O'Connor Michael
J. W. Wilson Laboratory, Department of Molecular and Cellular Biology and Biochemistry, 69 Brown Street, Brown University, Providence, RI 02912, USA. michael_o'
Nucleic Acids Res. 2002 Feb 1;30(3):759-65. doi: 10.1093/nar/30.3.759.
Increased expression of the CCU/CCA/CCG-decoding tRNA(Pr)(o)3 on a multicopy plasmid leads to suppression of several +1 frameshift mutations in Salmonella enterica serovar Typhimurium. Systematic analysis of the site of frameshifting indicates that excess tRNA(Pr)(o)3 promotes near-cognate decoding at CCC codons. Re-phasing of the reading frame can be achieved by a subsequent slippage of the tRNA onto a cognate codon in the +1 reading frame. Frameshifting appears to be due to an imbalance of CCC-cognate and near-cognate tRNAs, as the effect of excess tRNA(Pr)(o)3 on reading frame maintenance can be reversed by increasing simultaneously the concentration of the cognate tRNA(Pr)(o)2. Finally, the cmo5U modification present at position 34 of tRNA(Pr)(o)3, which allows this tRNA to decode CCU in addition to CCG and CCA, also affects frameshifting, indicating that the ability of the near-cognate tRNA to decode a cognate codon efficiently in the alternative reading frame is important for re-phasing of the reading frame.
在多拷贝质粒上增加CCU/CCA/CCG解码tRNA(Pr)(o)3的表达会导致鼠伤寒沙门氏菌中几个+1移码突变的抑制。对移码位点的系统分析表明，过量的tRNA(Pr)(o)3促进了CCC密码子处的近同源解码。阅读框的重新相位可通过tRNA随后滑入+1阅读框中的同源密码子来实现。移码似乎是由于CCC同源tRNA和近同源tRNA的不平衡所致，因为通过同时增加同源tRNA(Pr)(o)2的浓度，可以逆转过量tRNA(Pr)(o)3对阅读框维持的影响。最后，tRNA(Pr)(o)3第34位存在的cmo5U修饰，使该tRNA除了解码CCG和CCA外还能解码CCU，这也影响移码，表明近同源tRNA在替代阅读框中有效解码同源密码子的能力对于阅读框的重新相位很重要。
