Figure 2. Identification of E. coli mutants in the Keio library defective in recovery of Mu::Cm insertions.

(A) Functional map of the Mu genome packaged within a phage particle, showing position of inserted Cm^R cassette, and host or flap DNA attached to both ends. The SE (semi-essential) region contains 14 orfs [27]; only those assigned a phenotype/function are indicated [2]. (B) Cultures infected with Mu::Cm were spotted on Cm plates as described in Methods. Control panel: Expected results from infection of two different wild type and their derivative mutant strains - clpX and himA - that do not support Mu replication. Bottom four panels: Final set of mutants from the Keio screen showing lower Mu::Cm lysogen recovery compared to the wild type strain, grouped into indicated categories.