Biomaterial Database

The molar ratio of sigma 73 to core polymerase in the obligate intracellular bacterium, Rickettsia prowazekii. 1994

H F Ding, and H H Winkler

Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile 36688.

In the obligate intracellular parasitic bacterium, Rickettsia prowazekii, the molar ratio of sigma 73 to core RNA polymerase, that is, the degree of saturation of the core polymerase by the catalytically active sigma factor, was very low. This ratio was determined from the radioactivity in rickettsial RNA polymerase immunoprecipitated from crude extracts of infected L929 cells in which the parasite was exponentially growing. If we assume that, as is true for the sigma subunit, in R. prowazekii and Escherichia coli the beta', and beta subunits of the RNA polymerase have similar methionine and cysteine contents (the radiolabelled amino acids), the molar ratio of sigma 73 to core polymerase in R. prowazekii would be 0.1. This is in striking contrast to E. coli where the ratio is typically 0.4. It remains to be established whether this low sigma saturation results in a limitation of active RNA polymerase in R. prowazekii and contributes to its slow growth.

UI	MeSH Term	Description	Entries
D007739	L Cells	A cultured line of C3H mouse FIBROBLASTS that do not adhere to one another and do not express CADHERINS.	Earle's Strain L Cells,L Cell Line,L Cells (Cell Line),L-Cell Line,L-Cells,L-Cells, Cell Line,L929 Cell Line,L929 Cells,NCTC Clone 929 Cells,NCTC Clone 929 of Strain L Cells,Strain L Cells,Cell Line L-Cell,Cell Line L-Cells,Cell Line, L,Cell Line, L929,Cell Lines, L,Cell, L,Cell, L (Cell Line),Cell, L929,Cell, Strain L,Cells, L,Cells, L (Cell Line),Cells, L929,Cells, Strain L,L Cell,L Cell (Cell Line),L Cell Lines,L Cell, Strain,L Cells, Cell Line,L Cells, Strain,L-Cell,L-Cell Lines,L-Cell, Cell Line,L929 Cell,Strain L Cell
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
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
D012283	Rickettsia prowazekii	A species of gram-negative, aerobic bacteria that is the etiologic agent of epidemic typhus fever acquired through contact with lice (TYPHUS, EPIDEMIC LOUSE-BORNE) as well as Brill's disease.
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
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
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus