Clear Plaque Mutants of Lactococcal Phage TP901-1.
We report a method for obtaining turbid plaques of the lactococcal bacteriophage TP901-1 and its derivative TP901-BC1034. We have further used the method to isolate clear plaque mutants of this phage. Analysis of 8 such mutants that were unable to lysogenize the host included whole genome resequencing. Four of the mutants had different mutations in structural genes with no relation to the genetic switch. However all 8 mutants had a mutation in the cI repressor gene region. Three of these were located in the promoter and Shine-Dalgarno sequences and five in the N-terminal part of the encoded CI protein involved in the DNA binding. The conclusion is that cI is the only gene involved in clear plaque formation i.e. the CI protein is the determining factor for the lysogenic pathway and its maintenance in the lactococcal phage TP901-1.
Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark.
Witold
W
Kot
Department of Systems Biology, The Technical University of Denmark, Matematiktorvet Building 301, DK-2800, Lyngby, Denmark.
Mogens
M
Kilstrup
Department of Food Science, University of Copenhagen, Rolighedsvej 26, DK-1958, Frederiksberg C, Denmark.
Finn K
FK
Vogensen
Department of Systems Biology, The Technical University of Denmark, Matematiktorvet Building 301, DK-2800, Lyngby, Denmark.
Karin
K
Hammer
D001435:Bacteriophages / Q000235:genetics*; D004279:DNA, Viral; D017045:Lactococcus / Q000821:virology*; D009154:Mutation; D011401:Promoter Regions, Genetic; D014764:Viral Proteins / Q000235:genetics*
D004279:DNA, Viral; D014764:Viral Proteins