If/how these genetic changes influence the spread of monkeypox is unclear. However, evidence suggests that MPV has acquired nearly 50 mutations compared to strains detected in 2018-2019. Poxviruses typically acquire about 1-2 mutations per year. The enzymes involved in DNA viral replication (i.e., DNA polymerase) are better at proofreading and fixing errors than those in RNA viral replication (i.e., RNA polymerase). DNA viruses, like MPV, do not mutate as freely as RNA viruses. ![]() There are 2 known viral clades of MPV: the Congo Basin clade and the less virulent West African clade, which underlies current outbreaks in non-endemic countries. The increased transmissibility of Omicron is tied to a slew of S protein mutations that regulate binding to ACE2 and promote the ability to evade host antibodies. When 2022 rolled around, Omicron, which spreads easier from person-to-person, replaced Delta as the most dominant variant. In 2021, the SARS-CoV-2 Delta variant dominated the pandemic landscape. This has been apparent throughout the COVID-19 pandemic. As a result, random mutations develop that can, if beneficial for viral fitness, quickly become widespread. However, while this may slow the acquisition of mutations in SARS-CoV-2, it does not stop them altogether. Unlike other RNA viruses, coronaviruses do have an enzyme (i.e., an exoribonuclease) with some proofreading ability. RNA polymerase, which copies the viral genome, lacks the ability to catch and fix replication errors. RNA viruses, like SARS-CoV-2, can be sloppy replicators. The differences in the genomes of SARS-CoV-2 and MPV have important evolutionary ramifications. However, rather than a single protein, poxviruses use 11 to 12 transmembrane proteins to fuse with host cells, likely binding glycosaminoglycans or laminin on the cell surface. Like SARS-CoV-2, MPV has surface proteins that facilitate its entry into host cells. Its double-stranded DNA genome is encapsulated in a core containing enzymes needed for replication and evasion of host immune defenses. MPV is a member of the Poxviridiae family-the virus is enveloped, brick shaped and large ( 220-450 nm long). S proteins bind to host cells via angiotensin-converting enzyme 2 (ACE2), a protein ubiquitously expressed by organs throughout the human body, to initiate infection. It is small ( ~100 nm in diameter), spherical and decorated with a porcupine-like sheath of spike (S) proteins. SARS-CoV-2, like all coronaviruses, is an enveloped single-stranded RNA virus. Structurally speaking, SARS-CoV-2 (the cause of COVID-19) and monkeypox virus (MPV) are very different. ![]() ![]() SARS-CoV-2 and Monkeypox Virus: Structure and Evolution Structure and Genome Source: American Society for Microbiology
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