Cell envelope targets and schematic of cell envelope eSGA strategy.

(A) Schematic summary of the eSGA gene targets associated with the E. coli outer membrane (OM), inner membrane (IM), periplasm (PP), cytoplasm (CY), regulatory RNA (sRNA), or of uncertain localization. Gene numbers are indicated, with essential genes shown in brackets. (B) Functional distribution of annotated (Group 1), uncertain function (Group 2) and predicted (Group 3) envelope target genes sorted into 20 broadly representative bioprocesses. (C) Schematic summarizing the experimental construction and computational analysis of two E. coli cell-envelope genetic interaction maps. After conjugation and genetic exchange, high density arrays of double-mutants were first selected on rich medium containing Cm and Kan. After outgrowth for 24 hours, surviving colonies were then replica pinned onto minimal M9 medium, to identify condition-dependent genetic interactions. Both sets of plates were digitally imaged and colony sizes quantified to determine gene pairs showing aggravating (synthetic lethal and synthetic sick) and alleviating (buffering) interactions.