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  • genomes
  • Microbes also comprise a method that makes use of CRISPR sequences to retain fragments from the genomes of viruses the micro organism have appear into contact with in past times, which allows them to block the virus's replication by way of a form of RNA interference. (ampblogs.com)
  • Of these, only two families have RNA genomes, and only five families are surrounded by an envelope. (wikipedia.org)
  • The genomes are linear, positive-sense, polycistronic, single-stranded RNA, and are about 20,000 nucleotides in length, with a 3' poly(A) tail and seven major open reading frames (ORFs). (wikipedia.org)
  • virions
  • Group: ssRNA(+) Order: Unassigned Family: Togaviridae Genus: Rubivirus Rubella virus The spherical virus particles (virions) of Togaviridae have a diameter of 50 to 70 nm and are covered by a lipid membrane (viral envelope), derived from the host cell membrane. (wikipedia.org)
  • One of these includes RNA replicase , which copies the viral RNA to form a double-stranded replicative form, in turn this directs the formation of new virions. (wikidoc.org)
  • virion
  • each virion can be transcribed to several positive-sense RNAs. (wikipedia.org)
  • In more details, replication of the virion consists of the following steps: A virion enters the host cell and releases its negative RNA into the cytoplasm. (wikipedia.org)
  • infection
  • As evidenced by the efficacy of the seasonal flu vaccine and the ongoing trials for an Ebola cure, pharmacological interventions to cure a ssRNA infection are few and far between. (outbreaknewstoday.com)
  • As such, purified RNA of a positive-sense virus can directly cause infection though it may be less infectious than the whole virus particle. (wikipedia.org)
  • virus
  • In a paper published ahead of print in the Proceedings of the National Academy of Sciences, researchers from the University of Leeds and the University of York have discovered a unique code in single stranded RNA viruses that dictate the packaging instructions of a fully formed virus, providing a potential drug therapy target. (outbreaknewstoday.com)
  • There are profound implications for future ssRNA virus research: "[This] is like finding a secret message within an ordinary news report and then being able to crack the whole coding system behind it," said Dr Roman Tuma, Reader in Biophysics at the University of Leeds. (outbreaknewstoday.com)
  • Although RNA usually mutates rapidly, recent work found that the SARS virus and related RNA viruses contain a gene that mutates very slowly. (wikidoc.org)
  • Positive sense ssRNA virus families. (brainscape.com)
  • Because the virus only has 2 initial RNAs, this is the simplest class of virus. (wikipedia.org)
  • Replication follows the positive stranded RNA virus replication model. (wikipedia.org)
  • Positive stranded RNA virus transcription is the method of transcription. (wikipedia.org)
  • In 1958, she speculated that the virus was hollow, not solid, and hypothesized that the RNA of TMV is single-stranded. (wikipedia.org)
  • sequence
  • During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript . (wikipedia.org)
  • The complementary RNA is created in the opposite direction, in the 5' → 3' direction, matching the sequence of the sense strand with the exception of switching uracil for thymine. (wikipedia.org)
  • The non -template (sense) strand of DNA is called the coding strand , because its sequence is the same as the newly created RNA transcript (except for the substitution of uracil for thymine). (wikipedia.org)
  • RNA polymerase, assisted by one or more general transcription factors, then selects a transcription start site in the transcription bubble, binds to an initiating NTP and an extending NTP (or a short RNA primer and an extending NTP) complementary to the transcription start site sequence, and catalyzes bond formation to yield an initial RNA product. (wikipedia.org)
  • transcription
  • RNA polymerase, together with one or more general transcription factors , binds to promoter DNA . (wikipedia.org)
  • As opposed to DNA replication , transcription results in an RNA complement that includes the nucleotide uracil (U) in all instances where thymine (T) would have occurred in a DNA complement. (wikipedia.org)
  • A temperature-dependent partial replication of specific regions of dsRNA could produce the first template-based generation of catalytic ssRNA, similar to the developmental gene transcription process. (beds.ac.uk)
  • The transition from ssRNA as the informational carrier to dsDNA is also mechanistically difficult since in order to maintain existing catalytic function, the concomitant evolution of a transcription system based on dsDNA is needed. (beds.ac.uk)
  • This is in contrast to a typical DNA-dependent RNA polymerase, which catalyzes the transcription of RNA from a DNA template. (wikipedia.org)
  • template
  • Further transition from a dsRNA to a dsDNA world could be based on minor mutations in template and substrate recognition sites of an RNA polymerase and would leave all existing processes intact. (beds.ac.uk)