Chen C Y, Galluppi G R, Richardson J P
Cell. 1986 Sep 26;46(7):1023-8. doi: 10.1016/0092-8674(86)90701-4.
To determine whether E. coli rho protein mediates termination of transcription by interacting with specific segments of the nascent transcript, DNA oligonucleotides were used to sequester segments of phage lambda cro mRNA in hybrid helices. Formation of hybrids was demonstrated with RNAase H assays. Oligonucleotides complementary to either of two distinct, single-stranded sequences near the 3' end inhibited rho action at tR1, while oligonucleotides complementary to the sequence between those segments or to more 5' segments did not. The inhibitory oligonucleotides did not affect the elongation of cro mRNA or rho action on other transcripts. The results indicate that termination of transcription at tR1 is dependent upon contact of rho factor with specific, single-stranded domains near the 3' end of cro mRNA.
为了确定大肠杆菌rho蛋白是否通过与新生转录本的特定片段相互作用来介导转录终止，使用DNA寡核苷酸在杂交螺旋中隔离噬菌体λ cro mRNA的片段。通过RNA酶H测定法证明了杂交体的形成。与3'端附近两个不同的单链序列之一互补的寡核苷酸在tR1处抑制rho作用，而与这些片段之间的序列或更5'端片段互补的寡核苷酸则没有。抑制性寡核苷酸不影响cro mRNA的延伸或rho对其他转录本的作用。结果表明，tR1处的转录终止取决于rho因子与cro mRNA 3'端附近特定的单链结构域的接触。
