Abstract
The immunity region from a cI857 derivative of bacteriophage λ has been cloned into the EcoRI site of pBR322 to produce a plasmid that can be used to analyze spontaneous mutagenesis. Cells containing this plasmid are temperature-sensitive for growth unless mutations have occurred that somehow prevent the expression of the kil gene in the λ fragment at non-permissive temperature. 678 such temperature-resistant mutants from 10 independent subcultures each of 2 different recA- E. coli strains have been collected, and the nature of the plasmid mutations obtained has been analyzed. All of the subcultures contained mutants that allowed growth at the restrictive without showing a detectable change in plasmid size. 75% of the total mutants fell in this class. More than half of these mutations involved the λ leftward promoter, pL, and such mutants were found in all 20 subcultures. The remaining 25% of the mutations involved a change in plasmid size and mutations of this class were found in 18 of 20 subcultures. 12% of the total mutants (found in 16 of 20 subcultures) had an insertion of IS1 in the region between pL and the λkil gene. 6% of the total mutants had undergone an IS1-mediated deletion, while 1% were mixed colonies in which multiple IS1-mediated events had occurred. About 1% of the total mutants had undergone complex IS1-mediated DNA rearrangement(s) that have not yet been characterized. In total, 11 of 20 subcultures yielded isolates where IS1-mediated rearrangements had occurred. The remaining 4% of the mutations included insertions of IS5, IS30, and an IS1 family member that appears to be IS1T as well as IS1T-mediated deletions and deletions that do not appear to have been mediated by any insertion sequence. A mutant with both an IS1 insetion and an alteration involving pL has also been isolated.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 23-37 |
| Number of pages | 15 |
| Journal | Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis |
| Volume | 197 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 1988 |
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All Science Journal Classification (ASJC) codes
- Molecular Biology
- Health, Toxicology and Mutagenesis
- Medicine(all)
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Characterization of the types of mutational events that spontaneously occur in a plasmid system. / Chen, Jiann Hwa; Porter, Ronald D.
In: Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, Vol. 197, No. 1, 01.01.1988, p. 23-37.Research output: Contribution to journal › Article
TY - JOUR
T1 - Characterization of the types of mutational events that spontaneously occur in a plasmid system
AU - Chen, Jiann Hwa
AU - Porter, Ronald D.
PY - 1988/1/1
Y1 - 1988/1/1
N2 - The immunity region from a cI857 derivative of bacteriophage λ has been cloned into the EcoRI site of pBR322 to produce a plasmid that can be used to analyze spontaneous mutagenesis. Cells containing this plasmid are temperature-sensitive for growth unless mutations have occurred that somehow prevent the expression of the kil gene in the λ fragment at non-permissive temperature. 678 such temperature-resistant mutants from 10 independent subcultures each of 2 different recA- E. coli strains have been collected, and the nature of the plasmid mutations obtained has been analyzed. All of the subcultures contained mutants that allowed growth at the restrictive without showing a detectable change in plasmid size. 75% of the total mutants fell in this class. More than half of these mutations involved the λ leftward promoter, pL, and such mutants were found in all 20 subcultures. The remaining 25% of the mutations involved a change in plasmid size and mutations of this class were found in 18 of 20 subcultures. 12% of the total mutants (found in 16 of 20 subcultures) had an insertion of IS1 in the region between pL and the λkil gene. 6% of the total mutants had undergone an IS1-mediated deletion, while 1% were mixed colonies in which multiple IS1-mediated events had occurred. About 1% of the total mutants had undergone complex IS1-mediated DNA rearrangement(s) that have not yet been characterized. In total, 11 of 20 subcultures yielded isolates where IS1-mediated rearrangements had occurred. The remaining 4% of the mutations included insertions of IS5, IS30, and an IS1 family member that appears to be IS1T as well as IS1T-mediated deletions and deletions that do not appear to have been mediated by any insertion sequence. A mutant with both an IS1 insetion and an alteration involving pL has also been isolated.
AB - The immunity region from a cI857 derivative of bacteriophage λ has been cloned into the EcoRI site of pBR322 to produce a plasmid that can be used to analyze spontaneous mutagenesis. Cells containing this plasmid are temperature-sensitive for growth unless mutations have occurred that somehow prevent the expression of the kil gene in the λ fragment at non-permissive temperature. 678 such temperature-resistant mutants from 10 independent subcultures each of 2 different recA- E. coli strains have been collected, and the nature of the plasmid mutations obtained has been analyzed. All of the subcultures contained mutants that allowed growth at the restrictive without showing a detectable change in plasmid size. 75% of the total mutants fell in this class. More than half of these mutations involved the λ leftward promoter, pL, and such mutants were found in all 20 subcultures. The remaining 25% of the mutations involved a change in plasmid size and mutations of this class were found in 18 of 20 subcultures. 12% of the total mutants (found in 16 of 20 subcultures) had an insertion of IS1 in the region between pL and the λkil gene. 6% of the total mutants had undergone an IS1-mediated deletion, while 1% were mixed colonies in which multiple IS1-mediated events had occurred. About 1% of the total mutants had undergone complex IS1-mediated DNA rearrangement(s) that have not yet been characterized. In total, 11 of 20 subcultures yielded isolates where IS1-mediated rearrangements had occurred. The remaining 4% of the mutations included insertions of IS5, IS30, and an IS1 family member that appears to be IS1T as well as IS1T-mediated deletions and deletions that do not appear to have been mediated by any insertion sequence. A mutant with both an IS1 insetion and an alteration involving pL has also been isolated.
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U2 - 10.1016/0027-5107(88)90137-6
DO - 10.1016/0027-5107(88)90137-6
M3 - Article
C2 - 2827020
AN - SCOPUS:0023801155
VL - 197
SP - 23
EP - 37
JO - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
JF - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
SN - 1386-1964
IS - 1
ER -