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Rolling Hairpin Replication
Rolling hairpin replication (RHR) is a unidirectional, strand displacement form of DNA replication used by parvoviruses, a group of viruses that constitute the family ''Parvoviridae''. Parvoviruses have linear, single-stranded DNA (ssDNA) genomes in which the coding portion of the genome is flanked by telomeres at each end that form hairpin loops. During RHR, these hairpin loops repeatedly unfold and refold to change the direction of DNA replication so that replication progresses in a continuous manner back and forth across the genome. RHR is initiated and terminated by an endonuclease encoded by parvoviruses that is variously called NS1 or Rep, and RHR is similar to rolling circle replication, which is used by ssDNA viruses that have circular genomes. Before RHR begins, a host cell DNA polymerase converts the genome to a duplex form in which the coding portion is double-stranded and connected to the terminal hairpins. From there, messenger RNA (mRNA) that encodes the viral initiato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Replication
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA is made up of a double helix of two complementary strands. The double helix describes the appearance of a double-stranded DNA which is thus composed of two linear strands that run opposite to each other and twist together to form. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, a process referred to as semiconservative replication. As a result of semi-conservative rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promoter (genetics)
In genetics, a promoter is a sequence of DNA to which proteins bind to initiate transcription of a single RNA transcript from the DNA downstream of the promoter. The RNA transcript may encode a protein (mRNA), or can have a function in and of itself, such as tRNA or rRNA. Promoters are located near the transcription start sites of genes, upstream on the DNA (towards the 5' region of the sense strand). Promoters can be about 100–1000 base pairs long, the sequence of which is highly dependent on the gene and product of transcription, type or class of RNA polymerase recruited to the site, and species of organism. Promoters control gene expression in bacteria and eukaryotes. RNA polymerase must attach to DNA near a gene for transcription to occur. Promoter DNA sequences provide an enzyme binding site. The -10 sequence is TATAAT. -35 sequences are conserved on average, but not in most promoters. Artificial promoters with conserved -10 and -35 elements transcribe more slowly. All D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brevihamaparvovirus
''Brevihamaparvovirus'' is a genus of viruses in subfamily '' Hamaparvovirinae'' of the family ''Parvoviridae Parvoviruses are a family of animal viruses that constitute the family ''Parvoviridae''. They have linear, single-stranded DNA (ssDNA) genomes that typically contain two genes encoding for a replication initiator protein, called NS1, and the pr ...''. Mosquitoes serve as natural hosts. There are two species in this genus. Taxonomy The following two species are assigned to the genus: *'' Dipteran brevihamaparvovirus 1'' *'' Dipteran brevihamaparvovirus 2'' Structure Viruses in genus ''Brevihamaparvovirus'' are non-enveloped and have T=1 icosahedral symmetry. The diameter is around 21-22 nm. Genomes are linear, around 4kb in length. Life cycle Viral replication is nuclear. Entry into the host cell is achieved by attachment to host receptors, which mediates clathrin-mediated endocytosis. Replication follows the rolling-hairpin model. DNA-templated transcriptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iteradensovirus
''Iteradensovirus'' is a genus of viruses in the subfamily ''Densovirinae'' of the family ''Parvoviridae''. Insects serve as natural hosts. There are five species in this genus. Taxonomy The following five species are assigned to the genus: *''Lepidopteran iteradensovirus 1'' *''Lepidopteran iteradensovirus 2'' *''Lepidopteran iteradensovirus 3 Lepidoptera ( ) is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described specie ...'' *'' Lepidopteran iteradensovirus 4'' *'' Lepidopteran iteradensovirus 5'' Structure Viruses in ''Iteradensovirus'' are non-enveloped, with icosahedral and Round geometries, and T=1 symmetry. The diameter is around 21-22 nm. Genomes are linear, around 5kb in length. Life cycle Viral replication is nuclear. Entry into the host cell is achieved by attachment to host receptors, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
