ludwig@ORCHID.UCSC.EDU (Bob Ludwig) (07/30/90)
"The E. coli SURE strain carries a copy of the Tn5 element." I've had a number of requests to elaborate on this message. Tn5 is a bacterial transposable element conferring resistance to kanamycin and streptomycin (requires a mutation to do so in E. coli). It transposes to new DNA loci at a frequency of 10 exp -5 per cell-generation. Therefore, recombinant DNA work with kanamycin phosphotransferase genes is excluded in SURE. Furthermore, any use of SURE as host for recombinant DNA runs the risk that Tn5 will transpose to these sequences. -Bob Ludwig