Kim S, Lee Y
Department of Chemistry, Korea Advanced Institute of Science and Technology, Taejon, Korea.
Mol Cells. 1997 Feb 28;7(1):110-4.
The region for intrinsic transcription termination of the Escherichia coli rnpB gene coding for M1 RNA is repeated three times. Each region encodes an RNA-terminator hairpin and U-rich 3' tail. Most transcription is terminated at the first terminator (T1), but a complete termination requires the second terminator (T2) and the third (T3). A deletion experiment, where deletions were extended from T3 into T1, was carried out to determine parameters affecting in vivo transcription termination at T1. The deletion of T3, T2 or the downstream sequences up to near the termination site of T1 showed little or no significant effect on transcription termination at T1. When the base corresponding to the acute termination position of T1 was included in the deletion, termination efficiency slightly decreased. For T1 bearing the deletion of the region encoding the RNA-terminator hairpin and U-rich 3' tail, termination was completely abolished. When T1 contained only the region encoding the RNA-termination hairpin without the U-rich 3' tail, termination still occurred even though the efficiency was low. Characteristics of rnpB termination were discussed with these results.
编码M1 RNA的大肠杆菌rnpB基因的内在转录终止区域重复了三次。每个区域编码一个RNA终止发夹和富含U的3'尾巴。大多数转录在第一个终止子（T1）处终止，但完全终止需要第二个终止子（T2）和第三个终止子（T3）。进行了一项缺失实验，缺失从T3延伸到T1，以确定影响T1处体内转录终止的参数。删除T3、T2或直至T1终止位点附近的下游序列对T1处的转录终止几乎没有或没有显著影响。当与T1的急性终止位置对应的碱基包含在缺失中时，终止效率略有下降。对于缺失了编码RNA终止发夹和富含U的3'尾巴区域的T1，终止完全被消除。当T1仅包含编码RNA终止发夹的区域而没有富含U的3'尾巴时，尽管效率很低，但终止仍然发生。根据这些结果讨论了rnpB终止的特征。
