Relative rate of rRNA synthesis compared to total RNA synthesis on Orotate medium

Value 0.16 Unitless
Organism Bacteria Escherichia coli
Reference Vogel U, Pedersen S, Jensen KF. An unusual correlation between ppGpp pool size and rate of ribosome synthesis during partial pyrimidine starvation of Escherichia coli. J Bacteriol. 1991 Feb173(3):1168-74 Table - link PubMed ID1704003
Method Escherichia coli was exposed to partial pyrimidine starvation by feeding a pyrBI strain orotate as the only pyrimidine source. Bacteria were prelabeled with 32p of a low specific activity while growing on either uracil (20 ,ug/ml) or orotate (50 ,ug/ml). Then pulses of [3H]adenine were given, and the RNA was extracted at different intervals. The ratio of 3H to 32P was determined for both total RNA and rRNA (defined as RNA hybridizing to the rrnX operon on X DNA [ref 10 in article]). 1.5 min pulses
Comments The limiting value of the composite ratio (3H/32P)rRNA/ 3H/32P)total RNA at pulse times approaching time zero, is a measure of the fraction of transcribing RNA polymerases engaged in formation of rRNA chains, and as seen from Table link, this fraction was lower in cells grown in orotate than in those grown in uracil. See BNID 104808
Entered by Uri M
ID 104807