The GreenScreen genotoxicity assay: a screening validation programme.
A yeast (Saccharomyces cerevisiae) DNA repair reporter assay termed the GreenScreen assay (GSA) is described. This is a novel, cost-effective genotoxicity screen, developed to provide a pre-regulatory screening assay for use by the pharmaceutical industry and in other applications where significant numbers of compounds need to be tested. It provides a higher throughput and a lower compound consumption than existing eukaryotic genotoxicity assays and is sensitive to a broad spectrum of mutagens and, importantly, clastogens. We describe a simple, robust assay protocol and a validation study. The end-point of the test reflects the typically eukaryotic chromosomes and DNA metabolizing enzymes of yeast. The capacity for metabolic activation (MA) in yeast is limited compared with the mammalian liver or its extracts, but the assay does detect a subset of compounds that would require MA in existing genotoxicity tests. The GSA detects a different spectrum of compounds to bacterial genotoxicity assays and thus, together with an in silico structure-activity relationship (SAR) screen, and possibly a high throughput bacterial screen, would provide an effective preview of the regulatory battery of genotoxicity tests.
Department of Biomolecular Sciences, UMIST, Manchester M60 1QD, UK.
P A
PA
Cahill
A W
AW
Knight
N
N
Billinton
M G
MG
Barker
L
L
Walsh
P O
PO
Keenan
C V
CV
Williams
D J
DJ
Tweats
R M
RM
Walmsley
D004265:DNA Helicases; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004843:Epistasis, Genetic; D017930:Genes, Reporter; D005821:Genetic Techniques; D009152:Mutagenicity Tests; D009153:Mutagens; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology
D009153:Mutagens; D029701:Saccharomyces cerevisiae Proteins; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D045643:DNA Repair Enzymes