scholarly journals Regulatory mechanism of the tryptophan operon in Escherichia coli: Possible interaction between trpR and trpS gene products

1972 ◽  
Vol 115 (4) ◽  
pp. 349-363 ◽  
Author(s):  
Koreaki Ito
Keyword(s):  
Escherichia Coli ◽  
Regulatory Mechanism ◽  
Gene Products ◽  
Tryptophan Operon

Involvement of the nusA and nusB gene products in transcription of Escherichia coli tryptophan operon in vitro

1982 ◽  
Vol 185 (2) ◽  
pp. 369-371 ◽  
Author(s):  
Kazuyuki Kuroki ◽  
Shunsuke Ishii ◽  
Yasunobu Kano ◽  
Tomoyuki Miyashita ◽  
Kayoko Nishi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Products ◽  
Tryptophan Operon

scholarly journals TRANSLATIONAL COUPLING DURING EXPRESSION OF THE TRYPTOPHAN OPERON OF ESCHERICHIA COLI

Genetics ◽  
1980 ◽  
Vol 95 (4) ◽  
pp. 785-795 ◽  
Author(s):  
Daniel S Oppenheim ◽  
Charles Yanofsky
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Gene Products ◽  
Translational Coupling ◽  
E Coli ◽  
Functional Complex ◽  
Tryptophan Operon

ABSTRACT E. coli trpE polar mutations are 10 times more polar on trpD gene expression than on downstream (trpC, B, or A) gene expression. This effect was shown to be the result of "translational coupling," in which efficient translation of trpD mRNA reqiures efficient translation of the end of trpE mRNA. The trpE-trpD intercistronic punctuation region consists of overlapping stop and start codons, and the trpE and trpD gene products form a functional complex in the cell. In light of these observations and characteristics, several models for the mechanism of translational coupling are considered.

scholarly journals Physical and genetic characterization of the melibiose operon and identification of the gene products in Escherichia coli.

1984 ◽  
Vol 259 (3) ◽  
pp. 1807-1812 ◽  
Author(s):  
M Hanatani ◽  
H Yazyu ◽  
S Shiota-Niiya ◽  
Y Moriyama ◽  
H Kanazawa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Characterization ◽  
Gene Products

scholarly journals Identification of the Gene Encoding Sulfopyruvate Decarboxylase, an Enzyme Involved in Biosynthesis of Coenzyme M

2000 ◽  
Vol 182 (17) ◽  
pp. 4862-4867 ◽  
Author(s):  
Marion Graupner ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Escherichia Coli ◽  
Second Step ◽  
Gene Products ◽  
Methanococcus Jannaschii ◽  
Coenzyme M ◽  
Gene Encoding ◽  
Fourth Step

ABSTRACT The products of two adjacent genes in the chromosome ofMethanococcus jannaschii are similar to the amino and carboxyl halves of phosphonopyruvate decarboxylase, the enzyme that catalyzes the second step of fosfomycin biosynthesis inStreptomyces wedmorensis. These two M. jannaschii genes were recombinantly expressed inEscherichia coli, and their gene products were tested for the ability to catalyze the decarboxylation of a series of α-ketoacids. Both subunits are required to form an α6β6 dodecamer that specifically catalyzes the decarboxylation of sulfopyruvic acid to sulfoacetaldehyde. This transformation is the fourth step in the biosynthesis of coenzyme M, a crucial cofactor in methanogenesis and aliphatic alkene metabolism. The M. jannaschiisulfopyruvate decarboxylase was found to be inactivated by oxygen and reactivated by reduction with dithionite. The two subunits, designated ComD and ComE, comprise the first enzyme for the biosynthesis of coenzyme M to be described.

Evidence for two recA genes mediating DNA repair in Bacillus megaterium

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 775-787 ◽  
Author(s):  
Hannes Nahrstedt ◽  
Christine Schröder ◽  
Friedhelm Meinhardt
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mitomycin C ◽  
Bacillus Megaterium ◽  
Functional Complementation ◽  
Homologous Gene ◽  
Gene Products ◽  
Null Mutant ◽  
Promoter Regions ◽  
Increased Sensitivity

Isolation and subsequent knockout of a recA-homologous gene in Bacillus megaterium DSM 319 resulted in a mutant displaying increased sensitivity to mitomycin C. However, this mutant did not exhibit UV hypersensitivity, a finding which eventually led to identification of a second functional recA gene. Evidence for recA duplicates was also obtained for two other B. megaterium strains. In agreement with potential DinR boxes located within their promoter regions, expression of both genes (recA1 and recA2) was found to be damage-inducible. Transcription from the recA2 promoter was significantly higher than that of recA1. Since a recA2 knockout could not be achieved, functional complementation studies were performed in Escherichia coli. Heterologous expression in a RecA null mutant resulted in increased survival after UV irradiation and mitomycin C treatment, proving both recA gene products to be functional in DNA repair. Thus, there is evidence for an SOS-like pathway in B. megaterium that differs from that of Bacillus subtilis.

scholarly journals The complete nucleotide sequence of the tryptophan operon of Escherichia coli

1981 ◽  
Vol 9 (24) ◽  
pp. 6647-6668 ◽  
Author(s):  
C. Yanofsky ◽  
T. Platt ◽  
I.P. Crawford ◽  
B.P. Nichols ◽  
G.E. Christie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Complete Nucleotide Sequence ◽  
Tryptophan Operon

scholarly journals Quorum Sensing Is a Global Regulatory Mechanism in Enterohemorrhagic Escherichia coli O157:H7

2001 ◽  
Vol 183 (17) ◽  
pp. 5187-5197 ◽  
Author(s):  
Vanessa Sperandio ◽  
Alfredo G. Torres ◽  
Jorge A. Girón ◽  
James B. Kaper
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Mechanism ◽  
Sos Response ◽  
Enterohemorrhagic Escherichia Coli ◽  
Trna Genes ◽  
Wild Type ◽  
E Coli

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for outbreaks of bloody diarrhea and hemolytic-uremic syndrome in many countries. EHEC virulence mechanisms include the production of Shiga toxins (Stx) and formation of attaching and effacing (AE) lesions on intestinal epithelial cells. We recently reported that genes involved in the formation of the AE lesion were regulated by quorum sensing through autoinducer-2, which is synthesized by the product of the luxS gene. In this study we hybridized an E. coli gene array with cDNA synthesized from RNA that was extracted from EHEC strain 86-24 and its isogenicluxS mutant. We observed that 404 genes were regulated by luxS at least fivefold, which comprises approximately 10% of the array genes; 235 of these genes were up-regulated and 169 were down-regulated in the wild-type strain compared to in theluxS mutant. Down-regulated genes included several involved in cell division, as well as ribosomal and tRNA genes. Consistent with this pattern of gene expression, theluxS mutant grows faster than the wild-type strain (generation times of 37.5 and 60 min, respectively, in Dulbecco modified Eagle medium). Up-regulated genes included several involved in the expression and assembly of flagella, motility, and chemotaxis. Using operon::lacZ fusions to class I, II, and III flagellar genes, we were able to confirm this transcriptional regulation. We also observed fewer flagella by Western blotting and electron microscopy and decreased motility halos in semisolid agar in the luxS mutant. The average swimming speeds for the wild-type strain and the luxS mutant are 12.5 and 6.6 μm/s, respectively. We also observed an increase in the production of Stx due to quorum sensing. Genes encoding Stx, which are transcribed along with λ-like phage genes, are induced by an SOS response, and genes involved in the SOS response were also regulated by quorum sensing. These results indicate that quorum sensing is a global regulatory mechanism for basic physiological functions of E. coli as well as for virulence factors.

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