Within each viral particle, retroviruses package two copies of a single-stranded RNA genome of about 10 kb. All of the viral genomes contain three major genes, arranged in the order: 5 ́-gag–pol–env-3 ́, and some retroviruses may also have accessory genes (e.g. vif, vpr, tax, etc...). Structural proteins such as MA (matrix protein), CA (capsid protein) and NC (nucleocapsid protein) are encoded wi...

In 1961, Howard Temin began to gather evidence that was inconsistant with the central dogma. Temin, who devoted his life to studying RNA tumor viruses (now known as retroviruses), focused his early work on Rous sarcoma virus (RSV). This RNA virus is capable of transforming normal cells into cancerous cells. Temin felt the best explanation for the virus’s behavior was a model whereby the virus r...

I n the past two decades, intense efforts have been devoted to uncovering the mechanisms responsible for the maintenance of telomeres in eukaryotic cells. These efforts have led to the identification of an unusual reverse transcriptase (RT), named telomerase, that uses an integral RNA subunit as template to synthesize a short reiterated sequence at the ends of eukaryotic chromosomes (Fig. 1A) (...

Currently, 16 antiretroviral drugs are approved for treatment of HIV infection. However, even the best currently available regimens pose challenges with regard to adherence, toxicity, antiviral activity, and resistance. New drug development thus confronts the need for improved convenience and tolerability, reduced toxicity, and improved activity against both wild-type and drug-resistant viruses...

Successful disease management requires a rapid and sensitive diagnosis method that can recognize early infection even before the manifestation of its clinical signs. The only available field diagnostic tests for foot-and-mouth disease (FMD) are lateral flow devices, commonly known as chromatographic strips. Low sensitivity and inability to detect FMD virus (FMDV) at the serotype level are limit...

the biological mechanisms of tooth movement are based on the response of periodontal tissues to mechanical forces. the final result of these responses is remodeling of the extracellular matrix. tissue reactions may vary depending upon the type, magnitude and duration of the applied forces. the purpose of the present study was to analyze the effects of centrifugal force on the transcription of c...

background human enteroviruses are members of picornaviridae family; they are non-enveloped, icosahedral viruses with positive rna as genome. echovirus 30 is an important member of enteroviruses that is recognized in outbreaks of enterovirus meningitis. objectives the aim of this study was to determine relative frequency of echovirus 30 as an important agent of aseptic meningitis among children...

background and aims: the causal agents of viral lettuce big vein disease are two viruse, lettuce big vein associated virus (varicosavirus) and mirafiori lettuce virus (ophiovirus). these viruses have coat proteins of similar size but have different morphologies and serologically unrelated.the purpose of this study was to distinguish and detect lbvav and milv in lettuce fields in tehran province...

The small RNAs contained in virions of avian leukosis and sarcoma viruses are a virus-specific subset of the total small RNA population of the host cell. The reverse transcriptase protein must be present in the budding virion for this selection to take place. Virions of the alpha form of the Bryan strain of Rous sarcoma virus, which lack detectable reverse transcriptase, incorporated an unselec...