Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Translation of the yeast retrotransposon Ty1 TYA1(gag)-TYB1(pol) gene occurs by a +1 ribosomal frameshifting event at the sequence CUU AGG C. Because overexpression of a low abundance tRNA-Arg(CCU) encoded by the HSX1 gene resulted in a reduction in Ty1 frameshifting, it was suggested that a translational pause at the AGG-Arg codon is required for optimum frameshifting. The present work shows that the absence of tRNA-Arg(CCU) affects Ty1 transposition, translational frameshifting, and accumulation of mature TYB1 proteins. Transposition of genetically tagged Ty1 elements decreases at least 50-fold and translational frameshifting increases 3-17-fold in cells lacking tRNA-Arg(CCU). Accumulation of Ty1-integrase and Ty1-reverse transcriptase/ribonuclease H is defective in an hsx1 mutant. The defect in Ty1 transposition is complemented by the wild-type HSX1 gene or a mutant tRNA-Arg(UCU) gene containing a C for T substitution in the first position of the anticodon. Overexpression of TYA1 stimulates Ty1 transposition 50-fold above wild-type levels when the level of transposition is compared in isogenic hsx1 and HSX1 strains. Thus, the HSX1 gene determines the ratio of the TYA1 to TYA1-TYB1 precursors required for protein processing or stability, and keeps expression of TYB1 a rate-limiting step in the retrotransposition cycle.
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PMID:A rare tRNA-Arg(CCU) that regulates Ty1 element ribosomal frameshifting is essential for Ty1 retrotransposition in Saccharomyces cerevisiae. 824 96

The aim of this study was to compare the performance of two commercial drug-resistance HIV-1genotyping kits: LiPA (Innogenetics, Belgium) and TruGene (Visible Genetics, Canada). Samples from 103 HIV-1 infected individuals from Argentina were studied. The average correlation between the two methods was 92.81%. More codons could be analysed by TruGene than by LiPA (610/618 and 541/618 codons, respectively). The sequences of the samples and the LiPA probes were aligned showing that a silent mutation at codon 72 (AGA-->AGG) of the HIV-1 reverse transcriptase, which was not recognised by the LiPA probes, was present in 35/36 non-reactive samples for position 74. The overall prevalence of this polymorphism in the population studied was 39.81%. When sequences from different parts of the world were analysed 189/3395 (5.63%) carried the mutation at codon 72, while 23/133 (17.29%) of the sequences from Latin America (excluding Argentina) had this mutation. In both cases, the prevalence of this polymorphism in the Argentinean population was significantly higher. This highlights the importance of carrying out studies on the performance of genotyping kits outside the United States and Europe, especially in areas where non-B HIV-1 subtypes are prevalent.
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PMID:A highly prevalent polymorphism at codon 72 of HIV-1 reverse transcriptase in Argentina prevents hybridization reaction at codon 74 in the LiPA genotyping test. 1133 43

Human immunodeficiency virus type 1 (HIV-1) is characterized by high genetic diversity. Current antiretroviral (ARV) drug resistance genotyping assays have been designed on the basis of the most prevalent sequence patterns circulating in the United States and Europe, which belong to the B subtype. However, little is known about their performance on non-B subtype samples. In Argentina, circulating forms have been characterized as subtypes B, C, F, and B/F recombinant forms. Our aim was to analyze the association between the genetic diversity of HIV-1 forms circulating in Argentina and the lack of reactivity at codon 74 in an ARV drug resistance hybridization-based assay. Samples taken from 93 HIV-1-infected individuals of Buenos Aires, Argentina were studied. The reverse transcriptase (RT) region of HIV-1 was genotypically assessed by a line probe assay (INNO-LiPA HIV-1 RT; Innogenetics, Ghent, Belgium) and automatic sequencing (TruGene and OpenGene; Visible Genetics, Toronto, Canada). Phylogenetic and intersubtype recombination analyses were carried out, showing that 52 of 93 (55.9%) samples belonged to subtype B, whereas 41 of 93 (44.1%) showed a (5') F1/B (3') subtype recombinant genomic structure. For codon 74 in the LiPA test, 4 of 52 (7.7%) B-subtype samples were nonreactive, whereas 27 of 41 (65.9 %) F1/B recombinant samples showed a nonreacting result, indicating a significant difference in the subtype distribution of the nonreacting samples. The presence of a synonymous polymorphism at codon 72 of RT (AGA --> AGG) associated with the lack of reaction at codon 74 in LiPA, was more prevalent in F1/B subtype recombinant samples (p < 0.001). The present data indicate that HIV-1 genetic diversity is a major obstacle for ARV drug resistance hybridization-based assays.
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PMID:HIV type 1 genetic diversity is a major obstacle for antiretroviral drug resistance hybridization-based assays. 1167 54

We propose that a nucleotide template-based mechanism facilitates the acquisition of the K65R mutation in subtype C human immunodeficiency virus type 1 (HIV-1). Different patterns of DNA synthesis were observed using DNA templates from viruses of subtype B or C origin. When subtype C reverse transcriptase (RT) was employed to synthesize DNA from subtype C DNA templates, preferential pausing was seen at the nucleotide position responsible for the AAG-to-AGG K65R mutation. This did not occur when the subtype B RT and template were used. Template factors can therefore increase the probability of K65R development in subtype C HIV-1.
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PMID:Template usage is responsible for the preferential acquisition of the K65R reverse transcriptase mutation in subtype C variants of human immunodeficiency virus type 1. 1907 30