Molecular mechanism of the specialized transducing bacteriophage lambda plac5 formation has been studied. Phage-bacterial DNA junctions in lambda plac5 DNA are localized and primary structure of regions of the abnormal excisional recombination leading to the phage formation is elucidated; the crossover region proved to be comparable with the central part of attP and attB sites (the core and the adjacent tetranucleotide) in length and degree of homology. Bacterial insert in lambda plac5 DNA is shown to end immediately after Z-Y spacer, the DNA not containing lacY gene segments. The data obtained led to the conclusion of site-specific (homologous) character of abnormal excision upon formation of lambda transducing bacteriophages. Possible mechanisms of the excision are discussed.
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http://dx.doi.org/10.1093/nar/12.17.6779 | DOI Listing |
Genet Res
June 1992
Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Recombination between F42lac and lambda plac5 is typically 20- to 50-fold more efficient than recombination between chromosomal lac and lambda plac5. This enhancement of recombination is recBCD-dependent and requires the expression of genes from the tra regulon of the F factor. Also required is oriT, the origin of F factor conjugational transfer, which must be located in-cis to the cellular copy of lac.
View Article and Find Full Text PDFJ Bacteriol
February 1991
Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Recombination between F42lac and lambda plac5 is typically 20- to 50-fold more efficient than recombination between chromosomal lac and lambda plac5. This enhancement of recombination requires trans-acting factors located in the promoter-distal and promoter-proximal regions of the main traY-to-traI (traZ) operon. By testing the ability of deletion mutants of tra to support enhanced recombination, we have identified traY as the only product has been ruled out.
View Article and Find Full Text PDFMol Gen Genet
February 1990
Institute of Medical Science, University of Tokyo, Japan.
A system for detecting a spontaneous deletion in Escherichia coli was developed and the role of DNA gyrase in deletion formation was studied. A derivative of lambda plac5, lambda AM36, was isolated in which whole pBR322 DNA was inserted in the lacZ gene and 227 bp of the lac gene duplicated at both sides of the pBR322 DNA. E.
View Article and Find Full Text PDFFEBS Lett
November 1989
Institute of Bioorganic Chemistry, Byelorussian SSR Academy of Sciences, Minsk.
In studying molecular mechanisms of the formation of transducing bacteriophages, we have elucidated the primary structure of the phage-bacterial DNA junction which resulted from the abnormal excision of the lambda plac10 phage. The process is structurally similar to the excision of the lambda plac5 phage and involves, in both cases, highly homological DNA stretches approximately 20 bp long, one of them being a part of the Z-Y spacer of the lac operon and possessing a developed secondary structure. The conception of regioselective recombination as a type of illegitimate recombinational process with a certain degree of site-specificity is suggested.
View Article and Find Full Text PDFInvestigating molecular mechanism of illegitimate recombinations in prokaryote we study transducing bacteriophages of the lambda lac series. We have carried out physical mapping of bacteriophage lambda plac9 DNA and, by comparing the obtained results with the data on the structure of lambda DNA and lac operon of E. coli, located the phage-bacterial junction corresponding to the lambda-lac9 abnormal excision and elucidated the nucleotide sequence around the junction.
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