PMID- 11160894
OWN - NLM
STAT- MEDLINE
DCOM- 20010503
LR  - 20190501
IS  - 1362-4962 (Electronic)
IS  - 0305-1048 (Print)
IS  - 0305-1048 (Linking)
VI  - 29
IP  - 3
DP  - 2001 Feb 1
TI  - An alteration in concatameric structure is associated with efficient segregation 
      of plasmids in transfected Plasmodium falciparum parasites.
PG  - 716-24
AB  - Transfection of the human malaria parasite Plasmodium falciparum is currently 
      performed with circularised plasmids that are maintained episomally in parasites 
      under drug selection but which are rapidly lost when selection pressure is 
      removed. In this paper, we show that in instances where gene targeting is not 
      favoured, transfected plasmids can change to stably replicating forms (SRFs) that 
      are maintained episomally in the absence of drug selection. SRF DNA is a large 
      concatamer of the parental plasmid comprising at least nine plasmids arranged in 
      a head-to-tail array. We show as well that the original unstable replicating 
      forms (URFs) are also present as head-to-tail concatamers, but only comprise 
      three plasmids. Limited digestion and gamma irradiation experiments revealed that 
      while URF concatamers are primarily circular, as expected, SRF concatamers form a 
      more complex structure that includes extensive single-stranded DNA. No evidence 
      of sequence rearrangement or additional sequence was detected in SRF DNA, 
      including in transient replication experiments designed to select for more 
      efficiently replicating plasmids. Surprisingly, these experiments revealed that 
      the bacterial plasmid alone can replicate in parasites. Together, these results 
      imply that transfected plasmids are required to form head-to-tail concatamers to 
      be maintained in parasites and implicate both rolling-circle and 
      recombination-dependent mechanisms in their replication.
FAU - O'Donnell, R A
AU  - O'Donnell RA
AD  - Department of Microbiology and Immunology and the CRC for Vaccine Technology, The 
      University of Melbourne, VIC 3010, Australia.
FAU - Preiser, P R
AU  - Preiser PR
FAU - Williamson, D H
AU  - Williamson DH
FAU - Moore, P W
AU  - Moore PW
FAU - Cowman, A F
AU  - Cowman AF
FAU - Crabb, B S
AU  - Crabb BS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Nucleic Acids Res
JT  - Nucleic acids research
JID - 0411011
RN  - 0 (Antiprotozoal Agents)
RN  - 0 (DNA, Protozoan)
RN  - Z3614QOX8W (Pyrimethamine)
SB  - IM
MH  - Animals
MH  - Antiprotozoal Agents/pharmacology
MH  - Blotting, Southern
MH  - DNA, Protozoan/genetics
MH  - Drug Resistance, Microbial
MH  - Electrophoresis, Gel, Pulsed-Field
MH  - Plasmids/*genetics
MH  - Plasmodium falciparum/drug effects/*genetics
MH  - Pyrimethamine/pharmacology
MH  - Transfection
PMC - PMC30406
EDAT- 2001/02/13 11:00
MHDA- 2001/05/22 10:01
PMCR- 2001/02/01
CRDT- 2001/02/13 11:00
PHST- 2001/02/13 11:00 [pubmed]
PHST- 2001/05/22 10:01 [medline]
PHST- 2001/02/13 11:00 [entrez]
PHST- 2001/02/01 00:00 [pmc-release]
AID - gke178 [pii]
AID - 10.1093/nar/29.3.716 [doi]
PST - ppublish
SO  - Nucleic Acids Res. 2001 Feb 1;29(3):716-24. doi: 10.1093/nar/29.3.716.