mutagens.

Main Methods:

• Development of a diploid yeast strain (yJC2) with human TP53 gene and ADE2 reporter genes.
• Exposure of yJC2 cells to known mutagens (UVC, 4-nitroquinoline NQO) and environmental samples (Seine estuary sediment extract).
• Measurement of TP53 transcriptional activity and mutant frequency to assess mutagenic effects.

Main Results:

• The yJC2 strain demonstrated a significant, dose-dependent increase in mutant frequency upon exposure to UVC, NQO, and sediment extract.
• The FACIM II assay showed high sensitivity in detecting mutagenic activity in environmental samples.
• FACIM II proved more convenient and inducible than FACIM I and SOS Chromotest, respectively.

Conclusions:

• The FACIM II assay, utilizing the yJC2 yeast strain, is a powerful and convenient tool for environmental mutagen detection.
• This assay enables accurate measurement of TP53 transcriptional activity, serving as a reliable biomarker for mutagenicity.
• FACIM II offers an improved method for characterizing induced mutations and assessing environmental genotoxicity.