Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0149514 (bronchitis)
 6,902 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retroviruses whose gag and pol genes are in the same reading frame depend upon approximately 5% read-through of the gag UAG termination codon to make the gag-pol polyprotein. For murine leukemia virus, this read-through is dependent on a pseudoknot located eight nucleotides 3' of the UAG. Other retroviruses whose gag and pol genes are in the same frame can potentially form similar pseudoknots 3' of their UAG codons. Beyond the similar secondary structures, there is strong sequence conservation in the spacer region and in loop 2 of the pseudoknots. The detrimental effects of substitutions of several of these conserved spacer and loop 2 nucleotides in the murine leukemia virus sequence show their importance for the read-through process. The importance of specific nucleotides in loop 2 of the pseudoknot contrasts with the flexibility of sequence in loop 2 of the most intensively studied frameshift-promoting pseudoknot which occurs in infectious bronchitis virus. Two nucleotides in loop 2 of the murine leukemia virus pseudoknot, which were shown to be important by mutagenic analysis, display hypersensitivity to the single-strand specific nuclease, S1. They are likely to be particularly accessible or are in an unusually reactive conformation.
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PMID:Pseudoknot-dependent read-through of retroviral gag termination codons: importance of sequences in the spacer and loop 2. 807 9

At the April 1992, mid-term meeting of the International Committee on Taxonomy of Viruses (ICTV) a proposal from the Coronaviridae Study Group (CSG) to include the torovirus genus in the Coronaviridae was accepted. Following another proposal, the arterivirus genus was removed from the Togaviridae but not assigned to another family. The arteriviruses have some features in common with the Coronaviridae but also have major differences. After much debate, culminating in September 1992, it was decided that the CSG would not recommend inclusion of arterivirus in the Coronaviridae. It was agreed that (a) the nomenclature used for coronavirus genes, mRNAs and polypeptides (Cavanagh et al., 1990) should be used for toroviruses, (b) that the small (about 100 amino acids) membrane-associated protein, which is distinct from the integral membrane glycoprotein M, associated with virions of infectious bronchitis (Liu & Inglis, 1991) and transmissible gastroenteritis (Godet et al., 1992) coronaviruses would be referred to by the acronym sM (lower case 's') and (c) that 'pol' (polymerase) should be used as a working term for gene 1, which comprises open reading frames (ORFs) 1a and 1b in both genera of the Coronaviridae.
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PMID:The Coronaviridae now comprises two genera, coronavirus and torovirus: report of the Coronaviridae Study Group. 820 39

Here we investigated ribosomal pausing at sites of programmed -1 ribosomal frameshifting, using translational elongation and ribosome heelprint assays. The site of pausing at the frameshift signal of infectious bronchitis virus (IBV) was determined and was consistent with an RNA pseudoknot-induced pause that placed the ribosomal P- and A-sites over the slippery sequence. Similarly, pausing at the simian retrovirus 1 gag/pol signal, which contains a different kind of frameshifter pseudoknot, also placed the ribosome over the slippery sequence, supporting a role for pausing in frameshifting. However, a simple correlation between pausing and frameshifting was lacking. Firstly, a stem-loop structure closely related to the IBV pseudoknot, although unable to stimulate efficient frameshifting, paused ribosomes to a similar extent and at the same place on the mRNA as a parental pseudoknot. Secondly, an identical pausing pattern was induced by two pseudoknots differing only by a single loop 2 nucleotide yet with different functionalities in frameshifting. The final observation arose from an assessment of the impact of reading phase on pausing. Given that ribosomes advance in triplet fashion, we tested whether the reading frame in which ribosomes encounter an RNA structure (the reading phase) would influence pausing. We found that the reading phase did influence pausing but unexpectedly, the mRNA with the pseudoknot in the phase which gave the least pausing was found to promote frameshifting more efficiently than the other variants. Overall, these experiments support the view that pausing alone is insufficient to mediate frameshifting and additional events are required. The phase dependence of pausing may be indicative of an activity in the ribosome that requires an optimal contact with mRNA secondary structures for efficient unwinding.
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PMID:Ribosomal pausing at a frameshifter RNA pseudoknot is sensitive to reading phase but shows little correlation with frameshift efficiency. 1171 98