Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tau is a highly conserved protein during evolution. However, polymerization of tau into paired helical filaments, a characteristic of Alzheimer disease is unique to humans and has not been seen in animals. The cause of this phenomenon is not known. The cDNA-derived amino acid sequences of bovine and human tau are highly homologous. In this study we show that despite the high homology there are marked differences between the immunoreactivities of human and bovine tau. The four antibodies employed in this study were the monoclonal Tau-1 to the bovine protein, two polyclonal anti-bovine tau 92e and 111e and a polyclonal anti-human tau 113e. The monoclonal antibody Tau-1, the epitope of which lies in the amino acid residues 196-215 of bovine tau and residues 189-207 of human tau differing by a single amino acid, a glycine at position 196 in bovine protein with a proline at position 189 in human protein, reacts 2.3 +/- 0.5 times better with bovine tau than with human tau. Both polyclonal antibodies against bovine tau, 92e and 111e react 25 +/- 7 and 45 +/- 17 folds, respectively, better with bovine tau than human tau, whereas the polyclonal antibody 113e to a human tau peptide does not cross-react with bovine tau. The differences in cross-reactivity that are probably due to differences in conformation of tau from the two species were found using both cytosolic extracts and tau isolated from human and bovine brains.(ABSTRACT TRUNCATED AT 250 WORDS)
Brain Res Mol Brain Res 1995 Jul
PMID:Bovine and human tau, highly homologous but less crossreactive: implications for Alzheimer disease. 747 29

Senile plaques, a hallmark of Alzheimer's disease (AD), contain amyloid beta-peptide (A beta), which is generated from the larger amyloid beta protein precursor (APP). In addition to APP, several APP-related proteins have been recently identified in different organisms, including Drosophila amyloid precursor protein-like protein (APPL). Deficiency of APPL causes behavioral deficits in Drosophila, implicating a role in brain function. Moreover, mouse and human cDNA clones encoding amyloid precursor-like proteins (APLP1 and APLP2) have been identified and exhibit extensive sequence similarity to the APPL and APP genes. To define the potential role of APLP in the mammalian brain, we sought to directly localize APLP1 within the complex cortical synaptic structure. We focused on the postsynaptic density (PSD), which appears to be central to synaptic function. We now report that the 90 kDa APLP1, the first known APLP, is localized to the PSD from rat and human cerebral cortex. APLP1 increased during cortical synaptic development, suggesting a role in synaptogenesis or synaptic maturation. In contrast, APP was predominantly expressed in the synaptic membrane fraction, but was barely detectable in the PSD, including different subcellular distributions of APP and APLP1. Our observations raise the possibility that APLP1, a homologue of APPL, which appears to be necessary for normal behavior in Drosophila, participates in brain synaptic function in mammals.
Brain Res Mol Brain Res 1995 Aug
PMID:Selective localization of amyloid precursor-like protein 1 in the cerebral cortex postsynaptic density. 749 61

Abnormalities in gene regulation of the beta-amyloid precursor protein (beta APP) might be an important factor in the neuropathology of Alzheimer's disease. We analyzed the effects of nerve growth factor (NGF), basic fibroblast growth factor (bFGF), phorbol 12-myristate 13-acetate (PMA), interleukin-1 (IL-1) and retinoic acid (RA) on promoter activity of the beta APP gene. To investigate the effect of these factors on promoter activity, we used two fusion plasmids which contain sequences of -489 and -415 base pairs (bp), respectively, from the transcription start site of the beta APP gene. The truncated regions of the promoter wer linked upstream to a reporter gene, chloramphenicol acetyl transferase (CAT). Promoter activity was tested by transient transfection of fusion plasmids in PC12 cells using the electroporation method (960 microF at 350 V). We report that the treatment of PC12 cells with either NGF, bFGF, PMA, IL-1 or RA stimulated the activity of the beta APP promoter. The treatment of cells with either NGF or bFGF resulted in a higher degree of stimulation in the basal level of promoter activity than when cells were treated with either PMA, IL-1 or RA. The deletion of sequences between -489 to -416 bp had no significant effect on promoter activity. The treatment of cells with these factors for a duration of 4 days prior to transfection with the plasmids is necessary for the stimulatory effect. The cells that were only treated with any of these factors after transfection showed no significant change in the basal level of promoter activity. We conclude that certain growth factors and a cytokine could enhance the basal level of promoter activity of the beta APP gene, suggesting a possible participation of a growth-factor(s)-mediated transcription element in the control of gene expression of beta APP.
Brain Res Mol Brain Res 1995 Sep
PMID:Promoter activity of the gene encoding the beta-amyloid precursor protein is up-regulated by growth factors, phorbol ester, retinoic acid and interleukin-1. 750 Aug 34

