Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ca2+-ATPase molecules present in the microsomal fraction from non-muscle cells were examined immunologically. Rabbit whole brain, cerebellum, liver, kidney, and COS-1 cell microsomes all displayed a polypeptide of about 110 kDa which was immunoreactive with a polyclonal antiserum against the cardiac muscle sarcoplasmic reticulum Ca2+-ATPase molecule, but was not immunoreactive with a monoclonal antibody specific for the fast-twitch muscle Ca2+-ATPase. cDNAs encoding the full length of two Ca2+-ATPase molecules were isolated from a human kidney library using a mixture of nucleotide probes derived from both rabbit fast-twitch and cardiac muscle Ca2+-ATPase cDNAs. The human kidney cDNAs, HK1 and HK2, are the products of alternative splicing. HK2 codes for a protein identical to rabbit cardiac muscle Ca2+-ATPase, with the exception of 6 scattered amino acid replacements, whereas HK1 codes for a protein identical to that encoded by HK2, but with the carboxyl-terminal 4 amino acids replaced by an extended sequence of 49 amino acids. cDNAs of the HK1 type are by far the most abundant in the library. The partial structure of a 40-kilobase genomic DNA encoding all but the 5' end of the human cardiac Ca2+-ATPase is described. The exons which give rise to the alternatively spliced products were located by Southern blotting and sequencing, and the alternative splicing patterns were determined.
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PMID:Molecular cloning of cDNAs from human kidney coding for two alternatively spliced products of the cardiac Ca2+-ATPase gene. 284 96

The ompB operon of Salmonella typhimurium encodes a positive transcriptional regulator OmpR and an inner membrane protein EnvZ. Both proteins are needed for the proper expression of the outer membrane proteins OmpC and OmpF. We have determined the nucleotide sequence of the ompB locus and its adjacent regions. A comparison between the S. typhimurium and Escherichia coli sequences revealed that the ompB locus is highly conserved. The sequence data also showed that ompR and envZ form an operon, where the coding regions overlap by four base-pairs. Utilizing ompR-lacZ and envZ-lacZ gene fusions, the translational levels of expression of these two genes were measured, showing that ompR is considerably more efficiently expressed than envZ. Analysis of ompR frameshift mutations showed that translation of envZ is almost totally dependent on the translation of the upstream gene ompR. The mechanism of this translational coupling appears to be a reinitiation of the ribosome at the overlapping region of the two genes. The characteristics of the OmpR and EnvZ proteins were in agreement with the known functions and cellular locations of these proteins. OmpR was found to contain a putative DNA binding site, while EnvZ contained two hydrophobic stretches typical of transmembrane regions. Both OmpR and EnvZ show extensive homologies with many proteins from a number of different origins, all of which function in pairs and through which environmental signals modulate gene expression. Hence, the tightly coupled synthesis of these proteins seems to be essential in eliciting a proper response in the transmembrane regulation of gene expression.
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PMID:Structure and expression of the ompB operon, the regulatory locus for the outer membrane porin regulon in Salmonella typhimurium LT-2. 284 93

The expression of the genes encoding the major outer membrane porin proteins OmpF and OmpC in Escherichia coli is regulated by ompR, which encodes the transcriptional activator protein OmpR, and envZ, which encodes a receptorlike protein located in the inner membrane. To examine the role of EnvZ in the expression of the osmoregulated porin genes, we analyzed the production of OmpF and OmpC in cells that lack envZ function. We show that EnvZ is required for the maximal production of OmpC in cells grown in minimal medium but is not essential for the efficient induction of OmpC that occurs during a shift to a high-osmolarity medium. In contrast, the production of OmpF in cells that lack envZ function was similar to that of the parent strain, whereas OmpF repression during a shift to a high-osmolarity medium was incomplete in the absence of EnvZ. These results are discussed in the context of the putative role of EnvZ in the expression of ompF and ompC.
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PMID:Regulation of ompC and ompF expression in Escherichia coli in the absence of envZ. 284 9

The ompB operon of Escherichia coli contains the structural genes for two proteins, OmpR and EnvZ, which control the osmoregulated biosynthesis of the porin proteins OmpF and OmpC. By inserting XbaI octamer linkers into the cloned ompB locus, four distinct frameshift mutants were isolated and subsequently characterized for their OmpR and EnvZ protein products and their outer membrane porin phenotype. In a minicell expression system, the wild-type products of the ompR and envZ genes were found to be approximately 28 and 50 kilodaltons in size, respectively, whereas the mutant proteins were either truncated or extended due to the frame shift. The identity of the envZ gene product was confirmed by immunoprecipitation. M13 dideoxy sequencing of the DNA around the wild-type ompR-envZ junction revealed an error in the sequence published for this operon; the complete corrected sequence is presented. A sequence, ATGA, was found that forms the termination codon for the OmpR reading frame and a possible initiation codon for the EnvZ protein; these sequences are consistent with the sizes of the proteins observed after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The translational activity of this ATG codon was confirmed by fusing the lacZ gene in frame with the putative EnvZ coding sequence. The implications of these results are discussed with respect to the regulation of synthesis of the ompB gene products.
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PMID:Primary characterization of the protein products of the Escherichia coli ompB locus: structure and regulation of synthesis of the OmpR and EnvZ proteins. 299 20

