Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: DrugBank:EXPT01586 (
G418
)
2,237
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Messenger RNAs containing premature translation stop codons are degraded by a nonsense-mediated mRNA decay (NMD) system. The NMD pathway is present in yeast, plants and mammals and is thought to protect cells from production of nonfunctional proteins by rapidly degrading mutant mRNAs. There is little understanding of the biology of the origins of eukaryotes, particularly of the NMD pathway. Searches using the BLAST program revealed that the protozoan Giardialamblia has only some of the components of the NMD pathway. We developed a luciferase reporter system with a nonsense mutation to monitor NMD in Giardia. The nonsense mutation triggered a decrease in luciferase mRNA levels and stability, suggesting that the NMD phenomenon could be present in Giardia. We also found a significant reduction of the mRNA levels of another system containing Giardia its own cyst wall protein 3 gene with a nonsense mutation. However, the reduction levels observed in these two systems are lower than that in late-branching eukaryotes, suggesting that the NMD system in Giardia may be less functional. Interestingly, the effect of
G418
in promoting read-through of the nonsense mutation and inhibiting NMD in Giardia is similar to that in late-branching eukaryotes. We also characterised the giardial homologue of a conserved NMD factor,
UPF1
. Immunofluorescence assays revealed that giardial
UPF1
, like yeast
UPF1
, is expressed in the cytoplasm, but not in the nucleus. In addition, overexpression of
UPF1
resulted in a reduction of the levels of nonsense-containing transcripts and enhanced translation termination at a nonsense codon. These results suggest that Giardia may have an incomplete NMD pathway and giardial
UPF1
may be functionally conserved, involved in NMD and in preventing nonsense suppression.
...
PMID:Incomplete nonsense-mediated mRNA decay in Giardia lamblia. 1843 Apr 26
