Regulatory interactions among the cya, crp and pts gene products in Salmonella typhimurium

1983 ◽  
Vol 192 (3) ◽  
pp. 477-486 ◽  
Author(s):  
Walter J. Dobrogosz ◽  
Gail W. Hall ◽  
Dayle K. Sherba ◽  
Daison O. Silva ◽  
James G. Harman ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Gene Products ◽  
Regulatory Interactions

scholarly journals The apbE Gene Encodes a Lipoprotein Involved in Thiamine Synthesis in Salmonella typhimurium

1998 ◽  
Vol 180 (4) ◽  
pp. 885-891 ◽  
Author(s):  
Brian J. Beck ◽  
Diana M. Downs
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Salmonella Typhimurium ◽  
De Novo ◽  
Open Reading Frame ◽  
Thiamine Pyrophosphate ◽  
Gene Products ◽  
Reading Frame ◽  
Purine Pathway

ABSTRACT Thiamine pyrophosphate is an essential cofactor that is synthesized de novo in Salmonella typhimurium. The biochemical steps and gene products involved in the conversion of aminoimidazole ribotide (AIR), a purine intermediate, to the 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) moiety of thiamine have yet to be elucidated. We have isolated mutations in a new locus (Escherichia coli open reading frame designation yojK) at 49 min on the S. typhimurium chromosome. Two significant phenotypes associated with lesions in this locus (apbE) were identified. First,apbE purF double mutants require thiamine, specifically the HMP moiety. Second, in the presence of adenine, apbE single mutants require thiamine, specifically both the HMP and the thiazole moieties. Together, the phenotypes associated with apbEmutants suggest that flux through the purine pathway has a role in regulating synthesis of the thiazole moiety of thiamine and are consistent with ApbE being involved in the conversion of AIR to HMP. The product of the apbE gene was found to be a 36-kDa membrane-associated lipoprotein, making it the second membrane protein implicated in thiamine synthesis.

scholarly journals HrcT Is a Key Component of the Type III Secretion System in Xanthomonas spp. and Also Regulates the Expression of the KeyhrpTranscriptional Activator HrpX

2014 ◽  
Vol 80 (13) ◽  
pp. 3908-3919 ◽  
Author(s):  
Zhi-Yang Liu ◽  
Li-Fang Zou ◽  
Xiao-Bo Xue ◽  
Lu-Lu Cai ◽  
Wen-Xiu Ma ◽  
...  
Keyword(s):  
Hypersensitive Response ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Regulatory Proteins ◽  
Gene Products ◽  
Phytopathogenic Bacteria ◽  
Content Type ◽  
Regulatory Interactions ◽  
Type Iii

ABSTRACTThe type III secretion system (T3SS), encoded byhrp(hypersensitive response and pathogenicity) genes in Gram-negative phytopathogenic bacteria, delivers repertoires of T3SS effectors (T3SEs) into plant cells to trigger the hypersensitive response (HR) in nonhost or resistant-host plants and promote pathogenicity in susceptible plants. The expression ofhrpgenes inXanthomonasis regulated by two key regulatory proteins, HrpG and HrpX. However, the interactions betweenhrpgene products in directing T3SE secretion are largely unknown. Here we demonstrated that HrcT ofX. oryzaepv. oryzicola functions as a T3SS component and positively regulates the expression ofhrpX. Transcription ofhrcToccurs via two distinct promoters; one (T1) is with thehrpBoperon and the second (T3) withinhrpB7Via either promoter T1 or T3, the defect in Hrp phenotype byhrcTdeletion was corrected in the presence ofhrcTonly fromXanthomonasspecies but not from other phytopathogenic bacteria. An N-terminally truncated HrcT was able to bind thehrpXpromoter and activate the expression ofhrpX, supporting that HrcT is a positive regulator ofhrpX. A revised model showing the regulatory interactions between HrcT, HrpX, and HrpG is proposed.

Overproduction of hisH and hisF gene products leads to inhibition of cell division in Salmonella

1972 ◽  
Vol 18 (5) ◽  
pp. 671-681 ◽  
Author(s):  
Michael L. Murray ◽  
Philip E. Hartman
Keyword(s):  
Cell Division ◽  
Carbon Source ◽  
Dna Synthesis ◽  
Salmonella Typhimurium ◽  
Nuclear Division ◽  
Direct Interaction ◽  
Pleiotropic Effects ◽  
Biosynthetic Enzymes ◽  
Gene Products ◽  
Low Carbon

Salmonella typhimurium derepressed for the histidine biosynthetic enzymes form wrinkled colonies at 37 °C on media containing a high (2%) content of metabolizable carbon source. "Wrinkledness" reflects accumulation of multinucleate filamentous cells caused by impaired cell division. At 42 °C, DNA synthesis and nuclear division are impaired. Addition of methionine at 42 °C permits DNA synthesis, nuclear division, and, under some conditions, cell division. However, multinucleate filaments are formed both on high and on low carbon source at 42 °C. The filaments contain nuclei that are peculiarly hypersensitive to inactivation with ultraviolet (uv.) light.Overproduction of both the hisH and hisF gene products is required for these pleiotropic effects of derepression. The hisH and hisF proteins, and even some of their enzymologically inactive forms, may cooperate to inhibit cell division by direct interaction with (a) sensitive cellular site(s).

Identification of a baculovirus polyhedron formation mutant with a novel phenotype

1996 ◽  
Vol 54 ◽  
pp. 796-797
Author(s):  
James M. Slavicek ◽  
Melissa J. Mercer ◽  
Mary Ellen Kelly
Keyword(s):  
Viral Gene ◽  
Gene Products ◽  
Type Number ◽  
Infection Cycle ◽  
Wild Type ◽  
Protein Matrix ◽  
Insect Midgut ◽  
Viral Particles ◽  
Budded Virus ◽  
Viral Form

Nucleopolyhedroviruses (NPV, family Baculoviridae) produce two morphological forms, a budded virus form and a viral form that is occluded into a paracrystalline protein matrix. This structure is termed a polyhedron and is composed primarily of the protein polyhedrin. Insects are infected by NPVs after ingestion of the polyhedron and release of the occluded virions through dissolution of the polyhedron in the alkaline environment of the insect midgut. Early after infection the budded virus form is produced. It buds through the plasma membrane and then infects other cells. Later in the infection cycle the occluded form of the virus is generated (reviewed by Blissard and Rohrmann, 1990).The processes of polyhedron formation and virion occlusion are likely to involve a number of viral gene products. However, only two genes, the polyhedrin gene and 25K FP gene, have been identified to date that are necessary for the wild type number of polyhedra to be formed and viral particles occluded.

New insights into heparan sulphate biosynthesis from the study of mutant mice

2002 ◽  
Vol 69 ◽  
pp. 47-57 ◽  
Author(s):  
Catherine L. R. Merry ◽  
John T. Gallagher
Keyword(s):  
Growth Factors ◽  
Biosynthetic Pathway ◽  
Heparan Sulphate ◽  
Mutant Mice ◽  
Gene Products ◽  
Multiple Gene ◽  
Adhesion Proteins ◽  
Ligand Interactions

Heparan sulphate (HS) is an essential co-receptor for a number of growth factors, morphogens and adhesion proteins. The biosynthetic modifications involved in the generation of a mature HS chain may determine the strength and outcome of HS–ligand interactions. These modifications are catalysed by a complex family of enzymes, some of which occur as multiple gene products. Various mutant mice have now been generated, which lack the function of isolated components of the HS biosynthetic pathway. In this discussion, we outline the key findings of these studies, and use them to put into context our own work concerning the structure of the HS generated by the Hs2st-/- mice.

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