Document Detail

Opposite consequences of two transcription pauses caused by an intrinsic terminator oligo(U): antitermination versus termination by bacteriophage T7 RNA polymerase.
MedLine Citation:
PMID:  21398520     Owner:  NLM     Status:  MEDLINE    
The RNA oligo(U) sequence, along with an immediately preceding RNA hairpin structure, is an essential cis-acting element for bacterial class I intrinsic termination. This sequence not only causes a pause in transcription during the beginning of the termination process but also facilitates transcript release at the end of the process. In this study, the oligo(U) sequence of the bacteriophage T7 intrinsic terminator Tφ, rather than the hairpin structure, induced pauses of phage T7 RNA polymerase not only at the termination site, triggering a termination process, but also 3 bp upstream, exerting an antitermination effect. The upstream pause presumably allowed RNA to form a thermodynamically more stable secondary structure rather than a terminator hairpin and to persist because the 5'-half of the terminator hairpin-forming sequence could be sequestered by a farther upstream sequence via sequence-specific hybridization, prohibiting formation of the terminator hairpin and termination. The putative antiterminator RNA structure lacked several base pairs essential for termination when probed using RNases A, T1, and V1. When the antiterminator was destabilized by incorporation of IMP into nascent RNA at G residue positions, antitermination was abolished. Furthermore, antitermination strength increased with more stable antiterminator secondary structures and longer pauses. Thus, the oligo(U)-mediated pause prior to the termination site can exert a cis-acting antitermination activity on intrinsic terminator Tφ, and the termination efficiency depends primarily on the termination-interfering pause that precedes the termination-facilitating pause at the termination site.
Sooncheol Lee; Changwon Kang
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-03-11
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  286     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-05-02     Completed Date:  2011-07-01     Revised Date:  2013-06-30    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  15738-46     Citation Subset:  IM    
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea.
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MeSH Terms
Bacteriophage T7 / enzymology*
DNA-Directed RNA Polymerases / chemistry,  metabolism*
Nucleic Acid Conformation
Poly U / chemistry,  metabolism*
RNA, Viral / biosynthesis*,  chemistry
Transcription, Genetic / physiology*
Viral Proteins / chemistry,  metabolism*
Reg. No./Substance:
0/RNA, Viral; 0/Viral Proteins; 27416-86-0/Poly U; EC 2.7.7.-/bacteriophage T7 RNA polymerase; EC RNA Polymerases

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