A HU‐like gene mutation in <i>Rhizobium leguminosarum</i> bv. <i>viciae</i> affects the expression of nodulation genes

Li, Qiang; Feng, Jie; Hu, Hailiang; Chen, Xiaochun; Li, Feng-Qing; Hong, Guofan

doi:10.1046/j.1365-2958.2003.03873.x

Cited by 10 publications

(8 citation statements)

References 62 publications

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“…Recently, we cloned and sequenced a gene named hurl from R.leguminosarum bv. viciae coding for the HU-like protein Hurl, which was previously observed to bind specifically to nod promoters and be involved in in vitro nodD transcription (4,40,41). Inactivation of hurL led to severe impairment in the nodD expression, repression in the inducible expression of nodA and nodF .…”

Section: Discussionmentioning

confidence: 99%

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Modulating DNA bending affects NodD-mediated transcriptional control in Rhizobium leguminosarum

Chen

2005

Nucleic Acids Research

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Rhizobium leguminosarum NodD binds to the nod box of the inducible nod gene nodA as a V-shaped tetramer and bends the nod box. In this work, we show that the nod gene inducer naringenin decreased gel mobility of nod box DNA–NodD complexes by sharpening the NodD-induced DNA bend, which correlated with nodA transcription activation. NodD can induce different DNA bends when the distance between the two half-sites of the nod box was modified, which severely affected NodD-mediated transcriptional control. One or two base pairs were deleted from, or inserted into, the two half-sites of the nod box of nodA. Circular permutation assays showed that such distance modulations allowed NodD to induce relaxed or sharpened DNA bending. In the case of 1 bp deletion, where the DNA bends were more relaxed than in the wild type, nodA transcription was repressed both in the absence and in the presence of inducer naringenin. In the cases of 1 and 2 bp insertion, where the DNA bends were much sharper than in wild type in the absence or presence of the inducer naringenin, nodA transcription was initiated constitutively with no requirement for the inducer naringenin or, even, the NodD regulating protein.

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Section: Discussionmentioning

confidence: 99%

“…These results suggested that hurL might be required for maintaining the normal expression of nod genes in R.leguminosarum bv. viciae (41). Moreover, such protein playing important roles in the global and basic biological events as the molecular chaperone groELc has been reported may take part in the transcription regulation of nod gene (42).…”

Section: Discussionmentioning

confidence: 99%

Modulating DNA bending affects NodD-mediated transcriptional control in Rhizobium leguminosarum

Chen

2005

Nucleic Acids Research

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“…Also, a histonelike protein, HurL, which binds specifically to nod gene promoters, has been identified in R. leguminosarum bv. viciae, and its role in the in vitro transcription of nodD, which encodes a major regulator of the expression of nod genes in rhizobia, has been demonstrated (Yang et al, 2000;Li et al, 2004). Even more interestingly, an IHF protein has been implicated in the auto-activation of NifA in Herbaspirillum seropedicae (Wassem et al, 2000(Wassem et al, , 2002.…”

Section: Discussionmentioning

confidence: 99%

Interaction of an IHF-like protein with the Rhizobium etli nifA promoter

Benhassine

Fauvart

Vanderleyden

et al. 2007

FEMS Microbiology Letters

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The nifA gene fulfills an essential role in the regulation of nitrogen fixation genes in Rhizobium etli. Transcription analysis of the nifA gene, assessed using promoter deletions, indicated an oxygen-independent expression, threefold higher during symbiosis as compared with free-living conditions. Electrophoretic mobility shift assays using those nifA promoter deletion fragments, which were actively transcribed, demonstrated the specific interaction with R. etli cellular protein(s) resulting in the formation of two DNA-protein complexes. An interacting protein was purified by liquid chromatography on Heparin Sepharose and Mono S columns. The purified 12 kDa R. etli protein cross-reacted with antibodies directed against Escherichia coli integration host factor (IHF). Furthermore, purified E. coli IHF was able to specifically bind to the R. etli nifA promoter region. These results point to an as yet undisclosed function of IHF in the regulation of R. etli nifA expression.

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“…The plasmids were transferred from E. coli S17-1 to R. leguminasorum bv. viciae 8401 containing either pMP221A or pMP220D [53] by biparental conjugation. The resulting clones were sequenced by Sangon Company (Shanghai, China).…”

Section: Microbiological Techniquesmentioning

confidence: 99%

The properties of NodD were affected by mere variation in length within its hinge region

Hou¹,

Li²,

Yang³

et al. 2009

ABBS

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In Rhizobium leguminosarum bv. viciae, NodD, a member of the LysR-type transcriptional regulators, while auto-regulating, activates transcription of other nod genes in the presence of naringenin. A hinge region of NodD was previously identified in our laboratory as a functional region independent of its N-terminal DNA-binding and C-terminal regulatory domain. Further study was carried out to see the possible effect of the length variation in the hinge region on NodD's properties. To our surprise, as many as seven classes of phenotypes were observed. Class I is deficient of activating nodA transcription and abolishes auto-regulation; class II is able to activate nodA transcription independently of naringenin and abolishes auto-regulation; class III retains autoregulating but partial activating ability; class IV is able to activate transcription independently of naringenin and retains auto-regulation; in class V, nodA is transcribed constitutively but the transcription level is drastically down-regulated in the presence of naringenin; in class VI, nodA is transcribed constitutively with higher induction ratio; in class VII, nodA is transcribed constitutively with lower induction ratio. To learn more about the possible mechanism, circular permutation assays were done, which showed that the length variation of the hinge of NodD caused by mutation led to the change in bend angles of nod promoter. This finding should help to get an insight into how transcriptional regulation is mediated by NodD at the molecular level as well as to understand the regulatory system of this important family.

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A HU‐like gene mutation in Rhizobium leguminosarum bv. viciae affects the expression of nodulation genes

Cited by 10 publications

References 62 publications

Modulating DNA bending affects NodD-mediated transcriptional control in Rhizobium leguminosarum

Modulating DNA bending affects NodD-mediated transcriptional control in Rhizobium leguminosarum

Interaction of an IHF-like protein with the Rhizobium etli nifA promoter

The properties of NodD were affected by mere variation in length within its hinge region

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