The expression of L-beta A4 amyloid precursor protein (L-APP) mRNA, which is a splicing product excluding exon 15 of the APP gene, was investigated in various tissues of adult rats by a polymerase chain reaction analysis of reverse-transcribed RNA (RT-PCR). L-APP mRNA was ubiquitously expressed in all the examined tissues including the liver, kidney, heart, skeletal muscle, spleen, thymus, adrenal, stomach, submandibular gland, testis and ovary, except for the central nervous system (CNS) tissues such as the brain and spinal cord. The DNA sequence analysis of the RT-PCR products from adult rat liver showed an L-APP cDNA form, in which exon 14 was spliced from exon 14 to exon 16, and exon 15 of the APP gene was excluded. In addition, regarding as the brain and liver, L-APP mRNA expression was examined during the development of the embryonic stage. In the brain, no L-APP mRNA expression was detected even in the embryonic stage, whereas L-APP mRNA expression of the liver was still found in the embryonic stage. These results suggest that the splicing event excluding exon 15, which is exactly adjacent to exon 16 and exon 17 encoding the beta A4 protein, would probably occur very rarely in the CNS and that the splicing of L-APP might already be regulated in the embryonic stage.
Brain Res Mol Brain Res 1993 Nov
PMID:Alzheimer's amyloid precursor protein mRNA without exon 15 is ubiquitously expressed except in the rat central nervous system. 750 74

Transcription of the gene encoding amyloid precursor protein (APP) varies in a cell-specific and developmentally regulated manner. The 5' region of this gene possesses a high frequency of CpG dinucleotides as well as copies of a GC-rich sequence, a potential trans factor binding element. These findings raise the possibility that DNA cytosine methylation could participate in the regulation of APP gene expression. We examined APP mRNA/18S rRNA ratio in three neural cell lines (N18TG2, SN6, SN17) cultured in 5-azacytidine (5-AZA), an inhibitor of maintenance methylase which results in loss of cytosine methylation in proliferating cells. Culture in 5-AZA globally reduced methylation in genomic DNA as assessed by an increase in HpaII restriction sites, reduced cytosine methylation in the APP gene as assessed by Southern blotting of HpaII digests, and increased APP mRNA steady state abundance in all studied cell lines. Cell lines re-acquired APP gene methylation 48 h after removal of 5-AZA from media. These results indicate that in vitro alteration of DNA methylation can affect APP gene expression, and suggest that the APP gene in neuronal cell lines may be rapidly inactivated in vitro, perhaps to neutralize its potential toxicity.
Brain Res Mol Brain Res 1994 Jul
PMID:Amyloid precursor protein gene expression in neural cell lines: influence of DNA cytosine methylation. 752 12

Based on a suspected role of the immune system in the pathophysiology of Alzheimer's disease (AD) and the new discoveries of neuroimmune networks, the investigation of certain neuroimmune markers was performed in AD patients, healthy controls, and disease controls. In agreement with our previous immunological research on AD, the assessment of additional immune parameters revealed abnormalities of both cellular and humoral immunity in several AD patients. These include: 1. Enhanced production of cytokines, such as interleukin-1 (IL-1), interleukin-2 (IL-2), and interleukin-6 (IL-6); 2. Increase plasma level of CD8-positive lymphocyte derived soluble CD8 (sCD8) antigen; and 3. Increased incidence of autoantibodies to brain myelin basic protein (MBP) and thymic cells. As analyzed by flow cytometry and enzyme immunoassay, the peripheral blood immunocytes from AD patients showed a significant increase in the expression of the brain-derived S-100 protein. In the cell proliferation assay, the blood immunocytes from healthy subjects responded to stimulation with beta-amyloid protein (beta AP), but this response was absent in AD patients. The initial results of our research suggest that the studies of specific markers of the neuroimmune axis may be potentially important for the new development of diagnostic and therapeutic strategies for AD.
Mol Neurobiol
PMID:Studies of neuroimmune markers in Alzheimer's disease. 753 89

The beta-amyloid peptide (beta AP), a 39 to 43 residue peptide, is the major component of Alzheimer plaques. Using circular dichroism spectroscopy, titration calorimetry, and analytical ultracentrifugation we have analyzed the self-association of beta AP(1-40) in aqueous solution and the binding of beta AP(1-40) to negatively charged lipid vesicles. The CD spectra of both aggregation and membrane binding are characterized by an isodichroic point at 212 nm, indicating a simple two-state equilibrium for both cases. In aqueous solution beta AP(1-40) exhibits a reversible, concentration-dependent random coil<-->beta-structure transition which can be described by a cooperative aggregation model with an association constant of s = 1.05 x 10(4)M-1 and a nucleation parameter of sigma = 0.012. A similar conformational change is observed upon addition of lipid. At a given peptide concentration, the addition of negatively charged, small unilamellar vesicles also induces a conformational change from a random coil conformation to a conformation with 40 to 60% beta-structure. The binding isotherm can be measured with high sensitivity titration calorimetry. It is approximately linear in the initial binding phase and exhibits an apparent saturation behaviour. The apparent binding constant decreases with concentration from Kapp approximately 2100 M-1 at low concentration to 700 M-1 at the highest concentration measured. Peptide penetration into the lipid membrane and peptide aggregation at the membrane surface are proposed as possible mechanisms to explain the lipid-induced random coil<-->beta-structure transition.
J Mol Biol 1995 Oct 06
PMID:Self-association of beta-amyloid peptide (1-40) in solution and binding to lipid membranes. 756 79

