An Escherichia coli gene (yaeO) suppresses temperature-sensitive mutations in essential genes by modulating Rho-dependent transcription termination.
An extragenic multicopy suppressor of the cell division inhibition caused by a MalE-MinE fusion protein in Escherichia coli has been mapped and identified as yaeO, one of the two short open reading frames (ORFs) of an operon located at 4.6 min. Overexpressed yaeO also suppressed some temperature-sensitive mutations in division genes ftsA and ftsQ, in chaperone gene groEL and in co-chaperone gene grpE. Gene yaeO, whose expression is regulated by growth rate, codes for a 9 kDa acidic protein with no obvious resemblance to other proteins. Transcription termination protein Rho co-purified with a histidine-tagged derivative of YaeO protein on Ni2+-NTA agarose columns in a manner that suggested direct YaeO-Rho interaction. In vivo, yaeO expression reduced termination at rho-dependent bacteriophage terminator tL1 and at the terminator of autogenously regulated gene rho. The suppression of temperature-sensitive phenotypes was a consequence of anti-termination, as it could be mimicked by a Prho::Tn10 mutation that reduces the expression and activity of gene rho. Our data indicate that the suppression is not caused by overexpression of the mutated genes, but presumably by indirect stabilization of the mutated proteins.
Laboratoire de Microbiologie et de Génétique Moléculaire du CNRS, Toulouse, France.
S
S
Pichoff
L
L
Alibaud
A
A
Guédant
M P
MP
Castanié
J P
JP
Bouché
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D018797:Cell Cycle Proteins; D002874:Chromosome Mapping; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D009876:Operon; D033902:Periplasmic Binding Proteins; D012234:Rho Factor; D013696:Temperature; D014158:Transcription, Genetic
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C065103:FtsA protein, Bacteria; C489310:FtsA protein, E coli; C071525:FtsZ protein, Bacteria; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; C093548:MinE protein, E coli; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D012234:Rho Factor; C461599:maltose transport system, E coli