A structure-activity relationship (SAR) study was carried out to identify novel, small molecular weight compounds which induce readthrough of premature termination codons. In particular, analogs of RTC13, 1, were evaluated. In addition, hypothesizing that these compounds exhibit their activity by binding to the ribosome, we prepared the hybrid analogs 13 containing pyrimidine bases and these al...

The lsa gene confers intrinsic resistance to lincosamides and streptogramins A in Enterococcus faecalis, probably by active efflux. The lsa-like genes of two clinical isolates of E. faecalis susceptible to lincosamides and dalfopristin contained mutations that produced premature termination codons. Revertant mutants were obtained by selection on agar plates containing clindamycin.

Two forms of post-transcriptional control direct differential expression of the Saccharomyces cerevisiae genes encoding the AP1-like transcription factors Yap1p and Yap2p. The mRNAs of these genes contain respectively one (YAP1 uORF) and two (YAP2 uORF1 and uORF2) upstream open reading frames. uORF-mediated modulation of post-termination events on the 5'-untranslated region (5'-UTR) directs dif...

The Nonsense-Mediated mRNA Decay (NMD) pathway mediates the rapid degradation of mRNAs that contain premature stop mutations in eukaryotic organisms. It was recently shown that mutations in three yeast genes that encode proteins involved in the NMD process, UPF1, UPF2, and UPF3, also reduce the efficiency of translation termination. In the current study, we compared the efficiency of translatio...

The Nonsense-Mediated mRNA Decay (NMD) pathway mediates the rapid degradation of mRNAs that contain premature stop mutations in eukaryotic organisms. It was recently shown that mutations in three yeast genes that encode proteins involved in the NMD process, UPF1, UPF2, and UPF3, also reduce the efficiency of translation termination. In the current study, we compared the efficiency of translatio...

A survey of 196 protein-coding chloroplast DNA sequences demonstrated the preference for AUG and UAA codons for initiation and termination of translation, respectively. As in prokaryotes at every nucleotide position from -25 to +25 (AUG is +1 to +3) and for 25 nucleotides 5' and 3' to the termination codon an A or U is predominant, except for C at +5 and G at +22. A Shine-Dalgarno (SD) sequence...

The efficiency of translation termination is influenced by local contexts surrounding stop codons. In Saccharomyces cerevisiae, upstream and downstream sequences act synergistically to influence the translation termination efficiency. By analysing derivatives of a leaky stop codon context, we initially demonstrated that at least six nucleotides after the stop codon are a key determinant of read...

mRNA translation in many ciliates utilizes variant genetic codes where stop codons are reassigned to specify amino acids. To characterize the repertoire of ciliate genetic codes, we analyzed ciliate transcriptomes from marine environments. Using codon substitution frequencies in ciliate protein-coding genes and their orthologs, we inferred the genetic codes of 24 ciliate species. Nine did not m...