Human cytomegalovirus: taking the strain
MetadataDangos cofnod eitem llawn
In celebrating the 60th anniversary of the first isolation of human cytomegalovirus (HCMV), we reflect on the merits and limitations of the viral strains currently being used to develop urgently needed treatments. HCMV research has been dependent for decades on the high-passage strains AD169 and Towne, heavily exploiting their capacity to replicate efficiently in fibroblasts. However, the genetic integrity of these strains is so severely compromised that great caution needs to be exercised when considering their past and future use. It is now evident that wild-type HCMV strains are not readily propagated in vitro. HCMV mutants are rapidly selected during isolation in fibroblasts, reproducibly affecting gene RL13, the UL128 locus (which includes genes UL128, UL130 and UL131A) and often the UL/b′ region. As a result, the virus becomes less cell associated, altered in tropism and less pathogenic. This problem is not restricted to high-passage strains, as even low-passage strains can harbour biologically significant mutations. Cloning and manipulation of the HCMV genome as a bacterial artificial chromosome (BAC) offers a means of working with stable, genetically defined strains. To this end, the low-passage strain Merlin genome was cloned as a BAC and sequentially repaired to match the viral sequence in the original clinical sample from which Merlin was derived. Restoration of UL128L to wild type was detrimental to growth in fibroblasts, whereas restoration of RL13 impaired growth in all cell types tested. Stable propagation of phenotypically wild-type virus could be achieved only by placing both regions under conditional expression. In addition to the development of these tools, the Merlin transcriptome and proteome have been characterized in unparalleled detail. Although Merlin may be representative of the clinical agent, high-throughput whole-genome deep sequencing studies have highlighted the remarkable high level of interstrain variation present in circulating virus. There is a need to develop systems capable of addressing the significance of this diversity, free from the confounding effects of genetic changes associated with in vitro adaptation. The generation of a set of BAC clones, each containing the genome of a different HCMV strain repaired to match the sequence in the clinical sample, would provide a pathway to address the biological and clinical effects of natural variation in wild-type HCMV.
Medical Microbiology and Immunology;
Wilkinson, G.W., Davison, A.J., Tomasec, P., Fielding, C.A., Aicheler, R., Murrell, I., Seirafian, S., Wang, E.C., Weekes, M., Lehner, P.J., Wilkie, G.S., Stanton, R.J. (2015) 'Human cytomegalovirus: taking the strain', Medical Microbiology and Immunology, 204(3), pp.273-284.
Dynodwr Gwrthrych Digidol (DOI)https://doi.org/10.1007/s00430-015-0411-4
This article was published open access in Medical Microbiology and Immunology on 17 April 2015 (online), available at https://doi.org/10.1007/s00430-015-0411-4
Yn dangos eitemau sy’n perthyn drwy deitl, awdur, pwnc a chrynodeb.
Comparative Genomics and Pan-Genomics of the Myxococcaceae, including a Description of Five Novel Species: Myxococcus eversor sp. nov., Myxococcus llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogochensis sp. nov., Myxococcus vastator sp. nov., Pyxidicoccus caerfyrddinensis sp. nov., and Pyxidicoccus trucidator sp. nov. Chambers, James; Sparks, Natalie; Sydney, Natashia; Livingstone, Paul; Cookson, Alan; Whitworth, David (Oxford Academic, 2020-10-06)Members of the predatory Myxococcales (myxobacteria) possess large genomes, undergo multicellular development, and produce diverse secondary metabolites, which are being actively prospected for novel drug discovery. To ...
Genome sequencing and pan-genome analysis of 23 Corallococcus spp. strains reveal unexpected diversity, with particular plasticity of predatory gene sets Livingstone, Paul; Morphew, Russell; Whitworth, David (Frontiers Media, 2018-12-19)Corallococcus is an abundant genus of predatory soil myxobacteria, containing two species, C. coralloides (for which a genome sequence is available) and C. exiguus. To investigate the genomic basis of predation, we ...
Zwarycz, Allison; Livingstone, Paul; Whitworth, David (Royal Society of Chemistry, 2020-04-29)Extracellular membrane vesicles are produced by all domains of life (bacteria, archaea and eukaryotes). Bacterial extracellular vesicles (outer membrane vesicles or OMVs) are produced by outer membrane blebbing, and contain ...