TRANSCRIPTION TERMINATES AT LAMBDA-TR1 IN 3 CLUSTERS
TRANSCRIPTION TERMINATES AT LAMBDA-TR1 IN 3 CLUSTERS
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DOI：
10.1073/pnas.79.20.6171
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
WU, R
中科院分区：
文献类型：
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作者：
LAU, LF;ROBERTS, JW;WU, R
噬菌体右操纵子的转录。在。rho出现时终止。在一个被称为tRl的区域，位于裂解抑制基因的下游。核酸酶Sl图谱显示转录终止于。lambda。TRL在体外发生的长度为60个核苷酸。转录本的末端聚集在3个不同的区域，称为终止位点I、II和III。L因子抑制位点I的终止，而位点II和III的终止不受L因子的影响。这些位点对。rho的敏感性。因子的顺序为III > II > I。cin- lnc -l突变在II位点终止，但在I和III位点不终止；这一结果可能解释了这些突变无法减轻噬菌体生长对N功能的需求。虽然在3个终止位点上游的RNA转录本中可以找到可能的茎环结构，但这些茎环结构的强度与其各自位点的终止效率之间不存在一致的相关性。
Transcription of the rightward operon of bacteriophage .lambda. terminates in the presence of .rho. factor at a region known as tRl, located downstream of the structural gene for the lytic repressor cro. Nuclease Sl mapping demonstrated that transcription termination at .lambda.trl occurs in vitro over a stretch of 60 nucleotides. End points of transcripts are clustered in 3 distinct regions, referred to as termination sites I, II and III. Termination at site I is inhibited by L factor, whereas termination at sites II and III is not affected by L factor. The sensitivities of these sites to .rho. factor are in the order III > II > I. The cin-lcnc-l mutations abolish termination at site II but not at sites I and III; this result may explain the failure of these mutations to alleviate the phage requirement for N function for growth. Although possible stem-and-loop structures in the RNA transcript immediately upstream of each of the 3 termination sites can be found, no consistent correlation exists between the strengths of these stem-and-loop structures and the termination efficiencies of their respective sites.