Search PubMed⌕ Search

Biomedical subjects

V I Agol

Publications and source records attributed to V I Agol.

At least 145 records · Page 8Linked to original sources
PubMed1968

Mechanism of resistance to enteroviruses of some primate cells in tissue culture.

Two cell lines, M10-45-2 and L-41, were studied, each of which possessed specific resistance either to poliovirus or to coxsackievirus. Infection of M10-45-2 cells with poliovirus ribonucleic acid (RNA) and L-41 cells with infectious coxsackievirus RNA was accompanied by production of complete viruses in each of the resistant cell lines. During incubation of the cells with the virus to which they were resistant, the amount of infectious virus did not decrease. Treatment with glycine-HCl buffer solution (pH 2.5) of resistant M10-45-2 cells after incubation with poliovirus at 0 C did not result in recovery of infectious virus, although such release did take place after treatment of sensitive M10 cells. Infection of resistant cells with virus containing poliovirus RNA and coxsackievirus proteins resulted in production of poliovirus in M10-45-2 cells but not in L-41 cells. The resistant cells are apparently unable to adsorb the virus to which they are resistant.

Adsorption↗
PubMedDate not supplied

[Translational control of the picornavirus phenotype].

Picornaviruses are small animal viruses with positive-stranded genomic RNA, which is translated using cap-independent internal translation initiation. The key role in this is played by cis elements of the 5'-untranslated region (5'-UTR) and, in particular, by the internal ribosome entry site (IRES). The function of translational cis elements requires both canonical translation initiation factors (eIFs) and additional IRES trans-acting factors (ITAFs). All known ITAFs are cell RNA-binding proteins which play a variety of functions in noninfected cells. Specific features of translational cis elements substantially affect the phenotype and, in particular, tissue tropism and pathogenic properties of picornaviruses. It is clear that, in some cases, the molecular mechanism of this is a change in interactions between viral cis elements and ITAFs. The properties and tissue distribution of ITAFs may determine the biological properties of other viruses that also use the IRES-dependent translation initiation. Since this mechanism is also involved in translation of several cell mRNAs, ITAF may contribute to the regulation of the most important aspects of the living activity in noninfected cells.

Picornaviridae↗
PubMedDate not supplied

[Genomic instability in picornaviruses].

Picornaviruses are small animal RNA viruses and include wtiological agents of poliomyelitis, foot and mouse disease, hepatitis A, etc. Replication of their genome results in many mutations, which are close in number to a viability threshold. Hence every virus population contains a great variety of genomes and represents a quasispecies. Covalent rearrangements (deletions, insertions, recombination) also contribute to genome variation and arise by replicative and nonreplicative mechanisms, which are still poorly understood. Only a minor fraction of all new changes is fixed during evolution. The fixation is based on two principally different ways of selection: with (positive and negative selection) and without (random selection of nonrepresentative variants) regard to the phenotype. In natural evolution of picornaviruses, the latter way is prevalent, and most fixed mutations are phenotypically neutral. To understand the mechanisms of evolution, it is necessary to evaluate the biological significance of particular genetic changes. Several new approaches to this problem have recently been proposed.

Biological Evolution↗
PubMedDate not supplied

[Viral infectious and cell differentiation].

The dependence of viral reproduction and success of viral infection on cell differentiation is briefly reviewed at the example of picornaviruses--small RNA viruses of animals. In particular, the role of the cell factors in viral tropism, control of viral RNA translation, and the pattern of infected cell death are discussed.

Animals↗
PubMedDate not supplied

[Probable compact structure of a cis-active translation element in the 5'-untranslated region of the enterovirus and rhinovirus genome].

A previously proposed consensus secondary structure model of the internal portion of the 5'-untranslated region of the enterovirus and rhinovirus genomes encompassing the cis-acting translational control element was extended and detailed on the basis of comparative sequence data and biochemical analysis. Using this model as a reference, numerous pairs of apparently single-stranded noncontiguous nucleotide stretches with a potential to form inter-domain tertiary bonds were shown to be conserved among the respective segments of all the known enterovirus and rhinovirus RNAs. It is suggested that at least some of these inter-domain bonds may actually exist, resulting in a compact, quasi-globular, perhaps "two-lobe" folding of the translational control element. Such an organization should have important functional implications.

Base Sequence↗
PubMedDate not supplied

[Variable mechanisms of RNA-recombination].

Recombination is widespread among RNA viruses but underlying mechanisms remain poorly understood. Until recently, replicative template switching was considered the only possible mechanism of RNA recombination but new evidence suggests that other variants of replicative mechanisms may also exist. In addition, nonreplicative recombination (i.e., joining of preexisting molecules) of genomes of RNA viruses is possible. Recombination is an efficient tool contributing to both variability and stability of the viral RNA genomes. Nonreplicative joining of RNA pieces in the form of trans-splicing is an important physiological mechanism in at least certain organisms. It is conceivable that RNA-recombination has contributed, and perhaps is still contributing, to the evolution of DNA genomes.

Allolevivirus↗
PubMedDate not supplied

[How the poliovirus changes a cell].

The paper considers different aspects of a cell response to poliovirus infection, such as transcriptional and translational changes, modification of membranes and their transport, impairment in the nucleoplasmic barrier, and the mechanisms of infected cell death.

Animals↗
PubMedDate not supplied

[Internal initiation of translation in eukaryotes].

Fundamental differences between the most commonly exploited mechanisms of translation initiation in prokaryotic and eukaryotic systems are briefly considered. A non-canonical, "prokaryotic-like", cap-independent internal initiation of translation by eukaryotic systems, as exemplified by the picornaviral RNAs, is discussed in more details.

Eukaryotic Cells↗
PubMedDate not supplied

[Recombination between RNA genomes].

Evidence for the intermolecular recombination between the RNA genomes of picornaviruses and coronaviruses as well as current models of the mechanisms of these phenomena are reviewed. Biological implications of the recombination between RNA genomes are briefly discussed. Examples of the recombinant analysis of the viral genome functions are given.

Coronaviridae↗