Journal ArticleDOI
Polar mutations in lac, gal and phage λ consist of a few IS-DNA sequences inserted with either orientation
Reads0
Chats0
TLDR
It was found that many insertions which often arise as strongly polar mutations consist of only a few “foreign” DNA sequences.Abstract:
It was found that many insertions which often arise as strongly polar mutations consist of only a few “foreign” DNA sequences. The most commonly observed “short” polar IS1 insertions are all comprised of the same DNA with a duplex length of 750±80 nucleotide pairs. This insertable IS1 DNA can be integrated with either orientation into the genome at various positions in the lac and gal operons of E. coli; however, the inserted sequence is not permuted. The r14 polar insertion in gene cII of phage λ also consists of the same IS1 DNA (Hirsch et al., 1972 b). “Long” insertions (1170 to 1490 nucleotide pairs) were detected in the lac (IS3) and gal (IS2, IS4) operons and in the y and P-Q regions (IS2) of the λ genome and measured as single-strand loops in the l/r heteroduplex DNA. The insertions in the latter two positions are homologous, although those found in the P-Q region do not exhibit any obvious polarity.read more
Citations
More filters
Journal ArticleDOI
Positive selection procedure for entrapment of insertion sequence elements in gram-negative bacteria.
TL;DR: The broad-host-range plasmid pUCD800 containing the sacB gene of Bacillus subtilis for use in the positive selection and isolation of insertion sequence (IS) elements in gram-negative bacteria was constructed in this article.
Journal ArticleDOI
Use of a conditionally lethal gene in Anabaena sp. strain PCC 7120 to select for double recombinants and to entrap insertion sequences.
TL;DR: Use of the sacB gene provides a simple, effective, positive selection for double recombinants in Anabaena sp.
Journal ArticleDOI
Insights on antibiotic resistance of Staphylococcus aureus from its whole genome: genomic island SCC
TL;DR: Completion of whole genome sequences of three methicillin-resistant S. aureus (MRSA) strains has provided a bird's-eye view of the distribution of the mobile genetic elements in the bacterial chromosome that encode antibiotic resistance as well as pathogenicity in S.aureus.
Journal ArticleDOI
Mobile genetic elements of Staphylococcus aureus
Natalia Malachowa,Frank R. DeLeo +1 more
TL;DR: Understanding of S. aureus MGEs and the molecules they encode has played an important role toward these ends and has provided detailed insight into the evolution of antimicrobial resistance mechanisms and virulence.
Journal ArticleDOI
Prophage lambda at unusual chromosomal locations: I. Location of the secondary attachment sites and the properties of the lysogens
TL;DR: The integration, frequency of phage λ into a mutant host deleted for the normal prophage insertion site is reduced about 200-fold relative to integration into wild-type Escherichia coli.
References
More filters
Journal ArticleDOI
O0 and strong-polar mutations in the gal operon are insertions.
TL;DR: Three λ dg phages carrying strong-polar mutations in the gal operon are denser than the corresponding phage carrying the wildtype gal operons or reversions of the mutations to the Gal+ phenotype.
Journal ArticleDOI
Mutations caused by the insertion of genetic material into the galactose operon of Escherichia coli.
TL;DR: Density-gradient analysis shows that λ transducing phages which carry spontaneous extreme polar mutations of the galactose operon have higher buoyant densities than otherwise identical phage which carry a wild-type galactoses operon.
Journal ArticleDOI
Electron Micrographic Mapping of Deletions, Insertions, Inversions, and Homologies in the DNAs of Coliphages Lambda and Phi 80
TL;DR: The study of the functional organization of the DNA molecules of several bacteriophages has been the primary concern of this laboratory during the past few years, and has led to a novel technique, designated electron micrographic mapping of heteroduplex DNA (Westmoreland et al., 1969).
Journal ArticleDOI
Electron microscopy of polar insertions in the lac operon of Escherichia coli
TL;DR: Four insertion sites in the omega region of gene z were identified and the position of the lac5 substitution and the SR2 deletion in the λplac DNA were determined by heteroduplex mapping.
Journal ArticleDOI
Two kinds of insertions in bacterial genes.
Heinz-Josef Hirsch,Heinz-Josef Hirsch,Peter Starlinger,Peter Starlinger,Philippe Brachet,Philippe Brachet +5 more
TL;DR: These data are supported by cross-hybridization experiments using RNA transcribed in vitro from lambda dgal or lambda DNA carrying one insertion and DNA carrying either the same or a different insertion.