Lopes J M, Lawther R P
Nucleic Acids Res. 1986 Mar 25;14(6):2779-98. doi: 10.1093/nar/14.6.2779.
It was previously determined that the distal portion of the ilvGMEDA operon was expressed despite the insertion of transposons into ilvG and ilvE. This observation suggested the existence of internal promoters upstream of ilvE (pE) and ilvD (pD). The internal promoter pE, responsible for part of ilvEDA expression, has been analyzed both in vivo and in vitro. Our results indicate that: pE exists in both E. coli K-12 and S. typhimurium; pE is located in the distal end of the ilvM coding sequence; the pE sequence is highly conserved in the two bacteria; the amino acid sequence of the ilvM gene product is 93% homologous between the two bacteria; transcription from pE can be demonstrated both in vivo and in vitro; the efficiency of pE is essentially equivalent in the two bacteria.
先前已确定，尽管转座子插入了ilvG和ilvE，但ilvGMEDA操纵子的远端部分仍有表达。这一观察结果表明，在ilvE（pE）和ilvD（pD）上游存在内部启动子。负责ilvEDA部分表达的内部启动子pE已在体内和体外进行了分析。我们的结果表明：pE存在于大肠杆菌K-12和鼠伤寒沙门氏菌中；pE位于ilvM编码序列的远端；pE序列在这两种细菌中高度保守；ilvM基因产物的氨基酸序列在这两种细菌之间有93%的同源性；pE的转录在体内和体外均可得到证实；pE在这两种细菌中的效率基本相当。
