RNA polymerase transcription rate of stable RNA

Value 85 nt/sec Range: Table - link nt/sec
Organism Bacteria Escherichia coli
Reference Bremer, H., Dennis, P. P. (1996) Modulation of chemical composition and other parameters of the cell by growth rate. Neidhardt, et al. eds. Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd ed. chapter 97 Table 3
Primary Source [99] Molin, S. 1976. Ribosomal RNA chain elongation rates in Escherichia coli, p. 333-339. In N. Kjeldgaard and 0. Maaloe (ed.), Alfred Benzon Symposium, IX. Academic Press, Inc., New York. [120] Ryals, J., R. Little, and H. Bremer. 1982. Temperature dependence of RNA synthesis parameters in Escherichia coli. J. Bacteriol. 151: 879–887. [124] Shen, V., and H. Bremer. 1977. Rate of ribosomal ribonucleic acid chain elongation in Escherichia coli B/r during chloramphenicol treatment. J. Bacteriol. 130: 1109–1116.PubMed ID6178724, 324975
Method (Footnote 'f' beneath table:) "The stable RNA (or rRNA) chain growth rate was determined from 5S rRNA or tRNA labeling after rifampin addition (primary sources 99, 120, 124)." (Primary source [99] pp.333-4:) "The analysis is based on 2 important characteristics of the 5S ribosomal RNA: 1) the molecule is very small (120 nts(Rosset & Monier 1963)), presumably much smaller than any completed mRNA molecule and (2) the genes coding for 5S rRNA are situated at the promoter distal ends of the transcriptional units for the three ribosomal RNA species (Pato & von Meyenburg 1970, Doolittle & Pace 1970, Steitz this volume, Lindahl et al. this volume). Addition of rifampicin,which is known to inhibit initiation of transcription specifically (see e.g. Pato & von Meyenburg 1970), together with a labeled precursor should make it possible to measure the time needed to transcribe the part of the operon preceding the 5S RNA gene by following the kinetics of accumulation of label in 5S RNA. The specific activity of this RNA molecule will rise until the last RNA polymerase molecule (which had initiated transcription just before the rifampicin addition) has reached the 5S RNA cistron whereafter it will remain constant."
Comments Stable RNA refers to rRNA, tRNA and their spacers. Experiment performed at three different growth rates and media: 1)d-ribose (µ=0.8), 2) glucose (µ=1.2), 3)glucose+casamino acid (µ=2.3) At the three growth rates the specific activity reached a constant level at the same time (ca. 75 sec after addition of rifampicin and 3H adenine). Determination of the actual RNA chain growth rate depends on the number of bases that are between the promoter of the rRNA transcriptional unit and the 5S rRNA cistron. This number is between 4600 which is the sum of bases in 16S and 23S RNA and 6000, the approximate size of the 30S rRNA precursor. For the transcription time observed of 75 seconds the chain growth rate of rRNA is thus calculated to be in the range of 60-80 nts/sec. Approximately 80 nt/sec according to Benno Muller-hill, 1996, The Lac Operon: A Short History Of A Genetic Paradigm, Publisher: Walter de Gruyter. Berlin. New York. Part 3.2 p.134. For rRNA transcription rate of 42 nts/sec as obsereved by electron microscopy see BNID 101904 and comments section therein. See BNID 100662
Entered by Ron Milo, Paul Jorgensen, Mike Springer
ID 100060