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Transcription And Translation Of R-plasmid 538-1 DNA: Effects Of Mercury Induction And Analysis Of Polypeptides Coded For By The R-determinant Region.
Published 1979 · Biology, Medicine
Abstract In vivo transcription and translation of R-plasmid 538-1 in Escherichia coli was analyzed. Transcription of individual restriction fragments was determined qualitatively by utilizing the techniques developed by Southern J. Mol. Biol. 98, 503–517, 1975 and quantitatively by carrying out DNA-RNA filter hybridization. The most active region of R-plasmid transcription in strains repressed for conjugal transfer was found to occur in the region of the R-plasmid carrying the antibiotic resistance genes. In plasmids derepressed for conjugal transfer, a high level of transcription from the transfer gene region was also observed. When strains carrying R538-1 were induced with Hg2+ a high level of transcription was observed from the region of the R-plasmid carrying the genes for Hgr. Hybrid ColE1 plasmids carrying restriction fragments from the antibiotic resistance region of R538-1 were segregated into minicells. Labeling of the minicells with [35S]methionine or [14C]amino acids allowed identification of the proteins coded by the fragments. A limited number of proteins were detected, and several of these have been correlated with the antibiotic resistance genes carried by R538-1.