Brulé H, Grosjean H, Giegé R, Florentz C
UPR 9002 du CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France.
Biochimie. 1998 Dec;80(12):977-85. doi: 10.1016/s0300-9084(99)80003-0.
tRNA post-transcriptional modification enzymes of Xenopus laevis were proposed previously to belong to two major groups according to their sensitivity to structural perturbations in their substrates. To further investigate the structural variations tolerated by these enzymes, the tRNA-like domain of turnip yellow mosaic virus RNA (88 nucleotides in length) has been microinjected into the oocytes of Xenopus laevis. This RNA possesses 12 potential target nucleotides for modification within a structure including a pseudoknotted folding, an extended anticodon stem, and unusual D-loop/T-loop interactions. Results indicate that only cytosine-42, a position equivalent to C-49 in canonical tRNAs, was quantitatively modified into m5C in the microinjected RNA. Modification was detected to high levels, indicating that at least one enzyme tolerates non-canonical structural features.
非洲爪蟾的tRNA转录后修饰酶先前根据其对底物结构扰动的敏感性被分为两大类。为了进一步研究这些酶所能耐受的结构变异，芜菁黄花叶病毒RNA的tRNA样结构域（长度为88个核苷酸）已被显微注射到非洲爪蟾的卵母细胞中。该RNA在一个包含假结折叠、延伸的反密码子茎以及异常的D环/T环相互作用的结构内有12个潜在的修饰靶核苷酸。结果表明，在显微注射的RNA中，只有胞嘧啶-42（相当于标准tRNA中的C-49位置）被定量修饰为5-甲基胞嘧啶。检测到高水平的修饰，表明至少有一种酶能耐受非标准的结构特征。
