High-fidelity long-read sequencing of an avian herpesvirus reveals extensive intrapopulation diversity in tandem repeat regions
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Open Access
- 25 August 2025
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS Pathogens
- Vol. 21 (8) , e1013435
Abstract
Comparative genomic studies of Marek’s disease virus (MDV) have suggested that attenuated and virulent strains share >98% sequence identity. However, these estimates fail to account for variation in regions of the MDV genome harboring tandem repeats. To resolve these loci and enable assessments of intrapopulation diversity, we used a PacBio Sequel II platform to sequence MDV strains CVI988/Rispens (attenuated), HPRS-B14 (virulent), Md5 (very virulent) and 675A (very virulent plus). This approach enabled us to identify patterns of variation in tandem repeat regions that may contribute to the known phenotypic differences between these strains, including the proline-rich regions of the meq oncogene (Meq-PRR) and MDV049/UL36 (UL36-PRR), the multiple telomeric repeats (mTMR) region of the a-like sequence, the promoter region of the latency-associated transcript (LAT), and the MDV006.5/MDV075.2 transcripts. We also found CVI988/Rispens variants showing a 4.3-kb deletion in the Unique Short (US) region, resulting in the loss of SORF1, SORF2, US1, US10, SORF3, and US2. Despite the conventional wisdom that MDV harbors little genomic diversity even when compared to other herpesviruses, we found MDV tandem repeat regions to be highly variable both within individual samples and across strains. In addition to providing a foundation for future studies seeking to explore a potential link between MDV tandem repeats and phenotypic traits like virulence and attenuation, these findings provide detailed support for the premise that DNA viruses can harbor high levels of within-sample diversity in tandem repeat regions.Keywords
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Funding Information
- National Institute of General Medical Sciences (R01 GM140459)
- Biotechnology and Biological Sciences Research Council (BBS/E/I/00007038)
- Biotechnology and Biological Sciences Research Council (BBS/E/PI/23NB0003)
- Biotechnology and Biological Sciences Research Council (BB/V017748/1)
- National Institute of General Medical Sciences (R01 GM140459)
- Biotechnology and Biological Sciences Research Council (BBS/E/I/00007038)
- Biotechnology and Biological Sciences Research Council (BBS/E/PI/23NB0003)
- Biotechnology and Biological Sciences Research Council (BB/V017748/1)
This publication has 124 references indexed in Scilit:
- PacBio Sequencing and its ApplicationsGenomics, Proteomics & Bioinformatics, 2015
- Vaccine and oncogenic strains of gallid herpesvirus 2 contain specific subtype variations in the 5′ region of the latency-associated transcript that evolve in vitro and in vivoArchives of Virology, 2014
- Sequence determination of variable regions within the genomes of gallid herpesvirus-2 pathotypesArchives of Virology, 2007
- Oncogenic Marek’s disease viruses lacking the 132 base pair repeats can still be attenuated by serial in vitro cell culture passagesVirus Genes, 2007
- Polymorphisms in the repeat long regions of oncogenic and attenuated pathotypes of Marek’s disease virus 1Virus Genes, 2006
- Stability of Marek’s disease virus 132-bp repeats during serial in vitro passagesArchives of Virology, 2006
- PCR detection of amplified 132 bp repeats in Marek's disease virus type 1 (MDV-1) DNA can serve as an indicator for critical genomic rearrangement leading to the attenuation of virus virulenceVirus Genes, 1993
- Wide occurrence of measles virus subgenomic RNAs in attenuated live-virus vaccinesBiologicals, 1990
- Reiterated sequences of herpes simplex virus type 1 (HSV-1) genome can serve as physical markers for the differentiation of HSV-1 strainsArchives of Virology, 1989
- Defective interfering particles from poliovirus vaccine and vaccine reference strainsVirology, 1974