title: Investigation of the unstable attenuation exhibited by a chicken anaemia virus isolate.
abstract: An attenuated chicken anaemia virus (CAV) isolate, cloned isolate 10, which was molecularly cloned from the Cuxhaven-1 CAV after 173 cell-culture passages, was shown previously to recover pathogenicity following 10 passages in young chicks. The consensus nucleotide sequence of the 'revertant' (Rev) virus, present as a tissue homogenate, differed from cloned isolate 10 at a single nucleotide residue (nucleotide 1739) that changed amino acid 287 of the capsid protein from alanine to aspartic acid. Subjecting Rev virus to 10 cell-culture passages reselected viruses with an alanine at this amino acid position. Experimental infections using a molecularly cloned Rev virus isolate demonstrated that the mutation at nucleotide 1739 was not in itself responsible for the recovery of pathogenicity exhibited by the Rev virus. Additional sequence analyses of cloned amplicons provided evidence that the Rev virus population comprised minor, genetically different subpopulations, and provided an indication of CAV's potential for genetic change.
authors.affiliation: Department of Agriculture and Rural Development for Northern Ireland, Veterinary Sciences Division, Stormont, Belfast BT4 3SD, UK. Daniel.Todd@dardni.gov.uk
authors.forename: Daniel
authors.initials: D
authors.lastname: Todd
authors.forename: Julie L
authors.initials: JL
authors.lastname: Creelan
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Connor
authors.forename: Neris W
authors.initials: NW
authors.lastname: Ball
authors.forename: Alistair N J
authors.initials: AN
authors.lastname: Scott
authors.forename: Brian M
authors.initials: BM
authors.lastname: Meehan
authors.forename: Gerard F
authors.initials: GF
authors.lastname: McKenna
authors.forename: M S
authors.initials: MS
authors.lastname: McNulty
mesh_terms: D000818:Animals; D017727:Chicken anemia virus / Q000302:isolation & purification / Q000472:pathogenicity*; D002645:Chickens / Q000821:virology*; D018173:Circoviridae Infections / Q000662:veterinary* / Q000821:virology; D015967:Gene Expression Regulation, Viral; D011201:Poultry Diseases / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D014764:Viral Proteins