Roberts A N, Hudson G S, Brenner S
Gene. 1985;35(3):259-70. doi: 10.1016/0378-1119(85)90004-6.
A gene (ermA) coding for a presumed erythromycin-resistance (ErR) determinant from an Er-producing Arthrobacter sp. strain (NRRLB3381) was isolated from a gene bank in phage vector lambda 2001 by probing with a Streptomyces ErR gene. Strongly hybridizing fragments were subcloned and the appropriate segments sequenced. The ermA gene is 76 mol% G + C in content and specifies a protein of 340 aa with an Mr of 37454. S1 nuclease mapping and primer extension identified the putative promoter, which resembles the consensus sequence of Escherichia coli promoters particularly in the -10 region. A potential ribosome-binding site (RBS) (AGGAG) was also located. Unexpectedly, the majority of in vivo ermA transcripts detected were only 245 nt long, suggesting that expression of ErR may be regulated post-transcriptionally. Substantial homology is observed between the predicted aa sequences of the ermA-coded protein and the products of three other ErR determinants, from organisms that do not produce Er.
从一株产红霉素的节杆菌属菌株（NRRLB3381）中分离出一个编码假定红霉素抗性（ErR）决定簇的基因（ermA），该基因库存在噬菌体载体λ2001中，通过用链霉菌属ErR基因进行探针杂交筛选获得。将强杂交片段亚克隆，并对合适的片段进行测序。ermA基因的G + C含量为76 mol%，编码一个由340个氨基酸组成、Mr为37454的蛋白质。S1核酸酶图谱分析和引物延伸确定了推定的启动子，该启动子与大肠杆菌启动子的共有序列相似，尤其是在 -10区域。还定位了一个潜在的核糖体结合位点（RBS）（AGGAG）。出乎意料的是，检测到的大多数体内ermA转录本长度仅为245 nt，这表明ErR的表达可能在转录后受到调控。在ermA编码蛋白的预测氨基酸序列与另外三个来自不产Er的生物体的ErR决定簇产物之间观察到了高度同源性。
