Benhar I, Engelberg-Kulka H
Department of Molecular Biology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Cell. 1993 Jan 15;72(1):121-30. doi: 10.1016/0092-8674(93)90056-v.
The E. coli trpR gene encodes the 108 amino acid long trp repressor. We have previously shown that a +1 frameshifting event occurs during the expression of trpR. Here we show that the transition from the 0 to the +1 frame of trpR occurs by the bypassing of a 55 nt long segment of the trpR+1-lacZ mRNA. This bypassing event is not pretranslational, and it probably takes place during translation. Two adjacent elements are required: a specific sequence of trpR, which must be preceded by a nonspecific 5' end longer than 10 translatable codons. Unique to trpR-lacZ bypassing is that the 55 nt long region must be translated in frame 0 to enable bypassing into the +1 frame. Translational bypassing as a newly discovered mechanism of gene expression is discussed, and the possible existence of translational introns is suggested.
大肠杆菌trpR基因编码长度为108个氨基酸的色氨酸阻遏蛋白。我们之前已经表明，在trpR表达过程中会发生+1移码事件。在此我们表明，trpR从0框架到+1框架的转变是通过绕过trpR+1-lacZ mRNA的一段55个核苷酸长的片段实现的。这种绕过事件不是翻译前发生的，可能发生在翻译过程中。需要两个相邻元件：trpR的特定序列，其前面必须有一个比10个可翻译密码子更长的非特异性5'末端。trpR-lacZ绕过的独特之处在于，55个核苷酸长的区域必须在0框架中翻译，才能实现向+1框架的绕过。讨论了翻译绕过这一基因表达新发现机制，并提出了翻译内含子可能存在的观点。
