A picornavirus is a virus belonging to the family Picornaviridae, a family of viruses in the order Picornavirales. Vertebrates, including humans, serve as natural hosts. Picornaviruses are nonenveloped viruses that represent a large family of small, cytoplasmic, plus-strand RNA (~7.5kb) viruses with a 30-nm icosahedral capsid. Its genome does not have a lipid membrane. Picornaviruses are found in mammals and birds. There are currently 80 species in this family, divided among 35 genera. Notable examples are Enterovirus, Aphthovirus, Cardiovirus, and Hepatovirus genera. The viruses in this family can cause a range of diseases including paralysis, meningitis, hepatitis and poliomyelitis. Picornaviruses are in Baltimore IV class. Their genome single-stranded (+) sense RNA is what functions as mRNA after entry into the cell and all viral mRNA synthesized is of genome polarity. The mRNA encodes RNA dependent RNA polymerase. This polymerase makes complementary minus strands of RNA, then uses them as templates to make more plus strands. So, an overview of the steps in picornavirus replication are in order: attachment, entry, translation, transcription/genome replication, assembly and exit.
In molecular biology and genetics, the sense of nucleic acid molecules is the nature of their roles and their complementary molecules' nucleic acid units' roles in specifying amino acids. Depending on the context within molecular biology, sense may have slightly different meanings.
Sindbis virus (SINV) is a member of the Togaviridae family, in the alphavirus subfamily. The virus was first isolated in 1952 in Cairo, Egypt. The virus is transmitted by mosquitoes SINV causes sindbis fever in humans and the symptoms include arthralgia, rash and malaise. Sindbis fever is most common in South and East Africa, Egypt, Israel, Philippines and parts of Australia. Sindbis virus is an "arbovirus" (arthropod-borne) and is maintained in nature by transmission between vertebrate (bird) hosts and invertebrate (mosquito) vectors. Humans are infected with Sindbis virus when bitten by an infected mosquito. SINV has been linked to Pogosta disease in Finland, Ockelbo disease in Sweden and Karelian fever in Russia.
The Bamboo mosaic potexvirus (BaMV) cis-regulatory element represents a cloverleaf-like cis-regulatory element found in the 3' UTR of the bamboo mosaic virus. This family is thought to play an important role in the initiation of minus-strand RNA synthesis and may also be involved in the regulation of viral replication.
The bamboo mosaic virus satellite RNA cis-regulatory element is an RNA element found in the 5' UTR of the genome of the bamboo mosaic virus. This element is thought to be essential for efficient RNA replication.
In molecular biology, the enteroviral 3' UTR element is an RNA structure found in the 3' UTR of various enteroviruses. The overall structure forms the origin of replication (OriR) for the initiation of (-) strand RNA synthesis. Pseudoknots have also been predicted in this structure.
The Enterovirus 5' cloverleaf cis-acting replication element is an RNA element found in the 5' UTR of Enterovirus genomes. The element has a cloverleaf like secondary structure and is known to be a multifunctional cis-acting replication element (CRE), required for the initiation of negative strand RNA synthesis.
Enterovirus cis-acting replication element is a small RNA hairpin in the coding region of protein 2C as the site in PV1(M) RNA that is used as the primary template for the in vitro uridylylation. The first step in the replication of the plus-stranded poliovirus RNA is the synthesis of a complementary minus strand. This process is initiated by the covalent attachment of uridine monophosphate (UMP) to the terminal protein VPg, yielding VPgpU and VPgpUpU.
The equine arteritis virus leader transcription-regulating sequence hairpin (LTH) is as RNA element that is thought to be a key structural element in discontinuous subgenomic RNA synthesis and is critical for leader transcription-regulating sequences (TRS) function. Similar structures have been predicted in other arteriviruses and coronaviruses.
The Potato virus X cis-acting regulatory element is a cis-acting regulatory element found in the 3' UTR of the Potato virus X genome. This element has been found to be required for minus strand RNA accumulation and is essential for efficient viral replication.
This family represents a rotavirus cis-acting replication element (CRE) found at the 3'-end of rotavirus mRNAs. The family is thought to promote the synthesis of minus strand RNA to form viral dsRNA.
The Rubella virus 3' cis-acting element RNA family represents a cis-acting element found at the 3' UTR in the rubella virus. This family contains three conserved step loop structures. Calreticulin (CAL), which is known to bind calcium in most eukaryotic cells, is able to specifically bind to the first stem loop of this RNA. CAL binding is thought to be related to viral pathogenesis and in particular arthritis which occurs frequently in rubella infections in adults and is independent of viral viability. All stem loop structures are thought to be important for efficient viral replication and deletion of stem loop three is known to be lethal.
Human rhinovirus internal cis-acting regulatory element (CRE) is a CRE from the human rhinoviruses. The CRE is located within the genome segment encoding the capsid proteins so is found in a protein coding region. The element is essential for efficient viral replication and it has been suggested that the CRE is required for initiation of minus-strand RNA synthesis.
Tombusvirus 3' UTR is an important cis-regulatory region of the Tombus virus genome.
Tombusvirus 5' UTR is an important cis-regulatory region of the Tombus virus genome.
The TCV hairpin 5 (H5) is an RNA element found in the turnip crinkle virus. This RNA element is composed of a stem-loop that contains a large symmetrical internal loop (LSL). H5 can repress minus-strand synthesis when the 3' side of the LSL pairs with the 4 bases at the 3'-terminus of the RNA(GCCC-OH).
The Upstream pseudoknot (UPSK) domain is an RNA element found in the turnip yellow mosaic virus, beet virus Q, barley stripe mosaic virus and tobacco mosaic virus, which is thought to be needed for efficient transcription. Disruption of the pseudoknot structure gives rise to a 50% drop in transcription efficiency. This element acts in conjunction with the Tymovirus/Pomovirus tRNA-like 3' UTR element to enhance translation.
Cis-acting replication elements bring together the 5' and 3' ends during replication of positive-sense single-stranded RNA viruses and double-stranded RNA viruses.
