期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1993
卷号：90
期号：3
页码：970-974
DOI：10.1073/pnas.90.3.970
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Using an in vitro transcription assay, we have successfully demonstrated read through of a Rho-dependent terminator by the ribosomal RNA antitermination system. The assay used a DNA template containing a promoter-antiterminator-terminator arrangement, RNA polymerase, termination factor Rho, antitermination factors NusA, NusB, NusE, and NusG, and a cellular extract depleted of NusB. Terminator read-through was highly efficient only in the presence of the extract and Nus factors, suggesting that an as yet uncharacterized cellular component is required for ribosomal antitermination. The NusB-depleted extract had no activity in the absence of NusB, confirming an absolute requirement for this protein in ribosomal RNA antitermination. The DNA template requirements were the same as those previously established in vivo; transcription of a wild-type boxA sequence is both necessary and sufficient to promote RNA polymerase modification into a terminator-resistant form.
