| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Genetics and Molecular Biology |
Department of Biological Sciences1 and Howard Hughes Medical Institute2, Stanford University, Stanford, CA 94305, USA
Department of Biological Sciences, A527A Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA3
Author for correspondence: Valerie Oke. Tel: +1 412 624 4635. Fax: +1 412 624 4759. e-mail: voke{at}pitt.edu
Hybridization to a PCR product derived from conserved sigma-factor sequences led to the identification of two Sinorhizobium meliloti DNA segments that display significant sequence similarity to the family of rpoH genes encoding the 
32 (RpoH) heat-shock transcription factors. The first gene, rpoH1, complements an Escherichia coli rpoH mutation. Cells containing an rpoH1 mutation are impaired in growth at 37 °C under free-living conditions and are defective in nitrogen fixation during symbiosis with alfalfa. A plasmid-borne rpoH1–gusA fusion increases in expression upon entry of the culture into the stationary phase of growth. The second gene, designated rpoH2, is 42% identical to the S. meliloti rpoH1 gene. Cells containing an rpoH2 mutation have no apparent phenotype under free-living conditions or during symbiosis with the host plant alfalfa. An rpoH2–gusA fusion increases in expression during the stationary phase of growth. The presence of two rpoH-like sequences in S. meliloti is reminiscent of the situation in Bradyrhizobium japonicum, which has three rpoH genes.
Keywords: sigma-32, transcription factor, symbiosis, stress
The GenBank accession numbers for the sequences reported in this paper are AF128845 (rpoH1) and AF149031 (rpoH2).
a Present address: Department of Biology, Trinity University, 715 Stadium Drive, San Antonio, TX 78212, USA.
This article has been cited by other articles:
|
|
 |
|
  L. Sauviac, H. Philippe, K. Phok, and C. Bruand An Extracytoplasmic Function Sigma Factor Acts as a General Stress Response Regulator in Sinorhizobium meliloti J. Bacteriol., June 1, 2007; 189(11): 4204 - 4216. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. N. Bittner, A. Foltz, and V. Oke Only One of Five groEL Genes Is Required for Viability and Successful Symbiosis in Sinorhizobium meliloti J. Bacteriol., March 1, 2007; 189(5): 1884 - 1889. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Dominguez-Ferreras, R. Perez-Arnedo, A. Becker, J. Olivares, M. J. Soto, and J. Sanjuan Transcriptome Profiling Reveals the Importance of Plasmid pSymB for Osmoadaptation of Sinorhizobium meliloti J. Bacteriol., November 1, 2006; 188(21): 7617 - 7625. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Barra, C. Fontenelle, G. Ermel, A. Trautwetter, G. C. Walker, and C. Blanco Interrelations between Glycine Betaine Catabolism and Methionine Biosynthesis in Sinorhizobium meliloti Strain 102F34. J. Bacteriol., October 1, 2006; 188(20): 7195 - 7204. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. A. Green and T. J. Donohue Activity of Rhodobacter sphaeroides RpoHII, a Second Member of the Heat Shock Sigma Factor Family. J. Bacteriol., August 1, 2006; 188(16): 5712 - 5721. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. N. Bittner and V. Oke Multiple groESL Operons Are Not Key Targets of RpoH1 and RpoH2 in Sinorhizobium meliloti. J. Bacteriol., May 1, 2006; 188(10): 3507 - 3515. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Gao, H. Chen, A. Eberhard, M. R. Gronquist, J. B. Robinson, B. G. Rolfe, and W. D. Bauer sinI- and expR-Dependent Quorum Sensing in Sinorhizobium meliloti J. Bacteriol., December 1, 2005; 187(23): 7931 - 7944. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. H. Kaufusi, L. S. Forsberg, P. Tittabutr, and D. Borthakur Regulation of exopolysaccharide synthesis in Rhizobium sp. strain TAL1145 involves an alternative sigma factor gene, rpoH2 Microbiology, October 1, 2004; 150(10): 3473 - 3482. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. Peck, T. Gaal, R. F. Fisher, R. L. Gourse, and S. R. Long The RNA Polymerase {alpha} Subunit from Sinorhizobium meliloti Can Assemble with RNA Polymerase Subunits from Escherichia coli and Function in Basal and Activated Transcription both In Vivo and In Vitro J. Bacteriol., July 15, 2002; 184(14): 3808 - 3814. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