1. The amyloid precursor protein (APP) is widely distributed among eukaryotic cells, however, its precise role in cellular functioning is not fully clarified. APP is glycoprotein membrane constituent and it may facilitate membrane associated functions. 2. The aim of the present study was to examine the possibility that APP may play a role in mediating cellular trophic responses. The methods made use of an antisense oligonucleotide that was prepared to the 5' terminus of APP and shown specifically to reduce the level of APP isoforms. 3. In sequential mixing experiments it was observed that the APP antisense oligonucleotide did not significantly modify the trophic response of PC12 cells pretreated with nerve growth factor (NGF). However, pretreatment of cells with the antisense oligonucleotide diminished NGF-induced increases in cellular size and neurite length. 4. These observations suggest that APP may play a role in modulating the trophic response. The combined use of APP antisense oligonucleotides and neurotrophic agents may find clinical utility in the treatment of Alzheimer-type dementia since it is known that NGF normally causes increases in APP levels.
Cell Mol Neurobiol 1994 Oct
PMID:Modulation of the PC12 cell response to nerve growth factor by antisense oligonucleotide to amyloid precursor protein. 762 5

The repressor gene, c, is required for maintenance of lysogeny in the Streptomyces phage phi C31. The c gene expresses three in-frame N-terminally different protein isoforms at least one of which is thought to bind to a 17bp highly conserved inverted repeat (CIR) sequence found at 18 (or more) loci throughout the phi C31 genome. Here we present evidence that one of these loci, CIR6, and its interaction with the products of the repressor gene are critical in the control of the lytic pathway in phi C31. To the right of CIR6, according to the standard map of phi C31, an 'immediate-early' promoter, ap1, was discovered after insertion of a fragment containing CIR6 upstream of a promoterless kanamycin-resistance gene, aphII, to form pCIA2. pCIA2 conferred kanamycin resistance upon Streptomyces coelicolor A3(2) but not upon a phi C31 lysogen of S. coelicolor. Operator-constitutive (Oc) mutants of pCIA2 were isolated and the mutations lay in CIR6, i.e. CIR6:G14T and CIR6:C2A. Primer extension analysis of RNA prepared from an induced, temperature-sensitive lysogen of S. coelicolor localized a mRNA 5' endpoint 21 bp to the right of CIR6. The importance of the ap1/CIR6 region in the regulation of lytic growth was demonstrated by the analysis of a virulent mutant, phi C31 vir1, capable of forming plaques on an S. coelicolor phi C31 lysogen. phi C31vir1 contained a DNA inversion with the breakpoints lying within the integrase gene (which lies approximately 7 kbp to the right of CIR6) and in the essential early region between CIR6 and the -10 sequence for ap1. The separation of ap1 from its operator was thought to be the basis for the virulent phenotype in phi C31 vir1. Band-shift assays and DNase I footprinting experiments using purified 42 kDa repressor isoform confirmed that CIRs 5 and 6 were indeed the targets for binding of this protein. The 42 kDa repressor bound to CIR6 with higher affinity than to CIR5 in spite of their identical core sequences. Repressor bound at CIR6 facilitated binding at CIR5. The high-affinity binding to CIR6 was abolished with the Oc mutant, CIR6:G14T. Hydroxyl radical footprinting and dimethyl sulphate methylation protection of the 42 kDa repressor-CIR6 interaction suggested that the protein bound in the major groove and to one face of the DNA.
Mol Microbiol 1995 Apr
PMID:Control of lytic development in the Streptomyces temperate phage phi C31. 765 Nov 31

The crystal structure of rat anionic trypsin D189G/G226D has been determined in complexes with each of the protein inhibitors APPI (amyloid beta-protein precursor inhibitor domain) and BPTI (bovine pancreatic trypsin inhibitor) at resolutions of 2.5 A and 2.1 A, respectively. Comparisons with the structure of the bovine trypsin-BPTI complex show that the enzyme-inhibitor interactions in rat trypsin are dominated to a much greater degree by attractive and repulsive electrostatic forces. Decreased structural complementarity in the flanking regions of the interface formed with BPTI is reflected in significantly weaker inhibition relative to bovine trypsin. The primary active site loop of BPTI adopts slightly different conformations when bound to rat and cow trypsins, reflecting a broader entrance to the binding pocket in the former. Tight complementarity of each loop conformer to the respective active sites then gives rise to significantly different overall orientations of the inhibitor when bound to the two enzymes. The crystal structures of trypsin bound to these protein inhibitors are excellent models of the Michaelis complexes, which permit visualization of substrate interactions both N and C-terminal to the cleaved bond, while maintaining identical reaction chemistry. They will be uniquely useful to the structure-function analysis of variant rat trypsin enzymes.
J Mol Biol 1993 Apr 05
PMID:Crystal structures of rat anionic trypsin complexed with the protein inhibitors APPI and BPTI. 768 59


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