Sequential Autoprocessing of Marek's Disease Herpesvirus Protease Differs from That of Other Herpesviruses

Abstract

Herpesviruses encode a unique serine protease essential for viral capsid maturation. This protease undergoes autoprocessing at two sites, R and M, at the consensus sequence (V, L, I) P3 -X P2 -A P1 /S P1 (where X is a polar amino acid). We observed complete autoprocessing at the R and M sites of Marek's disease virus (MDV) protease following production of the polyprotein in Escherichia coli. Site-directed mutagenesis confirmed the predicted sequence of the R and M sites, with the M site sequence being nonconsensual: M P3 -N P2 -A P1 /S P1 . Mutagenesis and expression kinetics studies suggested that the atypical MDV M site was cleaved exclusively by the processed short protease, a feature making MDV unique among herpesviruses.

Expression of immunogenic structural proteins of cyprinid herpesvirus 3 in vitro assessed using immunofluorescence

“…Fuchs et al [ 16 ] observed similar molecular weight multiple banding on immunoblots screened with rabbit anti-sera raised to CyHV-3 ORF149—the target antigen of MAb 10A9. In herpesviruses, protease precursors undergo auto-processing and cleavage in order to achieve cleavage of subsequent polyproteins during capsid maturation and shell assembly [ 44 ], which can also lead to multiple bands being recognised by individual MAbs [ 45 ]. Alternatively, MAbs detecting glycoproteins may also recognise the antigen at multiple molecular weights due to a larger molecule being synthesised following glycosylation and other post-translational modifications resulting in the addition of oligosaccharides, and/or glycosylation intermediates [ 46 , 47 ].…”

Prevalence and molecular characterization of meq in feather follicular epithelial cells of Korean broiler chickens

“…Among them three were located in the basic region containing the major nuclear localization (NLS) and nucleolar functions (NoLs) and they were thought to affect NLS or NoLs function [15]. The SNPs in the present study could not be compared directly with the previous study because they were present at codons 176, 179, 217, and 266.…”

“…On the basis of the four SNPs Korean Meq genes were separated into four alleles-I, II, III, and IV. Although the sample numbers were insufficient, allele II was the prevalent allele, followed by allele I. Alleles III and IV were observed in only one sample each, and the frequencies of each allele should be distinguished from a specific mutation of an individual virus by further studies [15]. 0301-131 and 0301-266 which were originated from 3-week-old chickens in unvaccinated farms were grouped into allele I but others which were from 5-week-old chickens in unvaccinated farms were grouped into other alleles.…”

“…A study on SNPs of meq was already conducted and six alleles were defined according to the five SNPs identified from 71 to 122 codons [15]. Among them three were located in the basic region containing the major nuclear localization (NLS) and nucleolar functions (NoLs) and they were thought to affect NLS or NoLs function [15].…”

“…L-Meq forms a heterodimer with Meq and suppresses the replication of MDV1, but the functions of S-Meq and VS-Meq have yet to be fully elucidated [14]. A single nucleotide polymorphism (SNP) study has been conducted with MDV, and distinct alleles have been delineated [15]. The study proved to be useful in the classification of MDV into subgroups, and also augmented current understanding of the epizootiology of MD.…”