Analysis of genetic mutations in the 7a7b open reading frame of coronavirus of cheetahs (Acinonyx jubatus).
OBJECTIVE
To analyze the 7a7b genes of the feline coronavirus (FCoV) of cheetahs, which are believed to play a role in virulence of this virus.


METHODS
Biologic samples collected during a 4-year period from 5 cheetahs at the same institution and at 1 time point from 4 cheetahs at different institutions.


METHODS
Samples were first screened for FCoV via a reverse transcription-PCR procedure involving primers that encompassed the 3'-untranslated region. Samples that yielded positive assay results were analyzed by use of primers that targeted the 7a7b open reading frames. The nucleotide sequences of the 7a7b amplification products were determined and analyzed.


RESULTS
In most isolates, substantial deletional mutations in the 7a gene were detected that would result in aberrant or no expression of the 7a product because of altered reading frames. Although the 7b gene was also found to contain mutations, these were primarily point mutations resulting in minor amino acid changes. The coronavirus associated with 1 cheetah with feline infectious peritonitis had intact 7a and 7b genes.


CONCLUSIONS
The data suggest that mutations arise readily in the 7a region and may remain stable in FCoV of cheetahs. In contrast, an intact 7b gene may be necessary for in vivo virus infection and replication. Persistent infection with FCoV in a cheetah population results in continued virus circulation and may lead to a quasispecies of virus variants.
Department of Comparative Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4543, USA.
Melissa A
MA
Kennedy
Emily
E
Moore
Rebecca P
RP
Wilkes
Scott B
SB
Citino
Stephen A
SA
Kania
D002612:Acinonyx / Q000821:virology*; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D017934:Coronavirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D009154:Mutation; D016366:Open Reading Frames; D010802:Phylogeny; D017354:Point Mutation; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
D012367:RNA, Viral; D014764:Viral Proteins