Severe acute respiratory syndrome–related coronavirus is a species of coronavirus that infects humans, bats and certain other mammals. It is an enveloped positive-sense single-stranded RNA virus that enters its host cell by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. It is a member of the genus Betacoronavirus and subgenus Sarbecovirus.
Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including mammals and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30-nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis.
Rubella virus (RuV) is the pathogenic agent of the disease rubella, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to higher plants.
Tobamovirus is a genus of positive-strand RNA viruses in the family Virgaviridae. Many plants, including tobacco, potato, tomato, and squash, serve as natural hosts. Diseases associated with this genus include: necrotic lesions on leaves. The name Tobamovirus comes from the host and symptoms of the first virus discovered.
Ribosome shunting is a mechanism of translation initiation in which ribosomes bypass, or "shunt over", parts of the 5' untranslated region to reach the start codon, enabling viruses to have more information than usual in an mRNA molecule. Some viral RNAs have been shown to use ribosome shunting as a more efficient form of translation during certain stages of viral life cycle or when translation initiation factors are scarce. Some viruses known to use this mechanism include adenovirus, Sendai virus, human papillomavirus, duck hepatitis B pararetrovirus, rice tungro bacilliform viruses, and cauliflower mosaic virus. In these viruses the ribosome is directly translocated from the upstream initiation complex to the start codon (AUG) without the need to unwind RNA secondary structures.
Nicotiana benthamiana is a close relative of tobacco and species of Nicotiana indigenous to Australia.
Tomato bushy stunt virus (TBSV) is a virus that is the type species of the tombusvirus family. It was first reported in tomatoes in 1935 and primarily affects vegetable crops, though it is not generally considered an economically significant plant pathogen. Depending upon the host, TBSV causes stunting of growth, leaf mottling, and deformed or absent fruit. The virus is likely to be soil-borne in the natural setting, but can also transmitted mechanically, for example through contaminated cutting tools. TBSV has been used as a model system in virology research on the life cycle of plant viruses, particularly in experimental infections of the model host plant Nicotiana benthamiana.
Potyvirus is a genus of viruses in the family Potyviridae. Plants serve as natural hosts. There are currently 183 species in this genus including the type species Potato virus Y. The genus is named after the type virus. Potyviruses account for ~30% of the currently known plant viruses. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural and ornamental crops. More than 200 species of aphids spread potyviruses and most are from the subfamily Aphidinae.
Agroinfiltration is a method used in plant biology and especially lately in plant biotechnology to induce transient expression of genes in a plant, or isolated leaves from a plant, or even in cultures of plant cells, in order to produce a desired protein. In the method, a suspension of Agrobacterium tumefaciens is introduced into a plant leaf by direct injection or by vacuum infiltration, or brought into association with plant cells immobilised on a porous support, whereafter the bacteria transfer the desired gene into the plant cells via transfer of T-DNA. The main benefit of agroinfiltration when compared to the more traditional plant transformation is speed and convenience, although yields of the recombinant protein are generally also higher and more consistent.
In molecular biology, the coronavirus frameshifting stimulation element is a conserved stem-loop of RNA found in coronaviruses that can promote ribosomal frameshifting. Such RNA molecules interact with a downstream region to form a pseudoknot structure; the region varies according to the virus but pseudoknot formation is known to stimulate frameshifting. In the classical situation, a sequence 32 nucleotides downstream of the stem is complementary to part of the loop. In other coronaviruses, however, another stem-loop structure around 150 nucleotides downstream can interact with members of this family to form kissing stem-loops and stimulate frameshifting.
This family represents the internal ribosome entry site (IRES) of the hepatitis A virus. HAV IRES is a 450 nucleotide long sequence located in the 735 nt long 5’ UTR of Hepatitis A viral RNA genome. IRES elements allow cap and end-independent translation of mRNA in the host cell. The IRES achieves this by mediating the internal initiation of translation by recruiting a ribosomal 40S pre-initiation complex directly to the initiation codon and eliminates the requirement for eukaryotic initiation factor, eIF4F.
HIV ribosomal frameshift signal is a ribosomal frameshift (PRF) that human immunodeficiency virus (HIV) uses to translate several different proteins from the same sequence.
Pepper mottle virus (PepMoV) is a plant pathogenic virus in the genus Potyvirus and the virus family Potyviridae. Like other members of the Potyvirus genus, PepMV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 737 nm in length. Isolates of this virus has been completely sequenced and its RNA is 9640 nucleotides long. This virus is transmitted by several species of aphids in a nonpersitant manner and by mechanical inoculation.
Sweet potato feathery mottle virus (SPFMV) is a member of the genus Potyvirus in the family Potyviridae. It is most widely recognized as one of the most regularly occurring causal agents of sweet potato viral disease (SPVD) and is currently observed in every continent except Antarctica. The number of locations where it is found is still increasing; generally, it is assumed that the virus is present wherever its host is. The virus has four strains that are found in varying parts of the world.
Ribosomal frameshifting, also known as translational frameshifting or translational recoding, is a biological phenomenon that occurs during translation that results in the production of multiple, unique proteins from a single mRNA. The process can be programmed by the nucleotide sequence of the mRNA and is sometimes affected by the secondary, 3-dimensional mRNA structure. It has been described mainly in viruses, retrotransposons and bacterial insertion elements, and also in some cellular genes.
Sobemovirus is a genus of viruses. Plants serve as natural hosts. There are currently 14 species in this genus including the type species Southern bean mosaic virus. Diseases associated with this genus include: mosaics and mottles.
A slippery sequence is a small section of codon nucleotide sequences that controls the rate and chance of ribosomal frameshifting. A slippery sequence causes a faster ribosomal transfer which in turn can cause the reading ribosome to "slip." This allows a tRNA to shift by 1 base (−1) after it has paired with its anticodon, changing the reading frame. A −1 frameshift triggered by such a sequence is a Programmed −1 Ribosomal Frameshift. It is followed by a spacer region, and an RNA secondary structure. Such sequences are common in virus polyproteins.
Coronavirus genomes are positive-sense single-stranded RNA molecules with an untranslated region (UTR) at the 5′ end which is called the 5′ UTR. The 5′ UTR is responsible for important biological functions, such as viral replication, transcription and packaging. The 5′ UTR has a conserved RNA secondary structure but different Coronavirus genera have different structural features described below.
Rio Negro virus is an alphavirus that was first isolated in Argentina in 1980. The virus was first called Ag80-663 but was renamed to Rio Negro virus in 2005. The virus is a member of the Venezuelan equine encephalitis complex (VEEC), which are a group of alphaviruses in the Americas that have the potential to emerge and cause disease. Closely related viruses include Mucambo virus and Everglades virus.
