Role of the non-template strand of the elongation bubble in intrinsic transcription termination.
Intrinsic transcription terminators of Escherichia coli and other bacteria, consisting primarily of an RNA hairpin preceding a terminal uridine-rich RNA segment, suffice to dissociate the otherwise stable elongation complex of core RNA polymerase. The essential functions of the hairpin and U-rich segments have been established, although the precise mechanism of termination is unknown. We identify another element of the terminator, namely the non-template DNA strand in the region of the terminal transcription bubble. Failure of the terminal bubble to rewind through complementary base-pairing strongly reduces the efficiency of terminator function, suggesting that the natural pathway of termination consists of coupled rewinding of the DNA template and unwinding of the RNA/DNA hybrid at the site of release.
Ryder
Andrew M
AM
Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA.
Roberts
Jeffrey W
JW
D001483:Base Sequence; D004926:Escherichia coli / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D014158:Transcription, Genetic / Q000502:physiology*