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

In Neurospora crassa the qa-2 gene, which encodes catabolic dehydroquinase, is under positive control exerted by the inducer quinic acid and an activator protein encoded in the closely linked qa-1 gene. In order to determine if this regulatory mechanism is maintained when the qa-2 gene is cloned on a recombinant plasmid and expressed in Escherichia coli, molecular cloning experiments have been performed using DNA isolated from a qa-1+ (inducible), a qa-1C (constitutive) and two qa-1 (non-inducible) strains of N. crassa. The results demonstrate that the level of expression of the qa-2 gene in E. coli is completely independent of the mutational state of the qa-1 gene. Moreover, the level of expression of the cloned qa-2 gene was unaffected by either an intracellularly produced inducer of catabolic dehydroquinase or by the general procaryotic positive effector, the CAP factor. The weight of evidence thus supports the conclusion that transcription of the N. crassa qa-2 gene in E. coli does not require the qa-1 activator protein and thus is not controlled by the same mecahnism which functions in N. crassa.
Mol Gen Genet 1979 Apr 17
PMID:Constitutive expression in Escherichia coli of the Neurospora crassa structural gene encoding the inducible enzyme catabolic dehydroquinase. 15 1

Recent results with Neurospora crassa show that one protein (S-5, mol wt 52,000) associated with the mitochondrial (mit) small ribosomal subunit is translated within the mitochondria (Lambowitz et al. 1976. J. Mol. Biol. 107:223-253). In the present work, Neurospora mit ribosomal proteins were analyzed by two-dimensional gel electrophoresis using a modification of the gel system of Mets and Bogorad. The results show that S-5 is present in near stoichiometric concentrations in high salt (0.5 MKCl)-washed mit small subunits from wild-type strains. S-5 is among the most basic mit ribosomal proteins (pI greater than 10) and has a high affinity for RNA under the conditions of the urea-containing gel buffers. The role of S-5 in mit ribosome assembly was investigated by an indirect method, making use of chloramphenicol to specifically inhibit mit protein synthesis. Chloramphenicol was found to rapidly inhibit the assembly of mit small subunits leading to the formation of CAP-30S particles which sediment slightly behind mature small subunits (LaPolla and Lambowitz. 1977. J. Mol. 116: 189-205). Two-dimensional gel analysis shows that the more slowly sedimentaing CAP-30S particles are deficient in S-5 and in several other proteins, whereas these proteins are present in normal concentrations in mature small subunits from the same cells. Because S-5 is the only mit ribosomal protein whose synthesis is directly inhibited by chloramphenicol, the results tentatively suggest that S-5 plays a role in the assembly of mit small subunits. In addition, the results are consistent with the idea that S-5 stabilizes the binding of several other mit small subunit proteins. Two-dimensional gel electrophoresis was used to examine mit ribosomal proteins from [poky] and six additional extra-nuclear mutants with defects in the assembly of mit small subunits. The electrophoretic mobility of S-5 is not detectably altered in any of the mutants. However, [poky] mit small subunits are deficient in S-5 and also contain several other proteins in abnormally low or high concentrations. These and other results are consistent with a defect in a mit ribosomal constituent in [poky].
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PMID:Mitochondrial ribosome assembly in Neurospora. Two-dimensional gel electrophoretic analysis of mitochondrial ribosomal proteins. 15 27

A relationship between serine-induced growth sensitivity and the cAMP-CAP complex is established. Mutants of Escherichia coli K 12 deficient either in the cya or crp gene function exhibit a resistant phenotype on serine media although they harbor a relA allele normally leading to sensitivity toward serine. The presence of a crp allele in a cya delta relA background restores the sensitivity phenotype, while the analysis of serine resistant mutants selected from a crp cya delta relA strain shows that the mutation leading to resistance is located at, or very near, the crp gene, giving a more or less Crp- phenotype. In addition crp cya delta relA strains excrete large quantities of 2-ketobutyrate when grown on glucose M63 medium. This excretion is unambiguously linked to the presence of the crp allele and is correlated with an enhanced threonine deaminase activity. Besides, the complex regulation exerted on the acetolactate synthase activities is discussed.
Mol Gen Genet 1979 Nov
PMID:Involvement of cyclic AMP and its receptor protein in the sensitivity of Escherichia coli K 12 toward serine: excretion of 2-ketobutyrate, a precursor of isoleucine. 23 Apr 7

A fifth cytoplasmic mutation (capr 1) obtained in Podospora anserina is described. In addition to chloramphenicol resistance it confers a strong deficiency in cytochrome aa3 and impairs the germination of ascospores. Genetic analysis shows: 1) strict maternal inheritance of (capr 1) allele; 2) selection against the (capr 1) allele as well in sexual crosses as during vegetative growth; 3) complete reversion of this selection by even low concentration of CAP. On the basis of their cytoplasmic inheritance and altered cytochrome spectra the five cytoplasmic mutations are assumed to be mitochondrial. Analysis of crosses between them allows to class them in 3 loci, 2 of which being closely linked.
Mol Gen Genet 1977 May 20
PMID:Mitochondrial genes in Podospora anserina: recombination and linkage. 88 68

