Inability to utilize xylose. Allows cloning of DNA without cleavage by endogenous restriction endonucleases. E. coli hosts. Allows cloning of DNA without cleavage by endogenous restriction endonucleases . DNAprepared from hosts with this marker is unmethylated by the hsd S20 modificationsystem.
Mutation also prevents McrF restriction of methylated cytosine sequences.
Kanamycin resistance Tetracycline resistance Streptomycin resistance Indicates a deletion of genes following it. DNA Cloning, Vol. USA 83, 9070-9074. M13 transformation, grow on minimal medium to maintain F episome, grows well in 2x TY, plate on TY or lambda agar. Gene 33, 103-119.