UCSF

© 2015 Elsevier Inc. Finding the components of cellular circuits and determining their functions systematically remains a majorchallenge in mammalian cells. Here, we introduced genome-wide pooled CRISPR-Cas9 libraries into dendritic cells (DCs) to identify genes that control the induction of tumor necrosis factor (Tnf) by bacterial lipopolysaccharide (LPS), a key process in the host response to pathogens, mediated by the Tlr4 pathway. We found many of the known regulators of Tlr4 signaling, as well as dozens of previously unknown candidates that we validated. By measuring protein markers and mRNA profiles in DCs that are deficient in known or candidate genes, we classifiedthe genes into three functional modules with distinct effects on the canonical responses to LPS and highlighted functions for the PAF complex and oligosaccharyltransferase (OST) complex. Our findings uncover new facets of innate immune circuits in primary cells and provide a genetic approach for dissection of mammalian cell circuits. A protein marker-based, genome-wide CRISPR screen has been developed in primary immune cells to identify genes that control the induction of tumor necrosis factor. Many of the known regulators, as well as dozens of previously unknown candidates, have been identified, individually validated, and classified into three functional modules.