Biomaterial Database

Regulation of a heat shock sigma32 homolog in Caulobacter crescentus. 1996

A Reisenauer, and C D Mohr, and L Shapiro

Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305-5427, USA.

High temperature and other environmental stresses induce the expression of several heat shock proteins in Caulobacter crescentus, including the molecular chaperones DnaJ, DnaK, GrpE, and GroEL and the Lon protease. We report here the isolation of the rpoH gene encoding a homolog of the Escherichia coli RNA polymerase sigma32 subunit, the sigma factor responsible for the transcription of heat shock promoters. The C. crescentus sigma32 homolog, predicted to be a 33.7-kDa protein, is 42% identical to E. coli sigma32 and cross-reacts with a monoclonal antibody to E. coli sigma32. Functional homology was demonstrated by complementing the temperature-sensitive growth defect of an E. coli rpoH deletion mutant with the C. crescentus rpoH gene. Immunoblot analysis showed a transient rise in sigma32 levels after a temperature shift from 30 to 42 degrees C similar to that described for E. coli. In addition, increasing the cellular content of sigma32 by introducing a plasmid-encoded copy of rpoH induced DnaK expression in C. crescentus cultures grown at 30 degrees C. The C. crescentus rpoH gene was transcribed from either of two heat shock consensus promoters. rpoH transcription and sigma32 levels increased coordinately following heat shock, indicating that transcriptional regulation contributes to sigma32 expression in this organism. Both the rpoH gene and sigma32 protein were expressed constitutively throughout the cell cycle at 30 degrees C. The isolation of rpoH provides an important tool for future studies of the role of sigma32 in the normal physiology of C. crescentus.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D011401	Promoter Regions, Genetic	DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.	rRNA Promoter,Early Promoters, Genetic,Late Promoters, Genetic,Middle Promoters, Genetic,Promoter Regions,Promoter, Genetic,Promotor Regions,Promotor, Genetic,Pseudopromoter, Genetic,Early Promoter, Genetic,Genetic Late Promoter,Genetic Middle Promoters,Genetic Promoter,Genetic Promoter Region,Genetic Promoter Regions,Genetic Promoters,Genetic Promotor,Genetic Promotors,Genetic Pseudopromoter,Genetic Pseudopromoters,Late Promoter, Genetic,Middle Promoter, Genetic,Promoter Region,Promoter Region, Genetic,Promoter, Genetic Early,Promoter, rRNA,Promoters, Genetic,Promoters, Genetic Middle,Promoters, rRNA,Promotor Region,Promotors, Genetic,Pseudopromoters, Genetic,Region, Genetic Promoter,Region, Promoter,Region, Promotor,Regions, Genetic Promoter,Regions, Promoter,Regions, Promotor,rRNA Promoters
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006360	Heat-Shock Proteins	Proteins which are synthesized in eukaryotic organisms and bacteria in response to hyperthermia and other environmental stresses. They increase thermal tolerance and perform functions essential to cell survival under these conditions.	Stress Protein,Stress Proteins,Heat-Shock Protein,Heat Shock Protein,Heat Shock Proteins,Protein, Stress
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D012808	Sigma Factor	A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.	Sigma Element,Sigma Initiation Factor,Sigma Subunit,Minor Sigma Factor,RNA Polymerase Sigma Factor H,Factor, Sigma,Factor, Sigma Initiation,Initiation Factor, Sigma,Sigma Factor, Minor,Subunit, Sigma