Protection of antiterminator RNA by the transcript elongation complex.
Nascent transcripts encoded by the putL and putR sites of phage HK022 bind the transcript elongation complex and suppress termination at downstream transcription terminators. We report here that the chemical stability of putL RNA is considerably greater than that of the typical Escherichia coli message because the elongation complex protects this RNA from degradation. When binding to the elongation complex was prevented by mutation of either putL or RNA polymerase, RNA stability decreased more than 50-fold. The functional modification conferred by putL RNA on the elongation complex is also long-lived: the efficiency of terminator suppression remained high for at least 10 kb from the putL site. We find that RNase III rapidly and efficiently cleaved the transcript just downstream of the putL sequences, but such cleavage changed neither the stability of putL RNA nor the efficiency of antitermination. These results argue that the continuity of the RNA that connects put sequences to the growing point is not required for persistence of the antiterminating modification in vivo.
Sloan
Sieghild
S
Section on Microbial Genetics, Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, Bethesda, MD 20892-2785, USA.
Rutkai
Edit
E
King
Rodney A
RA
Velikodvorskaya
Tatyana
T
Weisberg
Robert A
RA
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D025523:Bacteriophage HK022 / Q000235:genetics*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D038621:Regulatory Sequences, Ribonucleic Acid; D013728:Terminator Regions, Genetic; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; C096745:PutR protein, Bacteria; D012367:RNA, Viral; D038621:Regulatory Sequences, Ribonucleic Acid; D015534:Trans-Activators; D035602:Transcriptional Elongation Factors