Molecular characterization of Lelystad virus.
Lelystad virus (LV), the prototype of porcine reproductive respiratory syndrome virus, is a small enveloped virus, containing a positive strand RNA genome of 15 kb. LV is tentatively classified in the family Arteriviridae, which consists of lactate dehydrogenase-elevating virus (LDV), equine arteritis virus (EAV) and simian hemorrhagic fever virus (SHFV). These viruses have a similar genome organization and replication strategy as coronaviruses, but the size of the genome is much smaller (12-15 kb) and they have different morphological and physicochemical properties. The genome of LV contains eight open reading frames (ORFs) that encode the replicase genes (ORFs 1a and 1b), envelope proteins (ORFs 2 to 6) and the nucleocapsid protein (ORF7). Genomic comparison of European and North American isolates has shown that the structural proteins encoded by ORFs 2 to 7 vary widely. The amino acid sequences of ORFs 2 to 7 of North American strains share only 55 to 79% identical amino acids with those of European strains. Using polyvalent porcine anti-LV serum, gene-specific anti-peptide sera and monoclonal antibodies, we have identified six structural proteins of LV and their corresponding genes. These are: the 15 kDa unglycosylated nucleocapsid protein (N) encoded by ORF7, an 18 kDa unglycosylated integral membrane protein M encoded by ORF6, a 25 kDa N-glycosylated protein encoded by ORF5, a 31-35 kDa N-glycosylated protein encoded by ORF4, a 45-50 kDa N-glycosylated protein encoded by ORF3 and a 29-30 kDa N-glycosylated protein encoded by ORF2. A nomenclature for these structural proteins is proposed.
Meulenberg
J J
JJ
Institute for Animal Science and Health, Lelystad, The Netherlands. j.j.m.meulenberg@id.dlo.nl
Petersen den Besten
A
A
de Kluyver
E
E
van Nieuwstadt
A
A
Wensvoort
G
G
Moormann
R J
RJ
D000818:Animals; D018018:Arterivirus / Q000145:classification / Q000235:genetics; D005060:Europe; D016679:Genome, Viral; D009656:North America; D019251:Nucleocapsid / Q000235:genetics; D016366:Open Reading Frames; D019318:Porcine Reproductive and Respiratory Syndrome; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics; D015678:Viral Structural Proteins / Q000235:genetics
D014759:Viral Envelope Proteins; D015678:Viral Structural Proteins