In E. coli, the mRNA of an operon for two synthesis enzymes has a leader containing the sequence near the site where translation of the first protein starts.

• 在大肠杆菌中，两个维生素B1合成酵素的基因所共有的操纵子，转录出来的mRNA在靠近蛋白质转译起点处，有一段先导序列。