TY - JOUR
T1 - Nonintegrated plasmid-folded chromosome complexes. Genetic studies on formation and possible relationship to plasmid replication
AU - Miller, J.
AU - Manis, J.
AU - Kline, B.
AU - Bishop, A.
N1 - Funding Information:
This research was supported in part by the Mayo Foundation and by Public Health Service Research Grant GM22682a wardedto B. Kline by the National Instituteso f General Medical Sciences. We also thank David Allison for his expert assistance in electron microscopy. A portion of this work was submittedb y J. Miller to the University of Tennessee (Knoxville) Graduate School in partial fulfillment of the requirements for a Doctor of Philosophy Degree in Biochemistry.
PY - 1978/6
Y1 - 1978/6
N2 - When folded chromosomes are purified from plasmid-containing bacteria, a reproducible fraction of the host's covalently closed, circular (CCC) plasmid DNA copurifies with the chromosomes. From this copurification, we infer the existence of nonintegrative plasmid-chromosome (NPC) complexes. Previously, we noted that plasmids dependent on DNA polymerase III and with stringent control of replication complex to a greater extent than plasmids dependent on DNA polymerase I and with relaxed control of replication. We have examined this subject in more depth and find that: (i) The composite plasmids formed by in vitro recombination of a "stringent" with a "relaxed" replicon complex to chromosomes at the frequency of the component replicon which directs replication; (ii) all of the detectable replicative intermediates, but only 25% of the CCC forms, of plasmid ColE1 complex to chromosome; and (iii) when a mini-F plasmid is deleted for the DNA sequences which include the primary origin of replication, the complexing frequency decreases 30 to 40%. We conclude from these findings that NPC complexes either indirectly or directly relate to plasmid replication. Further, we find that the EcoRI kan+ fragments of pML31 and the ampicillin resistance transposon, Tn3, promote complexing of both ColE1 and mini-F plasmids to host chromosomes. The biological significance of this latter complexing is unknown. However, we conclude from these studies and from point (iii) that complexing is determined in part by unique plasmid sequences.
AB - When folded chromosomes are purified from plasmid-containing bacteria, a reproducible fraction of the host's covalently closed, circular (CCC) plasmid DNA copurifies with the chromosomes. From this copurification, we infer the existence of nonintegrative plasmid-chromosome (NPC) complexes. Previously, we noted that plasmids dependent on DNA polymerase III and with stringent control of replication complex to a greater extent than plasmids dependent on DNA polymerase I and with relaxed control of replication. We have examined this subject in more depth and find that: (i) The composite plasmids formed by in vitro recombination of a "stringent" with a "relaxed" replicon complex to chromosomes at the frequency of the component replicon which directs replication; (ii) all of the detectable replicative intermediates, but only 25% of the CCC forms, of plasmid ColE1 complex to chromosome; and (iii) when a mini-F plasmid is deleted for the DNA sequences which include the primary origin of replication, the complexing frequency decreases 30 to 40%. We conclude from these findings that NPC complexes either indirectly or directly relate to plasmid replication. Further, we find that the EcoRI kan+ fragments of pML31 and the ampicillin resistance transposon, Tn3, promote complexing of both ColE1 and mini-F plasmids to host chromosomes. The biological significance of this latter complexing is unknown. However, we conclude from these studies and from point (iii) that complexing is determined in part by unique plasmid sequences.
UR - http://www.scopus.com/inward/record.url?scp=0017981912&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0017981912&partnerID=8YFLogxK
U2 - 10.1016/0147-619X(78)90045-8
DO - 10.1016/0147-619X(78)90045-8
M3 - Article
C2 - 372965
AN - SCOPUS:0017981912
SN - 0147-619X
VL - 1
SP - 273
EP - 283
JO - Plasmid
JF - Plasmid
IS - 3
ER -