Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Repair of an attenuated low-passage murine cytomegalovirus bacterial artificial chromosome identifies a novel spliced gene essential for salivary gland tropism

Redwood, A.J., Masters, L.L., Chan, B., Leary, S., Forbes, C., Jonjic, S., Juranić Lisnić, V., Lisnić, B., Smith, L.M. and Jung, J.U. (2020) Repair of an attenuated low-passage murine cytomegalovirus bacterial artificial chromosome identifies a novel spliced gene essential for salivary gland tropism. Journal of Virology, 94 (22). Art. e01456-20.

Link to Published Version: https://doi.org/10.1128/JVI.01456-20
*Subscription may be required

Abstract

The cloning of herpesviruses as bacterial artificial chromosomes (BACs) has revolutionized the study of herpesvirus biology, allowing rapid and precise manipulation of viral genomes. Several clinical strains of human cytomegalovirus (HCMV) have been cloned as BACs; however, no low-passage strains of murine CMV (MCMV), which provide a model mimicking these isolates, have been cloned. Here, the low-passage G4 strain of was BAC cloned. G4 carries an m157 gene that does not ligate the natural killer (NK) cell-activating receptor, Ly49H, meaning that unlike laboratory strains of MCMV, this virus replicates well in C57BL/6 mice. This BAC clone exhibited normal replication during acute infection in the spleen and liver but was attenuated for salivary gland tropism. Next-generation sequencing revealed a C-to-A mutation at nucleotide position 188422, located in the 3′ untranslated region of sgg1, a spliced gene critical for salivary gland tropism. Repair of this mutation restored tropism for the salivary glands. Transcriptional analysis revealed a novel spliced gene within the sgg1 locus. This small open reading frame (ORF), sgg1.1, starts at the 3′ end of the first exon of sgg1 and extends exon 2 of sgg1. This shorter spliced gene is prematurely terminated by the nonsense mutation at nt 188422. Sequence analysis of tissue culture-passaged virus demonstrated that sgg1.1 was stable, although other mutational hot spots were identified. The G4 BAC will allow in vivo studies in a broader range of mice, avoiding the strong NK cell responses seen in B6 mice with other MCMV BAC-derived MCMVs.

Item Type: Journal Article
Murdoch Affiliation: Institute for Immunology and Infectious Diseases
Publisher: American Society for Microbiology
Copyright: © 2020 American Society for Microbiology
URI: http://researchrepository.murdoch.edu.au/id/eprint/58552
Item Control Page Item Control Page