Range: ±2 nucleotides/sec
||Bacteria Escherichia coli
||Gotta SL, Miller OL Jr, French SL. rRNA transcription rate in Escherichia coli. 1991. J Bacteriol. 173(20) pp.6647-9. abstract, p.6647 right column 2nd paragraph, p.6649 caption to fig.2 & left column top paragraphPubMed ID1717439
||P.6647 left column 2nd paragraph: "Log-phase cultures of E. coli W3110 grown at 37°C in LB medium (ref 16) (µ= 2.4 doublings per h) were exposed to rifampin (200µg/ml) for 0, 30, 40, or 70 s and then prepared for electron microscopy by the Miller chromatin-spreading technique (refs 10, 12). Bacterial cell contents were dispersed in pH 9 water without EDTA. Samples were viewed in a JEOL 100C transmission electron microscope. Measurements from micrographs were made with a Numonics 2200 digitizing tablet and Jandel SigmaScan software." P.6647 left column bottom paragraph: "To determine the rate of rRNA chain elongation in E. coli, initiation of transcription was inhibited with rifampin and the progression of previously initiated RNA polymerases was observed along the rRNA operons. As the time following rifampin addition increased, the length of the operons densely packed with RNA polymerases decreased in a 5'-to-3' direction (Fig.1)."
||P.6647 right column 2nd paragraph: "Linear regression analysis of the length of rDNA template densely packed with RNA polymerases versus time following rifampin addition (Fig. 2) yielded a transcription elongation
rate of 42 nucleotides per s (standard error of slope = ±2 nucleotides per s, r^2 = 0.82). Elimination of the 0-s data
from regression analysis yielded a transcription elongation rate of 43±3 nucleotides per s (r^2 = 0.66), indicating that inhibition of transcription initiation occurred rapidly." P.6648 left column bottom paragraph: "Previous measurements of rRNA chain elongation rates ranging from 12.5 to 105 nucleotides per s have been indirect." P.6648 right column: "Recent estimates of transcription rates may be too high because of the mistaken assumption that most tRNAs cotranscribed with rRNA are located at the distal ends of rRNA operons (ref 22), when in fact only three of the seven rRNA operons in E. coli have tRNA genes downstream of their 23S cistrons. A more accurate rate would have been reported by Bremer and colleagues (refs 2, 22, 23) if measurements had been based on individual tRNA species at known distances from their respective promoters." Transcription rate is believed to vary with growth rate (see Vogel and Jensen, 1994 for more information, BNID 101905). See BNID 100060 for stable RNA transcription rate of 85 nts/sec. See BNID 100662