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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Characterization of ternary complexes containing an Escherichia coli lac promoter DNA fragment, CAP protein and RNA polymerase, separated on non-denaturing polyacrylamide gels and footprinted in the gel slice, reveals a striking stabilization of CAP against dissociation in the open complex, compared to the CAP-DNA complex lacking RNA polymerase. The stabilization is lost when half a helical turn of DNA is inserted between CAP and polymerase sites, but is partially restored with an 11 base-pair insert; stimulation of transcription parallels the stabilization effect. This behavior suggests a direct protein-protein interaction. Comparison of initiation kinetics for wild-type and a mutant in which the P2 promoter has been inactivated shows that CAP both strengthens binding in the closed complex and accelerates isomerization to the open complex; the latter effect accounts for the bulk of the observed transcriptional activation.
J Mol Biol 1989 Mar 05
PMID:Synergy between Escherichia coli CAP protein and RNA polymerase in the lac promoter open complex. 264 87

In enteric bacteria, the expression of many genes encoding various anaerobic electron transfer functions is controlled by FNR, the product of the autoregulated fnr gene. FNR is structurally and functionally homologous to CAP, the catabolite gene activator protein, and increased FNR production strongly stimulates transcription of its target genes. By analysis of RNA produced in vivo the promoters of four FNR-dependent genes were localized and shown to display a common arrangement. A 22bp dyad symmetry was found about 30 nucleotides upstream of the transcriptional startpoints and a similar sequence was shown to overlap the site of transcription initiation in the negatively controlled fnr gene. The consensus sequence for the half site recognized by FNR (AAA-TTGAT) is only slightly different from that of CAP (AA-TGTGA). Studies with two mutant frd promoters from Escherichia coli, displaying altered regulation and FNR response, provided additional evidence for recognition of this sequence by FNR.
Mol Microbiol 1989 Jul
PMID:Molecular genetic analysis of FNR-dependent promoters. 267 2

The expression of colicin genes is controlled by the SOS-system (Lex A repressor) and the adenylate-cyclase system (cAMP-CAP complex). The effect of plasmid DNA supercoiling on the expression of the operons of colicins E1, E2, and E3 has been studied by using E. coli minicells. It has been shown for the colicin E1 operon that it is the promoter that is influenced by supercoiling: an increase in negative supercoiling elevates the expression and, vice versa, DNA relaxation reduces the expression. The effect of supercoiling on gene activity of the colicin E1 immunity protein has not been observed, which may be due to the specific orientation of this gene. With the two other colicins supercoiling affects the expression of all genes which constitute the operon. The regulation of the colicin operon expression has been confirmed to occur at three levels: by the LexA protein, by the cAMP-CAP complex, and by the plasmid DNA supercoiling.
Mol Biol (Mosk)
PMID:[The effect of supercoiling of DNA from colicinogenic plasmids on the expression of col, imm and lys genes]. 269 78

The binding of the cyclic adenosine 3',5' monophosphate receptor protein (CRP or CAP) of Escherichia coli to non-specific DNA and to a specific lac recognition sequence has been investigated by circular dichroism (c.d.) spectroscopy. The effect of cAMP and cGMP on the co-operative non-specific binding was also studied. For the non-specific binding in the absence of cAMP a c.d. change (decrease of the intensity of the positive band with a shift of its maximum to longer wavelength) indicates that the DNA undergoes a conformational change upon CRP binding. This change might reflect the formation of the solenoidal coil previously observed by electron microscopy. The amplitude of the c.d. change increases linearly with the degree of saturation of the DNA and does not depend on the size of the clusters of CRP bound. From the variation of the c.d. effect as a function of the ionic strength, the product K omega (K, the intrinsic binding constant and omega, the co-operativity parameter) could be determined. The number of ion pairs involved in complex formation between CRP and DNA was found to be six to seven. Experiments performed with several DNAs, including the alternating polymers poly[d(A-T)] and poly[d(G-C)], demonstrated that the conformational change does not depend on the DNA sequence. However, in the presence of cAMP the c.d. spectrum of the DNA shows only a small variation upon binding CRP. In contrast, in the presence of cGMP the conformational change of the DNA is similar to that observed when non-liganded CRP binds. For the specific lac operon binding, the c.d. change is different from those observed for non-specific binding in the presence or absence of cAMP. These results emphasize the high variability of the DNA structure upon binding the same protein.
J Mol Biol 1987 May 05
PMID:Interaction between the cyclic AMP receptor protein and DNA. Conformational studies. 282 Dec 69

