The 660 bp region between nodD3 P1 promoter and the following coding region of Rnizopium meliloti has been studied. This region is designated 'downstream sequences' . it consists of two potential open reading ...The 660 bp region between nodD3 P1 promoter and the following coding region of Rnizopium meliloti has been studied. This region is designated 'downstream sequences' . it consists of two potential open reading frames, ORF1 and ORF2. Studies on the role of the downstream sequences on the activity of nooD3 P1 with nod D3(P1)-/acZ fusion show that deletion of the seguences containing ORF2 causes the increase of the activity of the fusion; on the contrary, addition of extra copies of ORF2 markedly decreases the activity of the fusion. These results indicate that the product of ORF2 plays a negative role in the expression of nod D3.展开更多
In Sinorhizobium meliloti, the nodD3 gene is transcriptionally controlled by two promot-ers, P1 and P2. Under P1, there is a 660 bp sequence including a small open reading frame, ORF2, followed by the nodD3 coding reg...In Sinorhizobium meliloti, the nodD3 gene is transcriptionally controlled by two promot-ers, P1 and P2. Under P1, there is a 660 bp sequence including a small open reading frame, ORF2, followed by the nodD3 coding region. Genetic analysis using the different deletions on the 3′ends of P1 downstream sequence showed that the downstream sequence +1—+125nt is es-sential for P1 expression. Complementation, mutations and nodulation tests demonstrated that the ORF2 auto-represses P1 expression, while the P1 downstream sequence +1—+125nt counteracts it.展开更多
Nodulation is crucial for the symbiosis between Rhizobia and plants, and 13 nod genes have been identified in Rhizobium leguminosarum biovar (bv.) viciae, which are responsible for the formation of nodules on plant ro...Nodulation is crucial for the symbiosis between Rhizobia and plants, and 13 nod genes have been identified in Rhizobium leguminosarum biovar (bv.) viciae, which are responsible for the formation of nodules on plant roots. The nodD, one of those nod genes, is an autoregulatory gene, which controls the expressions of all the rest nod genes in the展开更多
NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footpri...NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footprinting. A series of techniques based on gel retardation were used to analyze the NodD_target DNA interaction, showing that NodD binds to target DNA in isologous octamer.展开更多
R.meliloti nodD3 gene is transcriptionally controlled by two promoters.Gel retardationexperiments show that SyrM and NodD3 are binding to the first promoter region of nodD3,while no proteinfactor is found to bind to t...R.meliloti nodD3 gene is transcriptionally controlled by two promoters.Gel retardationexperiments show that SyrM and NodD3 are binding to the first promoter region of nodD3,while no proteinfactor is found to bind to the second promoter region of the gene.Comparison has been made between 5′ non-coding region of nodD3 and the corresponding region upstream of nodD1.The presence of nod-box andnodA-like sequences in the 5′ noncoding region of nodD3 supports the hypothesis that nodD3 evolves withthe duplication of the nodD1-nodA fragment during the speciation of R.meliloti.展开更多
In Rhizobium leguminosarum (R.1.) biovar viciae, the nodulation (nod) gene D encodes a transcriptional activator (NodD). It also represses nodD transcription,and this autoregulation occurs at the divergent and overlap...In Rhizobium leguminosarum (R.1.) biovar viciae, the nodulation (nod) gene D encodes a transcriptional activator (NodD). It also represses nodD transcription,and this autoregulation occurs at the divergent and overlapping nodA-nodD promoters.展开更多
文摘The 660 bp region between nodD3 P1 promoter and the following coding region of Rnizopium meliloti has been studied. This region is designated 'downstream sequences' . it consists of two potential open reading frames, ORF1 and ORF2. Studies on the role of the downstream sequences on the activity of nooD3 P1 with nod D3(P1)-/acZ fusion show that deletion of the seguences containing ORF2 causes the increase of the activity of the fusion; on the contrary, addition of extra copies of ORF2 markedly decreases the activity of the fusion. These results indicate that the product of ORF2 plays a negative role in the expression of nod D3.
基金This work was supported by the National High Technology 863 Programs of China the 973 Project of the Ministry of Science and Technology (Grant No. 001CB108901) and the fund of the Shanghai Institutes of Biological Sciences.
文摘In Sinorhizobium meliloti, the nodD3 gene is transcriptionally controlled by two promot-ers, P1 and P2. Under P1, there is a 660 bp sequence including a small open reading frame, ORF2, followed by the nodD3 coding region. Genetic analysis using the different deletions on the 3′ends of P1 downstream sequence showed that the downstream sequence +1—+125nt is es-sential for P1 expression. Complementation, mutations and nodulation tests demonstrated that the ORF2 auto-represses P1 expression, while the P1 downstream sequence +1—+125nt counteracts it.
文摘Nodulation is crucial for the symbiosis between Rhizobia and plants, and 13 nod genes have been identified in Rhizobium leguminosarum biovar (bv.) viciae, which are responsible for the formation of nodules on plant roots. The nodD, one of those nod genes, is an autoregulatory gene, which controls the expressions of all the rest nod genes in the
文摘NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footprinting. A series of techniques based on gel retardation were used to analyze the NodD_target DNA interaction, showing that NodD binds to target DNA in isologous octamer.
基金the National Natural Science Foundation of China.
文摘R.meliloti nodD3 gene is transcriptionally controlled by two promoters.Gel retardationexperiments show that SyrM and NodD3 are binding to the first promoter region of nodD3,while no proteinfactor is found to bind to the second promoter region of the gene.Comparison has been made between 5′ non-coding region of nodD3 and the corresponding region upstream of nodD1.The presence of nod-box andnodA-like sequences in the 5′ noncoding region of nodD3 supports the hypothesis that nodD3 evolves withthe duplication of the nodD1-nodA fragment during the speciation of R.meliloti.
文摘In Rhizobium leguminosarum (R.1.) biovar viciae, the nodulation (nod) gene D encodes a transcriptional activator (NodD). It also represses nodD transcription,and this autoregulation occurs at the divergent and overlapping nodA-nodD promoters.