The regulation of open complex formation at the Escherichia coli galactose operon promoters by galactose repressor and catabolite activator protein/cyclic AMP (CAP/cAMP) was investigated in DNA-binding and kinetic experiments performed in vitro. We found that gal repressor and CAP/cAMP bind to the gal regulatory region independently, resulting in simultaneous occupancy of the two gal operators and the CAP/cAMP binding site. Both CAP/cAMP and gal repressor altered the partitioning of RNA polymerase between the two overlapping gal promoters. Open complexes formed in the absence of added regulatory proteins were partitioned between gal P1 and P2 with occupancies of 25% and 75%, respectively. CAP/cAMP caused open complexes to be formed nearly exclusively at P1 (98% occupancy). gal repressor caused a co-ordinated, but incomplete, switch in promoter partitioning from P1 to P2 in both the absence and presence of CAP/cAMP. We measured the kinetic constants governing open complex formation and decay at the gal promoters in the absence and presence of gal repressor and CAP/cAMP. CAP/cAMP had the largest effect on the kinetics of open complex formation, resulting in a 30-fold increase in the apparent binding constant. We conclude that the regulation of open complex formation at the gal promoters does not result from competition between gal repressor, CAP/cAMP and RNA polymerase for binding at the gal operon regulatory region, but instead results from the interactions of the three proteins during the formation of a nucleoprotein complex on the gal DNA fragment. Finally, we present a kinetic model for the regulation of open complex formation at the gal operon.
J Mol Biol 1992 Mar 05
PMID:Regulation of open complex formation at the Escherichia coli galactose operon promoters. Simultaneous interaction of RNA polymerase, gal repressor and CAP/cAMP. 131 5

The pts operon of Escherichia coli is composed of the ptsH, ptsI and crr genes coding for three proteins central to the phosphoenolpyruvate dependent phosphotransferase system (PTS), the HPr, enzyme I and EIIIGlc proteins, respectively. We previously showed that transcription from the promoter region located upstream from the pts operon is regulated by two control circuits, which can occur independently from each other. Transcription of the pts operon is (1) stimulated by the CAP-cAMP complex and (2) enhanced during growth on glucose, a PTS substrate. The DNA regions involved in regulation of the expression of the pts operon have been identified. Two promoters, P0 and P1, separated by 100 bp are located upstream from the pts operon. In these promoter regions, we identified two sequences showing similarity with the consensus of CAP-binding sites, CAPa located near P0 and CAPb located in the -35 region of P1. In vivo experiments showed that binding of CAP-cAMP at the CAPa site stimulates transcription from the P0 promoter. The binding sites of CAP-cAMP and/or RNA-polymerase on a DNA fragment containing both P0 and P1 promoters as well as both CAPa and CAPb sites were examined by the technique of DNase I footprinting. These in vitro experiments suggested that CAP-cAMP binding at the CAPb site might also play a role in regulation of the pts operon expression. In addition, we showed that the DNA region carrying the CAPa site is important for regulation by glucose. We finally propose that the expression of the pts operon is controlled by two alternative positive regulatory mechanisms, which are designed to allow activation of the pts operon under a great variety of growth conditions.
J Mol Biol 1992 Aug 05
PMID:Positive regulation of the expression of the Escherichia coli pts operon. Identification of the regulatory regions. 132 22

The adenylyl cyclases of both Saccharomyces cerevisiae and Schizosaccharomyces pombe are associated with related proteins named CAP. In S. cerevisiae, CAP is required for cellular responses mediated by the RAS/cyclic AMP pathway. Both yeast CAPs appear to be bifunctional proteins: the N-terminal domains are required for the proper function of adenylyl cyclase, while loss of the C-terminal domains results in morphological and nutritional defects that appear to be unrelated to the cAMP pathways. Expression of either yeast CAP in the heterologous yeast suppresses phenotypes associated with loss of the C-terminal domain of the endogenous CAP but does not suppress loss of the N-terminal domain. On the basis of the homology between the two yeast CAP proteins, we have designed degenerate oligonucleotides that we used to detect, by the polymerase chain reaction method, a human cDNA fragment encoding a CAP-related peptide. Using the polymerase chain reaction fragment as a probe, we isolated a human cDNA clone encoding a 475-amino-acid protein that is homologous to the yeast CAP proteins. Expression of the human CAP protein in S. cerevisiae suppresses the phenotypes associated with loss of the C-terminal domain of CAP but does not suppress phenotypes associated with loss of the N-terminal domain. Thus, CAP proteins have been structurally and, to some extent, functionally conserved in evolution between yeasts and mammals.
Mol Cell Biol 1992 Nov
PMID:Identification of a human cDNA encoding a protein that is structurally and functionally related to the yeast adenylyl cyclase-associated CAP proteins. 140 78

