Advanced

Studies on mRNA turnover in bacteria

Persson, Martin LU (2000)
Abstract (Swedish)
Popular Abstract in Swedish

Genetisk information lagras i DNA, som är en mycket stabil molekyl. I våra celler finns samma gener i alla celler. Det är därför av yttersta vikt att uttrycket av generna kan regleras olika i olika vävnader. Bakterier, som är encelliga organismer, måste för att kunna överleva noga kontrollera uttrycket av olika gener beroende på växlingar i omgivningen. Jag har studerat regleringen av två gener i Bacillus subtilis, som är en ofarlig bakterie som finns i hö och jord. Den ena genen (glpD) kodar för ett protein, som behövs för att bakterien skall kunna växa på glycerol, och proteinet skall därför bara produceras när glycerol är den bästa tillgängliga kol- och energikällan. Den andra genen (aprE)... (More)
Popular Abstract in Swedish

Genetisk information lagras i DNA, som är en mycket stabil molekyl. I våra celler finns samma gener i alla celler. Det är därför av yttersta vikt att uttrycket av generna kan regleras olika i olika vävnader. Bakterier, som är encelliga organismer, måste för att kunna överleva noga kontrollera uttrycket av olika gener beroende på växlingar i omgivningen. Jag har studerat regleringen av två gener i Bacillus subtilis, som är en ofarlig bakterie som finns i hö och jord. Den ena genen (glpD) kodar för ett protein, som behövs för att bakterien skall kunna växa på glycerol, och proteinet skall därför bara produceras när glycerol är den bästa tillgängliga kol- och energikällan. Den andra genen (aprE) kodar för ett protein, som används för att bryta ner proteiner utanför bakterien och produceras bara när bakteriens tillväxt avstannar på grund av näringsbrist. Det finns ett mycket stort industriellt intresse för det sistnämnda proteinet, som ingår i bland annat moderna tvättmedel. En faktor som är av stor betydelse vid genreglering är hur länge den RNA kopia som görs av genen, den så kallade budbärar-RNA (mRNA)- molekylen, är funktionell. mRNA fungerar som mall för proteinsyntesen och ju längre det är funktionellt desto mer protein kan bakterien producera. I bakterier varierar livslängden för olika mRNA från 30 sekunder upp till en timme. Mitt arbete har visat att Bacillus subtilis och en tarmbakterie, Escherichia coli, bryter ner glpD mRNA på olika sätt. Vi har också visat att ett protein, som stabiliserar glpD mRNA i B. subtilis binder till en särskild del av detta mRNA. Vidare presenteras resultat som visar att de strukturer och sekvenser som bestämmer livslängden av såväl glpD som aprE mRNA ligger i den del av molekylen som syntetiseras först, den så kallade 5' regionen. (Less)
Abstract
Genetic information, which is stored in DNA, is transferred to messenger RNA (mRNA) in a process called transcription. mRNAs are then translated by ribosomes into proteins which, with some important exceptions, catalyze chemical reactions in cells. Since cells must be able to adapt to changes in the environment, mRNAs must be unstable. The present investigation concerns mRNA degradation mainly in Bacillus subtilis, which is the model organism for Gram-positive bacteria. Comparative studies have also been performed in the Gram-negative Escherichia coli which is the best characterized bacterium concerning mRNA degradation. I have studied expression of the glpD gene, encoding glycerol-3-phosphate dehydrogenase, which is necessary for growth... (More)
Genetic information, which is stored in DNA, is transferred to messenger RNA (mRNA) in a process called transcription. mRNAs are then translated by ribosomes into proteins which, with some important exceptions, catalyze chemical reactions in cells. Since cells must be able to adapt to changes in the environment, mRNAs must be unstable. The present investigation concerns mRNA degradation mainly in Bacillus subtilis, which is the model organism for Gram-positive bacteria. Comparative studies have also been performed in the Gram-negative Escherichia coli which is the best characterized bacterium concerning mRNA degradation. I have studied expression of the glpD gene, encoding glycerol-3-phosphate dehydrogenase, which is necessary for growth of B. subtilis on glycerol