Fig. 1: A CRISPR-Cas9 screen to identify genes that are responding to formaldehyde.

a Schematic overview of the formaldehyde CRISPR-Cas9 screen. In brief, RPE-1 cells were infected by the TKO_V1 lentiviral library, followed by puromycin selection and amplification. Infected cells were continuously treated with or without 70 µM formaldehyde and genomic DNA extraction was carried out on day 9 and day 15 post-treatment. Next-generation sequencing results were analyzed with DrugZ²⁶. NT: untreated cells. b Normalized gene-level Z-scores (normZ score) for genes that appeared in results from the negative selection of the CRISPR-Cas9 screen. The dashed line corresponds to the significance threshold (−3 represents a probability value of less than 0.001). Genes in blue belong to the FA pathway, in green to formaldehyde catabolic process and EXO1 is in red. c Gene ontology of biological processes corresponding to genes targeted by sgRNA that are significantly decreased after formaldehyde treatment presented by DAVID software. The size of the circle is proportional to the number of genes identified by the screen included in the indicated biological processes. FDR false discovery rate.