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Mesonivirus
''Mesoniviridae'' is a family of enveloped, positive-strand RNA viruses in the order ''Nidovirales'' which infect mosquitoes. The family is named after the size of the genomes relative to other nidoviruses, with ''meso-'' coming from the Greek word ''mesos'', which means medium, and -''ni'' being an abbreviation of ''nido''. History The family is relatively new, having only been discovered in 2011. The first virus, which was named ''Nam Dinh virus'', was found in the Vietnamese province of Nam Định. The second virus, named ''Cavally virus'', was then found in Côte d'Ivoire. These two viruses were later found to be of the same species. A third member of this first species, named ''Dak Nong virus'', was later found in ''Culex tritaeniorhynchus'' populations in Vietnam. In 2013, four more mesoniviruses were discovered in mosquito populations, all within Côte d'Ivoire, and in 2014 four mesoniviruses were discovered in mosquito populations in Australia, Indonesia, and Thailand. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ORF1ab
ORF1ab (also ORF1a/b) refers collectively to two open reading frames (ORFs), ORF1a and ORF1b, that are conserved in the genomes of nidoviruses, a group of viruses that includes coronaviruses. The genes express large polyproteins that undergo proteolysis to form several nonstructural proteins with various functions in the viral life cycle, including proteases and the components of the replicase-transcriptase complex (RTC). Together the two ORFs are sometimes referred to as the replicase gene. They are related by a programmed ribosomal frameshift that allows the ribosome to continue translating past the stop codon at the end of ORF1a, in a -1 reading frame. The resulting polyproteins are known as pp1a and pp1ab. Expression ORF1a is the first open reading frame at the 5' end of the genome. Together ORF1ab occupies about two thirds of the genome, with the remaining third at the 3' end encoding the structural proteins and accessory proteins. It is translated from a 5' capped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replicase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses with no DNA stage including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
