A gene associated with cell division and drug resistance in Giardia duodenalis.
A 3000 bp cDNA insert (G6/1) from Giardia duodenalis, cloned into Escherichia coli is located on chromosome 3 of Giardia stocks which have 3 chromosomes detectable by field-inversion gel electrophoresis in the range 650-800 kb and on chromosome 3 and/or 4 of stocks with 4 chromosomes in this size range. The loss of this sequence from chromosome 4 but not chromosome 3 was associated with the induction of drug resistance in a previously sensitive laboratory stock. G6/1 appears to represent a single copy gene in Giardia as determined by hybridization of the probe to cleaved genomic DNA. Furthermore, the sequences flanking at least 12 kb of G6/1 are the same when G6/1 appears on both chromosomes 3 and 4. The cDNA encodes a protein associated with the nuclei of trophozoites during some stages of growth of the parasite. In a non-dividing culture, the antigen is associated with the nuclei of about 30% of trophozoites and fewer in a dividing culture. Three Giardia stocks with obvious chromosome rearrangements, which grow poorly and fail to divide normally, apparently lack the DNA sequence G6/1.
Upcroft
J A
JA
Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia.
Healey
A
A
Murray
D G
DG
Boreham
P F
PF
Upcroft
P
P
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D015139:Blotting, Southern; D002455:Cell Division / Q000235:genetics; D002467:Cell Nucleus / Q000276:immunology; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000032:analysis; D004351:Drug Resistance / Q000235:genetics; D005455:Fluorescent Antibody Technique; D005872:Giardia / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D008795:Metronidazole / Q000494:pharmacology*; D051379:Mice; D009693:Nucleic Acid Hybridization; D015800:Protozoan Proteins / Q000032:analysis / Q000276:immunology; D015183:Restriction Mapping
D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D007106:Immune Sera; D015800:Protozoan Proteins; D008795:Metronidazole