Year: 2012
Type: dissertation
Abstract: In prokaryotes, transcription and translation are coupled and as a result, the beginning of the \nmessenger RNA is translated by the ribosome while the 3' end is still synthesized. How \nexactly this occurs is still not clear. One possibility is that RNA polymerase and the \nribosomes may be in physical contact with each other at some stage during gene expression \nor RNA polymerase has a binding site in the ribosomes. Mutational analysis is one method to \nexplore how coordination between these two moieties occurs in bacteria. \nAn Escherichia coli strain with all seven chromosomal ribosomal RNA operons deleted, \nreplaced by a single rrnB plasmid-borne operon, was used to isolate ribosomal RNA mutants \nwith increased rifampicin resistance, two of which were studied further. The altered rrnB \noperon in pGM1 was obtained by spontaneous whilst in pGM2 by EMS mutagenesis. The \nmutated rrnB operon in pGM1 conferred resistance to 25μg/ml of rifampicin while in pGM2 \nresistance of 30μg/ml was observed. A base substitution of T to A at position 355 of the 23S \nrRNA was detected in pGM1and no nucleotide change was detected in pGM2. The successful \nisolation of ribosomal RNA mutants with rifampicin resistance is consistent with the \nhypothesis of interaction between the RNA polymerase and the ribosomes and suggests the \npart of this interaction is with the large ribosomal subunit.
Author: Rulane Glenda Macheke
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funder: National Research Foundation
OpenAlex ID: W2105891917