Two of the three groEL homologues in Rhizobium leguminosarum are dispensable for normal growth

Rodríguez-Quiñones, Francisco; Maguire, Maria; Wallington, Emma J.; Gould, Phillip S.; Yerko, V. N.; Downie, J. Allan; Lund, Peter A.

doi:10.1007/s00203-005-0768-7

Cited by 43 publications

(42 citation statements)

References 62 publications

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“…Sequence analysis followed by detailed promoter probe assays revealed that the groEL1 operon is regulated by RpoH-and HrcA-dependent mechanisms while groEL2 appears to be solely regulated by RpoH. Expectedly, groEL3 is induced by NifA and moderately repressed by HrcA (Rodriguez-Quinones et al 2005;Gould et al 2007b). These results therefore indicate that the essential chaperonin is expressed at the highest levels and the expression is tightly controlled by RpoH and HrcA.…”

Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

“…Attempts to understand the biological functions of GroEL1 and GroEL2 continued with genetic and biochemical tools. Among the three GroELs, GroEL1 is essential while GroEL2 and GroEL3 are dispensable individually and in combination (Rodriguez-Quinones et al 2005) although double mutants in other rhizobia are lethal as observed in the case of B. japonicum (Fischer et al 1999). The presence of multiple copies of chaperonins immediately suggests differences in the regulation of expression or differences in function.…”

Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

“…Although all the three operons are heat inducible and mediated through the CIRCE elements, differential levels of expression have been demonstrated; the essential chaperonin groEL1 shows the highest induction followed by groEL2 (Rodriguez-Quinones et al 2005). On the other hand, induction of groEL3 is very low following heat shock, but higher levels are observed under anaerobic conditions and in the presence of NifA (Rodriguez-Quinones et al 2005;Yeh et al 2002). Sequence analysis followed by detailed promoter probe assays revealed that the groEL1 operon is regulated by RpoH-and HrcA-dependent mechanisms while groEL2 appears to be solely regulated by RpoH.…”

Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

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Multiple chaperonins in bacteria—novel functions and non-canonical behaviors

Kumar

Mande

Mahajan

2015

Cell Stress and Chaperones

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Chaperonins are a class of molecular chaperones that assemble into a large double ring architecture with each ring constituting seven to nine subunits and enclosing a cavity for substrate encapsulation. The well-studied Escherichia coli chaperonin GroEL binds non-native substrates and encapsulates them in the cavity thereby sequestering the substrates from unfavorable conditions and allowing the substrates to fold. Using this mechanism, GroEL assists folding of about 10-15 % of cellular proteins. Surprisingly, about 30 % of the bacteria express multiple chaperonin genes. The presence of multiple chaperonins raises questions on whether they increase general chaperoning ability in the cell or have developed specific novel cellular roles. Although the latter view is widely supported, evidence for the former is beginning to appear. Some of these chaperonins can functionally replace GroEL in E. coli and are generally indispensable, while others are ineffective and likewise are dispensable. Additionally, moonlighting functions for several chaperonins have been demonstrated, indicating a functional diversity among the chaperonins. Furthermore, proteomic studies have identified diverse substrate pools for multiple chaperonins. We review the current perception on multiple chaperonins and their physiological and functional specificities.

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Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

Section: Multiple Chaperonins In Rhizobium-the Division Of Labor Situmentioning

confidence: 99%

See 1 more Smart Citation

Multiple chaperonins in bacteria—novel functions and non-canonical behaviors

Kumar

Mande

Mahajan

2015

Cell Stress and Chaperones

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“…Nevertheless, some genes for the biosynthesis of thiamin, cobalamin, and NAD are located on the pRL11JI plasmid. Other essential plasmid genes include major heat-shock chaperone genes cpn10/cpn60 (groES/groEL) on pRL12JI, and ribosomal protein S21 on pRL10JI (pSym); however, these genes have chromosomal paralogs so the different copies may be simply functionally redundant [17,85]. pRL12JI similarly to the pRetCFN42f of Rhe carries some genes for flagella biosynthesis and oxidative stress protection [83].…”

Section: Rhizobial Plasmids Structure Gene Content and Impact On Bacmentioning

confidence: 99%

Rhizobial plasmids — replication, structure and biological role

Mazur

Koper

2012

Open Life Sciences

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AbstractSoil bacteria, collectively named rhizobia, can establish mutualistic relationships with legume plants. Rhizobia often have multipartite genome architecture with a chromosome and several extrachromosomal replicons making these bacteria a perfect candidate for plasmid biology studies. Rhizobial plasmids are maintained in the cells using a tightly controlled and uniquely organized replication system. Completion of several rhizobial genome-sequencing projects has changed the view that their genomes are simply composed of the chromosome and cryptic plasmids. The genetic content of plasmids and the presence of some important (or even essential) genes contribute to the capability of environmental adaptation and competitiveness with other bacteria. On the other hand, their mosaic structure results in the plasticity of the genome and demonstrates a complex evolutionary history of plasmids. In this review, a genomic perspective was employed for discussion of several aspects regarding rhizobial plasmids comprising structure, replication, genetic content, and biological role. A special emphasis was placed on current post-genomic knowledge concerning plasmids, which has enriched the view of the entire bacterial genome organization by the discovery of plasmids with a potential chromosome-like role.

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“…7,8) The R. leguminosarum three GroEL homologs show distinct in vitro properties, and only one of the three groEL genes is required for the growth of this organism. 8,9) Photosynthetic prokaryotic cyanobacteria generally have two copies of the groEL gene. [10][11][12] The groEL1 gene forms an operon with groES, whereas groEL2 is not accompanied by groES.…”

mentioning

confidence: 99%