Previous studies described lacZ'- and cat'-'cpxA fusion genes whose expression restored to normal all the phenotypic defects associated with cpxA mutations (Albin, R., and Silverman, P. M. (1984) Mol. Gen. Genet. 197, 272-279). Here, we show by DNA nucleotide sequence analysis that the fusion genes encode 241 carboxyl-terminal amino acids of the CpxA polypeptide. Using this information, we constructed a fusion gene containing the same 241 cpxA codons preceded by 1007 codons of beta-galactosidase. The resultant hybrid polypeptide was purified and used to raise an anti-(CpxA polypeptide) antiserum. Using the antiserum, we have identified the chromsomal Escherichia coli K12 cpxA gene product as a 52-kDa polypeptide. The polypeptide showed temperature-sensitive accumulation in a strain carrying both the cpxA2[Ts] and cpxB1 alleles and accumulated to a level higher than normal in cells that carried a high-copy number, cpxA+ plasmid. Immune precipitates of in vitro transcription-translation reactions with cpxA+ plasmids as template also contained a 52-kDa polypeptide, indistinguishable in electrophoretic mobility from the immunoreactive polypeptide synthesized in vivo. Two regions of amino acid sequence at the carboxyl-terminus of the CpxA polypeptide are significantly homologous to corresponding regions of the E. coli K12 EnvZ polypeptide, an inner membrane component that, like the CpxA polypeptide, is required to maintain the protein composition of the cell envelope. The cpxA coding sequence is followed by two repetitive extragenic palindrome sequences in opposite orientation.
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PMID:The Cpx proteins of Escherichia coli K12. Immunologic detection of the chromosomal cpxA gene product. 300 73

The tppB locus of Salmonella typhimurium encodes the anaerobically-induced tripeptide permease. We have demonstrated that expression of tppB requires the function of the ompR and envZ gene products, originally identified as positive regulatory proteins required for the osmotic regulation of porin expression. Significantly, tppB expression is not osmotically regulated. We have also identified three additional genes whose expression depends on OmpR. Thus OmpR and EnvZ serve a more general regulatory role than has previously been supposed. This study provides the first detailed genetic analysis of the ompB locus of S. typhimurium.
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PMID:OmpR and EnvZ are pleiotropic regulatory proteins: positive regulation of the tripeptide permease (tppB) of Salmonella typhimurium. 303 76

T-2 toxin, a trichothecene mycotoxin, inhibits the growth of Saccharomyces cerevisiae. We have isolated nine spontaneous S. cerevisiae mutants resistant to this toxin. The mutants were distinguished from the wild type according to their degree of resistance to T-2 toxin on media with dextrose or glycerol as the carbon source. Generation time, mutation stability and level of cross-resistance to roridin A, another trichothecene, were determined for each mutant. The T-2 toxin resistant mutants were further characterized by subsequent tests involving cross-resistance and collateral sensitivity to chlorampenicol, neomycin, paromomycin, ethidium bromide and thiolutin. Mutants have been placed into three subgroups and the mechanism of T-2 toxin resistance in each group has been postulated. Mutant HK1 is the first S. cerevisiae isolate resistant to roridin A. One particular isolate, mutant HK11, carries a single recessive nuclear mutation. This mutation was termed ttt (for T-2 toxin resistant).
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PMID:Isolation and characterization of Saccharomyces cerevisiae mutants resistant to T-2 toxin. 304 65

The uhpABCT locus of Escherichia coli is responsible for expression of the sugar-phosphate transport system and its induction by external glucose 6-phosphate. Expression of uhpT-lacZ fusions depended on the function of uhpA, uhpB, and uhpC but not of uhpT. A plasmid carrying only uhpT conferred transport activity in a host strain deleted for the uhp region. Thus, uhpT encodes the polypeptide required for transport function, and the other three uhp genes regulate uhpT transcription. The presence of uhpA at elevated copy number resulted in a substantial increase in uhpT expression. This elevated expression was only about 50% of the level seen in induced haploid cells, and no further increase occurred after addition of inducer. Activation by multicopy uhpA was not affected by the status of uhpC but was decreased in the absence of uhpB, suggesting a role for UhpB in directly activating UhpA. Transcription of uhpA, monitored by expression of a uhpA-lacZ fusion, was not affected by either inducer or the presence of the wild-type uhpA allele. The presence of multiple copies of the uhpT promoter region reduced uhpT expression in strains with uhpA in single copy number but not in those with multiple copies, consistent with competition for the activator. Amino acid sequence comparisons showed that UhpA was homologous to a family of bacterial regulatory proteins, some of which act as transcriptional activators (OmpR, PhoB, NtrC, and DctD). The C-terminal portion of UhpB displayed matches to the corresponding portions of another family of proteins (EnvZ, PhoMR, NtrB, and DctB) that participate in regulation of gene expression in response to environmental factors.
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PMID:Role of uhp genes in expression of the Escherichia coli sugar-phosphate transport system. 304 48

By fusing the transcriptional and translational start signals of lacZ to envZ, we have obtained high-level synthesis of a truncated EnvZ protein (EnvZ115) in which the first 38 amino acids of EnvZ are replaced with the first 8 amino acids of LacZ. Using this construct, we have partially purified the EnvZ115 protein and demonstrated that this protein can be phosphorylated in vitro. We suggest that phosphorylation may be an important feature of EnvZ function.
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PMID:EnvZ, a transmembrane environmental sensor of Escherichia coli K-12, is phosphorylated in vitro. 305 29

We isolated a series of delta ompR delta envZ mutants by inducing a strain carrying a lambda prophage in the closely linked gene malP and screening the bacterial survivors for loss of the major outer membrane porins OmpF and OmpC. Characterization of these deletion strains showed that both OmpR and EnvZ were necessary for transcription of ompF and ompC and that neither gene was essential for cell viability. Moreover, the deletion strains did not exhibit the pleiotropic membrane protein deficiency observed with certain envZ mutants. The method described should allow the simple isolation of deletions in any region of the chromosome.
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PMID:Isolation and characterization of delta ompB strains of Escherichia coli by a general method based on gene fusions. 315 79


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