We have identified, cloned, and studied a gene, cap, encoding a protein that is associated with adenylyl cyclase in the fission yeast Schizosaccharomyces pombe. This protein shares significant sequence homology with the adenylyl cyclase-associated CAP protein in the yeast Saccharomyces cerevisiae. CAP is a bifunctional protein; the N-terminal domain appears to be involved in cellular responsiveness to RAS, whereas loss of the C-terminal portion is associated with morphological and nutritional defects. S. pombe cap can suppress phenotypes associated with deletion of the C-terminal CAP domain in S. cerevisiae but does not suppress phenotypes associated with deletion of the N-terminal domain. Analysis of cap disruptants also mapped the function of cap to two domains. The functional loss of the C-terminal region of S. pombe cap results in abnormal cellular morphology, slow growth, and failure to grow at 37 degrees C. Increases in mating and sporulation were observed when the entire gene was disrupted. Overproduction of both cap and adenylyl cyclase results in highly elongated large cells that are sterile and have measurably higher levels of adenylyl cyclase activity. Our results indicate that cap is required for the proper function of S. pombe adenylyl cyclase but that the C-terminal domain of cap has other functions that are shared with the C-terminal domain of S. cerevisiae CAP.
Mol Biol Cell 1992 Feb
PMID:Genetic and biochemical analysis of the adenylyl cyclase-associated protein, cap, in Schizosaccharomyces pombe. 155 Sep 59

Appropriately phased DNA bending sequences replacing the CAP binding site upstream from the lac promoter increase by roughly tenfold the rate of specific transcription initiation from a superhelical promoter template in vitro; promoter occlusion results from polymerase binding to the upstream (dA)n.(dT)n tracts, but this phenomenon is not responsible for the observed phase-dependent transcriptional activity. The rates of open complex formation at both P1 and P2 promoters respond in a similar phase-dependent way to the synthetic curved DNA sequences.
J Mol Biol 1991 May 20
PMID:Synthetic DNA bending sequences increase the rate of in vitro transcription initiation at the Escherichia coli lac promoter. 164 11

In this study we determined the activity of the rat luteinising hormone-beta gene promoter in a heterologous rat pituitary cell line (GH3 cells). 1.7 kb of LH-beta 5' flanking sequence and the first 5 bp of the 5' untranslated region were ligated to the chloramphenicol acetyltransferase (CAT) receptor gene (LH-beta-CAT) and transiently transfected by calcium phosphate precipitation into subconfluent cultures of GH3 cells. Basal low-level CAT activity was only detected in GH3 cells, being absent in two non-pituitary cell lines (BeWo and HeLa) RNase analysis revealed that mRNA from transfected GH3 cells protected a fragment of labelled antisense probe of correct size for transcription initiation from the LH-beta CAP site, confirming that promoter activity reflected correctly initiated LH-beta-CAT fusion gene transcripts. CAT activity was consistently induced by an average of 3-5-fold from the full-length 1.7 kb promoter, in a dose- and time-dependent manner, by forskolin, dibutyryl cAMP, and 8-bromo cAMP implying presence of a cAMP-responsive cis-acting domain in the LH-beta promoter region. Transfection of deletion mutants delta-615-CAT, delta-385-CAT and delta-250-CAT each reduced forskolin inducibility to 1.7-fold but did not abolish induction completely suggesting a domain between -1.7 and -0.6 kb contained a cAMP-responsive element(s) (CRE). Further deletion of LH-beta 5' flanking sequences to delta-85-CAT restored forskolin induction to wild-type levels (3-5-fold), suggesting the presence of a weak inhibitory element between -600 and -85 kb, and a cAMP-responsive domain in the proximal promoter region. The LH-beta promoter does not contain perfect tandem repeat palindromic CRE DNA sequences, though there are several octanucleotide sequences differing by only 1 bp from AP-2 binding sites, the consensus CRE, and the vasointestinal peptide gene CRE. Although these data suggest that the LH-beta gene is cAMP responsive this is likely mediated by several and complex protein interactions with multiple DNA sequences in the proximal and distal LH-beta promoter enhancer.
Mol Cell Endocrinol 1991 Sep
PMID:Expression of luteinising hormone-beta subunit chloramphenicol acetyltransferase (LH-beta-CAT) fusion gene in rat pituitary cells: induction by cyclic 3'-adenosine monophosphate (cAMP). 165 45


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