as the sole carbon and energy source. Previous studies have shown that expression of this gene is controlled by a protein, GlpP, which functions both as an antiterminator of transcription and an mRNA stabilizing protein in B. subtilis. The present investigation shows that GlpP binds to glpD mRNA both in vivo and in vitro. In E. coli, GlpP functions as an antiterminator protein but it does not stabilize glpD mRNA. The endoribonucleolytic cleavage pattern of glpD mRNA also differs between the two organisms and the major, RNase III-dependent, processing site found in E. coli is hardly detectable in B. subtilis. Furthermore, the secondary structure of the untranslated leader region of glpD mRNA has been determined both in vivo and in vitro. Based on these findings, a model for GlpP-mediated antitermination and mRNA stabilization is proposed. Studies have also been performed on the expression of the B. subtilis aprE gene, which encodes the excreted protease subtilisin. The results show that the extreme aprE mRNA stability is determined by the 5' region and is independent of growth phase. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof von Gabain, Alexander, Institute of Microbiology and Genetics, Vienna, Austria
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Microbiology, aprE, GlpP, glpD, mRNA secondary structure, Bacillus subtilis, mRNA stability, bacteriology, virology, mycology, Mikrobiologi, bakteriologi, virologi, mykologi
pages
88 pages
publisher
Biology building
defense location
Lecture hall of Plant Physiology, Sölvegatan 35
defense date
2000-12-01 10:00
external identifiers
  • Other:ISRN: LUNBDS/NBNB-1038/1-45 (2000)
ISBN
91-628-4518-7
language
English
LU publication?
yes
id
36081a57-91ce-4a05-8bd8-73b2b9e5faca (old id 41071)
date added to LUP
2007-07-31 14:54:25
date last changed
2016-09-19 08:45:08
@misc{36081a57-91ce-4a05-8bd8-73b2b9e5faca,
  abstract     = {Genetic information, which is stored in DNA, is transferred to messenger RNA (mRNA) in a process called transcription. mRNAs are then translated by ribosomes into proteins which, with some important exceptions, catalyze chemical reactions in cells. Since cells must be able to adapt to changes in the environment, mRNAs must be unstable. The present investigation concerns mRNA degradation mainly in Bacillus subtilis, which is the model organism for Gram-positive bacteria. Comparative studies have also been performed in the Gram-negative Escherichia coli which is the best characterized bacterium concerning mRNA degradation. I have studied expression of the glpD gene, encoding glycerol-3-phosphate dehydrogenase, which is necessary for growth of B. subtilis on glycerol as the sole carbon and energy source. Previous studies have shown that expression of this gene is controlled by a protein, GlpP, which functions both as an antiterminator of transcription and an mRNA stabilizing protein in B. subtilis. The present investigation shows that GlpP binds to glpD mRNA both in vivo and in vitro. In E. coli, GlpP functions as an antiterminator protein but it does not stabilize glpD mRNA. The endoribonucleolytic cleavage pattern of glpD mRNA also differs between the two organisms and the major, RNase III-dependent, processing site found in E. coli is hardly detectable in B. subtilis. Furthermore, the secondary structure of the untranslated leader region of glpD mRNA has been determined both in vivo and in vitro. Based on these findings, a model for GlpP-mediated antitermination and mRNA stabilization is proposed. Studies have also been performed on the expression of the B. subtilis aprE gene, which encodes the excreted protease subtilisin. The results show that the extreme aprE mRNA stability is determined by the 5' region and is independent of growth phase.},
  author       = {Persson, Martin},
  isbn         = {91-628-4518-7},
  keyword      = {Microbiology,aprE,GlpP,glpD,mRNA secondary structure,Bacillus subtilis,mRNA stability,bacteriology,virology,mycology,Mikrobiologi,bakteriologi,virologi,mykologi},
  language     = {eng},
  pages        = {88},
  publisher    = {ARRAY(0xa725028)},
  title        = {Studies on mRNA turnover in bacteria},
  year         = {2000},
}