A comparison of AMPV subtypes A and B full genomes, gene transcripts and proteins led to reverse-genetics systems rescuing both subtypes

Abstract

Avian metapneumovirus (AMPV) infection of poultry causes serious disease in most countries and subtype A reverse-genetic (RG) systems have allowed a generation of viruses of known sequence, and proved useful in developments towards better control by live vaccines. While subtype B viruses are more prevalent, bacterial cloning issues made subtype B RG systems difficult to establish. A molecular comparison of subtype A and B viruses was undertaken to assess whether subtype A RG components could be partially or fully substituted. AMPV subtype A and B gene-end sequences leading to polyadenylation are, to our knowledge, reported for the first time, as well as several leader and trailer sequences. After comparing these alongside previously reported gene starts and protein sequences, it was concluded that subtype B genome copies would be most likely rescued by a subtype A support system, and this assertion was supported when individual subtype A components were successfully substituted. Application of an advanced cloning plasmid permitted eventual completion of a fully subtype B RG system, and proved that all subtype-specific components could be freely exchanged between A and B systems.

What is new on molecular characteristics of Avian metapneumovirus strains circulating in Europe?

“…Promising reverse genetics systems for aMPV have been developed in recent years for A, B and C subtypes (Laconi et al., 2016; Naylor et al., 2004; Yu, Estevez, Song, Kapczynski, & Zsak, 2010), other than being an exceptional tool for the study of the virus properties (Brown et al., 2011), and can be used for the development of rationally modified aMPV vaccines (Naylor, Lupini, & Brown, 2010) or recombinant vaccines (Falchieri et al., 2013) expressing foreign genes.…”

Molecular characterization of whole genome sequence of infectious bronchitis virus 624I genotype confirms the close relationship with Q1 genotype

“…3′ end of the genome was determined using a 3′RACE protocol previously described (Laconi et al, 2016). Briefly, RT was performed with a primer containing 20 Ts followed by an adaptor sequence at its 5′ terminus.…”