Purified inhibitor of the cyclic AMP-dependent protein kinase (PKI) has been used as a probe to determine if hormone and cyclic AMP-induced activation of the cardiac alkaline triacylglycerol (TG) lipase is mediated through the cAMP-dependent protein kinase. Addition of CAM (cyclic AMP, Mg-ATP, and 3-isobutyl, 1-methylxanthine) to any of the four fractions (homogenate, 10,000 g supernatant, 105,000 g supernatant, or heparin-Sepharose eluate) from heparin perfused heart activated the TG lipase 60% to 110%. Preincubation of these fractions with 33 ng of PKI had no effect on control enzyme activity. Addition of PKI (33 ng) to extracts following CAM activation had little effect on homogenate TG lipase activity, but reduced activities in 10,000 g and 105,000 g supernatant fractions to their respective control levels, and inhibited TG hydrolase activity of activated heparin-Sepharose eluate to 50% below the control activity. If extracts were preincubated with PKI prior to CAM addition, TG lipase activity was reduced to approximately 50% below control levels in all fractions. PKI addition (33 ng) to 105,000 g supernatant obtained from hearts stimulated 60% by epinephrine perfusion reduced activity to 50% below the control level. PKI inhibition of TG lipase activity of 105,000 g supernatant could be reversed by adding 0.5 microgram of catalytic subunit of protein kinase (PKC) to the extract. The inhibition below control levels caused by CAM and PKI indicate that the PKI-PKC complex by itself or in combination with other extract molecules, has an inhibitory effect on the TG lipase.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Cell Cardiol 1987 Jul
PMID:Protein kinase inhibitor blocks the activation of a myocardial triacylglycerol lipase. 282 94

We have isolated a new class of mutations in rpoD, the gene encoding the sigma 70 subunit of Escherichia coli RNA polymerase, that alter the transcription initiation properties of RNA polymerase holoenzyme. The rpoD(Lac) mutations increase expression of the lac operon in the absence of CAP-cAMP, allowing a strain lacking adenyl cyclase to grow on lactose. Four of the six alleles isolated have three- to fivefold increases in the amount of lac mRNA and beta-galactosidase per cell. We show that these four mutations increase transcription initiation from the same promoter used by wild-type RNA polymerase. The mutations were mapped and sequenced. One mutation occurs in the codon for amino acid 389 of the sigma 70 polypeptide. The remaining five mutations are clustered, affecting residues 570, 571 and 575. These five mutations are within or near a proposed helix-turn-helix motif in the C terminus of sigma 70.
J Mol Biol 1988 Sep 05
PMID:Mutations in rpoD, the gene encoding the sigma 70 subunit of Escherichia coli RNA polymerase, that increase expression of the lac operon in the absence of CAP-cAMP. 284 53

