Abstract
The genes coding for the beta (rpoB) and beta' (rpoC) subunits of RNA polymerase are fused in the gastric pathogen Helicobacter pylori but separate in other taxonomic groups. To better understand how the unique fused structure evolved, we determined DNA sequences at and around the rpoB-rpoC junction in 10 gastric and nongastric species of Helicobacter and in members of the related genera Wolinella, Arcobacter, Sulfurospirillum, and Campylobacter. We found the fusion to be specific to Helicobacter and Wolinella genera; rpoB and rpoC overlap in the other genera. The fusion may have arisen by a frameshift mutation at the site of rpoB and rpoC overlap. Loss of good Shine-Dalgarno sequences might then have fixed the fusion in the Helicobacteraceae, even if fusion itself did not confer a selective advantage.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Campylobacter / classification
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Campylobacter / genetics*
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Campylobacter / isolation & purification
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DNA-Directed RNA Polymerases / chemistry
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DNA-Directed RNA Polymerases / genetics*
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Evolution, Molecular*
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Gastric Mucosa / microbiology
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Genes, Bacterial
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Genes, Overlapping
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Gram-Negative Bacteria / genetics
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Helicobacter / classification
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Helicobacter / genetics*
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Helicobacter / isolation & purification
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Humans
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Molecular Sequence Data
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Phylogeny*
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Sequence Alignment
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Sequence Homology, Amino Acid
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Sequence Homology, Nucleic Acid
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Wolinella / genetics
Substances
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beta' subunit of RNA polymerase
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DNA-Directed RNA Polymerases
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RNA polymerase beta subunit
Associated data
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GENBANK/AF136503
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GENBANK/AF136504
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GENBANK/AF136505
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GENBANK/AF136506
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GENBANK/AF136507
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GENBANK/AF136508
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GENBANK/AF136509
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GENBANK/AF136510
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GENBANK/AF136511
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GENBANK/AF136512
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GENBANK/AF136513
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GENBANK/AF136514
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GENBANK/AF136515
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GENBANK/AF136516
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GENBANK/AF136517
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GENBANK/AF136518