One of Hera’s strategies to improving screening methodologies for toxic compounds is to examine the changes in patterns of toxicant-responsive gene expression. We use gene editing technologies to precisely replace the endogenous loci with easily assayed reporter genes thereby capturing the complete genomic context of the target gene expression which is analyzed in a high-throughput or high content system. These changes in gene expression are potentially more sensitive than cytotoxicity assays currently used since gene expression changes occur before enough damage has been done to cause toxicity. Toxicity reporter screens can be run on disease models or patient specific cell lines. Utilizing these technologies and methods our reporter cell lines are cost-effective, rapid systems for toxicity testing and improved tools for screening services.