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Schutz zellfremder DNA vor wirtskontrollierter Restriktion in Bakterienzellen. II. Schutz des Plasmids pSF2124 durch die ocr + Genfunktion der Bakteriophagen T3 und T7
Author(s) -
Reuter Monika,
Krüger D. H.,
Scholz D.,
Rosenthal H. A.
Publication year - 1980
Publication title -
zeitschrift für allgemeine mikrobiologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0044-2208
DOI - 10.1002/jobm.19800200506
Subject(s) - plasmid , microbiology and biotechnology , biology , transformation (genetics) , dna , phagemid , mutant , gene , escherichia coli , restriction site , restriction enzyme , genetics , bacteriophage
When restriction‐active Escherichia coli cells (r P1 + m + P1 ) are transformed with the pSF2124 plasmid, a common vector in experimental gene transfer, the efficiency of transformation (e.o.t.) is lowered by 2 orders of magnitude compared with restriction‐negative (r P1 − m P1 −or r P1 − m P1 − ) recipient cells due to restriction of the pSF2124 DNA by endoR. Eco P1. Preinfection of r P1 + m P1 +cells with UV‐inactivated ocr + phages (T3, T7, T3 sam − ) still able to express their early genes protects the plasmid DNA against restriction by endoR. Eco P1: The e.o.t. of r P1 + m P1 +recipient cells with pSF2124 attains the same high value as that of r − m − cells. The specific role of the ocr + gene function was demonstrated by the use of ocr − mutants (T3/R7, T7/ D111): Preinfection with such phage mutants does not increase the e.o.t. of r P1 + m P1 +cells. An unspecific e.o.t. alteration of restriction‐negative (r − m − ) recipient cells by ocr + or ocr − phages was excluded. The ocr − gene function can be exploited to protect pSF2124 against DNA restriction. The recipient cells survive the process of phage preinfection and transformation and stably replicate themselves as well as the plasmid DNA.