Baum E Z, Buttner M J, Lin L S, Rothstein D M
Medical Research Division, Lederle Laboratories, American Cyanamid Company, Pearl River, New York 10965.
J Bacteriol. 1989 Dec;171(12):6503-10. doi: 10.1128/jb.171.12.6503-6510.1989.
We demonstrated previously that the 0.4-kilobase DNA fragment from Micromonospora echinospora contains multiple tandem promoters, P1a, P1b, P1c, and P2, which are also functional when cloned into Streptomyces lividans. We now show by in vitro transcription with Streptomyces RNA polymerase that each of these promoters is an authentic initiation site, rather than a processing site for transcripts which initiate further upstream. The DNA sequence requirements for the closely spaced promoters P1a, P1b, and P1c, which are coordinately induced during stationary phase in M. echinospora, were examined by deletional analysis in S. lividans. The P1a and P1b promoters were functional despite deletion of native sequences 5 and 17 base pairs upstream of each initiation site, respectively. Thus, P1a and P1b had greatly reduced upstream DNA sequence requirements compared with typical procaryotic promoters. In contrast, transcription from promoter P1c was significantly decreased when native sequences 34 base pairs upstream were replaced.
我们之前证明，来自棘孢小单孢菌的0.4千碱基DNA片段含有多个串联启动子，即P1a、P1b、P1c和P2，将其克隆到变铅青链霉菌中时也具有功能。我们现在通过用链霉菌RNA聚合酶进行体外转录表明，这些启动子中的每一个都是一个真正的起始位点，而不是在更上游起始的转录本的加工位点。通过在变铅青链霉菌中进行缺失分析，研究了在棘孢小单孢菌稳定期协同诱导的紧密间隔启动子P1a、P1b和P1c的DNA序列要求。尽管分别缺失了每个起始位点上游5个和17个碱基对的天然序列，P1a和P1b启动子仍具有功能。因此，与典型的原核启动子相比，P1a和P1b对上游DNA序列的要求大大降低。相比之下，当上游34个碱基对的天然序列被替换时，来自启动子P1c的转录显著减少。
