Open AccessThe Early Region of the DNA of Bacteriophage T7
Author(s) -
Scherzinger Eberhard,
Herrlich Peter,
Schweiger Manfred,
Schuster Heinz
Publication year - 1972
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1972.tb01702.x
Subject(s) - microbiology and biotechnology , biology , rna dependent rna polymerase , polymerase , rna polymerase , t7 rna polymerase , rna polymerase i , small nuclear rna , dna polymerase i , rna editing , rna , dna polymerase , dna polymerase ii , dna , bacteriophage , gene , biochemistry , escherichia coli , reverse transcriptase
RNA polymerase from Escherichia coli transcribes on T7 DNA in vitro and in vivo a polycistronic messenger RNA of 2.2 × 10 6 molecular weight. This mRNA contains the information for synthesis of T7‐phage RNA polymerase, ligase and lysozyme as was demonstrated by enzyme synthesis in vitro , using the RNA synthesized in vitro as template. Bystudying the kinetics of synthesis of these enzymes in vitro and the ultraviolet‐irradiation sensitivity of enzymesynthesis rates in vivo , the location of the genes on the DNA was estimated. Phage RNA polymerase is encoded within the first half of the mRNA molecule. The information for ligase ends at approximately 5500 nucleotides (1.7 × 106 mol wt.) and the information for lysozyme is close to the 3′‐end of the mRNA. The genes for T7 RNA polymerase and ligase are transcribed by the host RNA polymerase (early region), whereas the genes for endonuclease (gene 3) and for lysozyme are read by E. coli RNA polymerase and by T7‐phage RNA polymerase (early/late region). The DNA beyond the termination signal for host RNA polymerase is transcribed by T7‐phage RNA polymerase in the late phase (late region). Genetic mapping of mutants in the ligase and in the lysozyme genes confirm the data obtained by enzyme synthesis in vitro.