In Sindbis, Venezuelan equine encephalitis and related alphaviruses, the polymerase is translated as a fusion with other non-structural proteins via readthrough of a UGA stop codon. Surprisingly, earlier work reported that the signal for efficient readthrough comprises a single cytidine residue 3'-adjacent to the UGA. However, analysis of variability at synonymous sites revealed strikingly enhanced conservation within the ∼ 150 nt 3'-adjacent to the UGA, and RNA folding algorithms revealed the potential for a phylogenetically conserved stem-loop structure in the same region.
View Article and Find Full Text PDFHalf the ribosomes translating the mRNA for phage T4 gene 60 topoisomerase subunit bypass a 50 nucleotide coding gap between codons 46 and 47. The pairing of codon 46 with its cognate peptidyl-tRNA anticodon dissociates, and following mRNA slippage, peptidyl-tRNA re-pairs to mRNA at a matched triplet 5' adjacent to codon 47, where translation resumes. Here, in studies with gene 60 cassettes, it is shown that the peptidyl-tRNA anticodon does not scan the intervening sequence for potential complementarity.
View Article and Find Full Text PDFThe extent to which measures of working memory, cognitive speed, and verbal retrieval are associated with performance on tests of olfaction was evaluated in a sample of 138 older adults. Structural equation modeling techniques indicated that verbal retrieval difficulties significantly affect performance on the University of Pennsylvania Smell Identification Test (UPSIT). Further, poor working memory and slow cognitive speed significantly affect performance on the UPSIT and the phenyl ethyl alcohol threshold test.
View Article and Find Full Text PDFSelenoprotein P (Sepp1) has two domains with respect to selenium content: the N-terminal, selenium-poor domain and the C-terminal, selenium-rich domain. To assess domain function, mice with deletion of the C-terminal domain have been produced and compared with Sepp1-/- and Sepp1+/+ mice. All mice studied were males fed a semipurified diet with defined selenium content.
View Article and Find Full Text PDFThe synthesis of the protein antizyme requires a +1 ribosomal frameshift event. The frameshifting serves as a regulatory sensor. Antizyme homologs have been identified in diverse organisms ranging from yeast to human and characterized in a disparate subset.
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