A human transient expression system was used to measure the influence of simian virus 40 T antigen and adenovirus E1a proteins on the activation of alpha interferon subtype 1 (IFN-alpha 1) and IFN-beta promoters linked to the reporter chloramphenicol acetyltransferase gene. Large T-antigen production, amplified by expression plasmid replication in transfected 293 cells, was able to trans activate the IFN-beta promoter 5- to 10-fold, increasing both the constitutive and Sendai virus-induced levels of expression. Surprisingly, the previously quiescent transfected IFN-alpha 1 promoter in T-antigen-expressing cells displayed a level of inducibility similar to IFN-beta. The endogenous IFN-alpha 1 gene was also inducible to a limited extent in cells expressing T antigen. A truncated IFN-beta promoter deleted to position -37 relative to the CAP site was neither inducible nor trans activated by T antigen, suggesting that sequences required for efficient induction were also needed for trans activation. Since 293 cells express adenoviral E1a proteins, experiments were also performed in HeLa cells to assess the relative contribution of T antigen and E1a proteins to IFN trans activation. In HeLa cells, T-antigen coexpression increased the constitutive level of IFN-beta and IFN-alpha 1 promoter activity without augmenting relative inducibility. Coexpression of T antigen and E1a proteins did not have a cooperative effect on type 1 IFN expression.
Mol Cell Biol 1988 Aug
PMID:trans activation of type 1 interferon promoters by simian virus 40 T antigen. 285 Apr 92

Digestion of canine and bovine intercalated disks with a calcium-activated protease (CAF) removes the electron-dense material similar to that found at the Z-line and presumably consisting primarily of alpha-actinin. The major filaments exposed by CAF are actin, and the polarity is away from the intercalated disk, as was confirmed by decoration with heavy meromyosin. The length of actin filaments associated with the fascia adherens region at the concave region is 1.2- to 2.2-fold that of actin filaments (I-filaments) in the sarcomere and varies depending on the interdigitation of the membrane at the cell junction. Actin filaments at the intercalated disk seem to be attached (or very close) to the membrane in a direct, rather than looping, manner.
J Ultrastruct Mol Struct Res 1988 Sep
PMID:Polarity and length of actin filaments at the fascia adherens of the cardiac intercalated disk. 285 47

The Escherichia coli lac promoter has been shown to contain an RNA polymerase binding site (P2) that overlaps with, and is shifted 22 base-pairs upstream from the normal lac promoter (P1). In this paper, we provide RNA polymerase protection data obtained in vitro that show that, in the absence of CAP-cAMP, in vitro P2 is the preferred polymerase binding site on the P+ template. In the presence of CAP-cAMP, polymerase binding to P2 is reduced and more polymerase is bound at P1. Two lac P1 "-35 region" mutations, L157 and 4, which increase the homology between this region and the consensus "-10 region" sequence, are both shown to have an increased affinity for polymerase binding at P2. CAP-cAMP is also able to decrease the amount of polymerase bound to P2 and to increase the amount bound to P1 on these mutant promoter fragments. P2 does not initiate transcription efficiently in vivo. Nuclease S1 mapping experiments detect only a low level of transcription from one of the P2 "up" mutations, but no beta-galactosidase synthesis is directed by this mutant. Mutations such as L157 and 4, which alter the P2-10 region, also alter lac P sensitivity to CAP-cAMP in vivo, suggesting that the P2 sequence plays a role in CAP-cAMP regulation of lac P. Possible roles for P2 in vivo are discussed.
J Mol Biol 1985 Oct 05
PMID:Properties of lac P2 in vivo and in vitro. An overlapping RNA polymerase binding site within the lactose promoter. 299 53

Kline et al. (1980) have reported that indole-3-acetic acid (IAA) and four other indole derivatives are able to substitute for cAMP in activating expression of the ara regulon of E. coli. We have examined this phenomenon in detail, utilizing fusions between the structural gene for beta-galactosidase and the promoters for the araBAD, araE, and araFG operons. We confirm that IAA potently stimulates transcription from the araBAD promoter. The effect is highly specific to araBAD, as IAA has no, or only slight, effects on the araE and araFG operons. However, contrary to the results of Kline et al., we find that the action of IAA does not require CAP. Thus, IAA fully stimulates the transcription of araBAD in a strain which bears a complete deletion of the crp gene.
Mol Gen Genet 1985
PMID:The catabolite gene activator protein (CAP) is not required for indole-3-acetic acid to activate transcription of the araBAD operon of Escherichia coli K-12. 299 82


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