Transfer of RP4::Mu plasmids from K12 to EBF65/65 was very inefficient compared with RP4 and was only detectable to strains of EBF65/65 lacking pAV2, a cryptic plasmid thought to code for a restriction/modification system. RP4::Mu-derived plasmids transferred from pAV2strains of EBF65/65 back to K12 were found to carry defective prophages which had lost the ability to produce detectable phage particles. Re-transfer of these defective plasmids from and strains of K12 back to EBF65/65, when compared with the transfer of RP4, provided evidence for a second restriction/modification system in EBF65/65 which affected mainly Mu DNA. Using a mutant Mu prophage, Mu , it was possible to obtain RP4::Mu plasmids in EBF65/65 which were non-defective. These produced viable Mu particles when transferred back to K12 and could also be thermoinduced in EBF65/65; however, expression of Mu in EBF65/65 was very poor and plaques were only detected on a restrictionless strain of K12. ‘Plasmid suicide by Mu’ may enable the development of a method for directed chromosome mobilization in


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error