Open AccessAn immune strain of Halobacterium halobium carries the invertible L segment of phage ΦH as a plasmid
Author(s) -
Heinke Schnabel
Publication year - 1984
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.81.4.1017
Subject(s) - lysogen , prophage , plasmid , biology , lysogenic cycle , reversion , inverted repeat , strain (injury) , temperateness , genetics , bacteriophage , dna , microbiology and biotechnology , virology , genome , gene , escherichia coli , phenotype , anatomy
The structure of the circular prophage genome of ΦH varies with high frequency in single colony progeny of the defective lysogenHalobacterium halobium R1 -3. As in linear ΦH DNA, a segment flanked by two copies of the insertion element ISH1.8 is inverted frequently. This L segment can also circularize to a plasmid of 12 kilobase pairs with simultaneous loss of the remaining phage DNA. Strain R1 -L, which contains this plasmid, is immune to phage infection. A phage variant, ΦHL1, is able to grow on R1 -L and carries an insertion of 1 kilobase pair in its L segment. ΦHL1 does not grow on normal lysogens. This shows that the plasmid confers to R1 -L only part of the immunity of normal lysogens.