title: Sequential mutations associated with adaptation of human cytomegalovirus to growth in cell culture.
abstract: Mutations that occurred during adaptation of human cytomegalovirus to cell culture were monitored by isolating four strains from clinical samples, passaging them in various cell types and sequencing ten complete virus genomes from the final passages. Mutational dynamics were assessed by targeted sequencing of intermediate passages and the original clinical samples. Gene RL13 and the UL128 locus (UL128L, consisting of genes UL128, UL130 and UL131A) mutated in all strains. Mutations in RL13 occurred in fibroblast, epithelial and endothelial cells, whereas those in UL128L were limited to fibroblasts and detected later than those in RL13. In addition, a region containing genes UL145, UL144, UL142, UL141 and UL140 mutated in three strains. All strains exhibited numerous mutations in other regions of the genome, with a preponderance in parts of the inverted repeats. An investigation was carried out on the kinetic growth yields of viruses derived from selected passages that were predominantly non-mutated in RL13 and UL128L (RL13+UL128L+), or that were largely mutated in RL13 (RL13-UL128L+) or both RL13 and UL128L (RL13-UL128L-). RL13-UL128L- viruses produced greater yields of infectious progeny than RL13-UL128L+ viruses, and RL13-UL128L+ viruses produced greater yields than RL13+UL128L+ viruses. These results suggest strongly that RL13 and UL128L exert at least partially independent suppressive effects on growth in fibroblasts. As all isolates proved genetically unstable in all cell types tested, caution is advised in choosing and monitoring strains for experimental studies of vulnerable functions, particularly those involved in cell tropism, immune evasion or growth temperance.
authors.affiliation: MRC Virology Unit, Institute of Virology, University of Glasgow, Church Street, Glasgow G11 5JR, UK. d.dargan@mrcvu.gla.ac.uk
authors.forename: Derrick J
authors.initials: DJ
authors.lastname: Dargan
authors.forename: Elaine
authors.initials: E
authors.lastname: Douglas
authors.forename: Charles
authors.initials: C
authors.lastname: Cunningham
authors.forename: Fiona
authors.initials: F
authors.lastname: Jamieson
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Stanton
authors.forename: Katarina
authors.initials: K
authors.lastname: Baluchova
authors.forename: Brian P
authors.initials: BP
authors.lastname: McSharry
authors.forename: Peter
authors.initials: P
authors.lastname: Tomasec
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Emery
authors.forename: Elena
authors.initials: E
authors.lastname: Percivalle
authors.forename: Antonella
authors.initials: A
authors.lastname: Sarasini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gerna
authors.forename: Gavin W G
authors.initials: GW
authors.lastname: Wilkinson
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Davison
mesh_terms: D000220:Adaptation, Biological; D002460:Cell Line; D003587:Cytomegalovirus / Q000235:genetics* / Q000254:growth & development* / Q000302:isolation & purification; D003586:Cytomegalovirus Infections / Q000821:virology; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D042783:Endothelial Cells / Q000821:virology; D004847:Epithelial Cells / Q000821:virology; D005347:Fibroblasts / Q000821:virology; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D014764:Viral Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins