Lentiviral Transduction of the sgRNA Library

L02 cells were purchased from ATCC, and cultured in DMEM (Gibco), supplemented with FBS 10% (Invitrogen, United States). Gecko library was used to infect 3 × 10⁸ cells. The multiplicity of infection (MOI) was 0.1, and aimed to ensure that most cells received only 1 viral construct. The culture medium containing cells was supplemented with 10% FBS and 4 mM l- glutamic acid (Invitrogen), 10 μg/ml penicillin and streptomycin (Invitrogen, United States), followed by addition of the lentivirus to each dish with 8 μg/mL polybrene (Sigma). The cultures were incubated for 48 h, medium aspirated out, replaced with fresh DMEM supplemented with 1 μg/ml doxycycline, followed by incubation for 7 days. The cell population was created, with each target gene theoretically carrying a mutation of functional loss (Figure 1A, ​,2)2) (Wang et al., 2014b).

KEGG pathway (A) and GO enrichment (B) analyses of the top-ranked PM_2.5 resistance genes with high number (4–6) of unique sgRNAs. Significant processes and pathways are depicted in red. BP, GO Biological Process; MF, GO Molecular Function; CC, GO Cellular Component).