Previous Article | Next Article ![]()
J. Bacteriol., 10 1995, 5485-5494, Vol 177, No. 19
M Osteras, J Stanley and TM Finan
Analysis of the DNA regions upstream of the phosphoenolpyruvate
carboxykinase gene (pckA) in Rhizobium meliloti and Rhizobium sp. strain
NGR234 identified an open reading frame which was highly homologous to the
Agrobacterium tumefaciens chromosomal virulence gene product ChvI. A second
gene product, 500 bp downstream of the chvI-like gene in R. meliloti, was
homologous to the A. tumefaciens ChvG protein. The homology between the R.
meliloti and A. tumefaciens genes was confirmed, because the R. meliloti
chvI and chvG genes complemented A. tumefaciens chvI and chvG mutants for
growth on complex media. We were unable to construct chvI or chvG insertion
mutants of R. meliloti, whereas mutants carrying insertions outside of
these genes were readily obtained. A 108-bp repeat element characterized by
two large palindromes was identified in the chvI and chvG intergenic
regions of both Rhizobium species. This element was duplicated in Rhizobium
sp. strain NGR234. Another structurally similar element with a size of 109
bp was present in R. meliloti but not in Rhizobium sp. strain NGR234. These
elements were named rhizobium-specific intergenic mosaic elements (RIMEs),
because their distribution seems to be limited to members of the family
Rhizobiaceae. A homology search in GenBank detected six more copies of the
first element (RIME1), all in Rhizobium species, and three extra copies of
the second element (RIME2), only in R. meliloti. Southern blot analysis
with a probe specific to RIME1 showed the presence of several copies of the
element in the genome of R. meliloti, Rhizobium sp. strain NGR234,
Rhizobium leguminosarum, and Agrobacterium rhizogenes, but none was present
in A. tumefaciens and Bradyrhizobium japonicum.
Copyright © 1995, American Society for Microbiology
Identification of Rhizobium-specific intergenic mosaic elements within an essential two-component regulatory system of Rhizobium species
Department of Biology, McMaster University, Hamilton, Ontario, Canada.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |