Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.1 (S1 nuclease)
3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of 3 beta-amyloid protein precursor (APP) mRNAs (695, 751, and 770) in the cerebral cortex in Alzheimer's disease and other neurodegenerative diseases was analyzed by the S1 nuclease protection assay. We found no significant Alzheimer's disease-specific alteration of APP mRNA expression when compared to the other neurological diseases as controls. Since the expression of this mRNA was not correlated with amyloid deposition, it is possible that gliosis/neuronal loss may secondarily alter APP mRNA expression. However, the current study revealed no significant correlation between them.
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PMID:Cerebral cortical amyloid protein precursor mRNA expression is similar in Alzheimer's disease and other neurodegenerative diseases. 140 96

Streptomyces coelicolor A3(2), lysogenised by the temperature-sensitive cts1 mutant of phi C31, can be synchronously induced into the lytic cycle by heat treatment. A transcription map of 10 kb of the phi C31 early gene cluster was deduced using low-resolution S1 nuclease mapping of RNA prepared 10 min after induction. At least nine early transcripts, early (e)RNAs 1-9, were localised reading exclusively rightwards with respect to the standard physical map of phi C31. The mRNAs were extensively overlapping, frequently initiating at the same place but terminating at different sites, and vice versa. Gene expression during the lytic cycle was tightly regulated; no transcription was observed before induction. Transcription was maximal at 10 min post-induction, and at 20 min, eRNAs 5 and 6 persisted whilst eRNAs 7-9 were severely reduced or absent. The pattern of transcription of the early region is consistent with the simultaneous activation of a large number of promoters and differential termination efficiency.
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PMID:Transcription map of the early region of the Streptomyces bacteriophage phi C31. 145 40

The gene for the beta A4-amyloid precursor protein (APP) consists of 19 exons which code for a typical N- and O-glycosylated transmembrane protein with four extracellular domains followed by the transmembrane domain and a short cytoplasmic domain. The beta A4-amyloid sequence is part of exons 16 and 17. Several APP isoforms can be generated by alternative splicing of exons 7 and 8, encoding domains with homologies to Kunitz-type protease inhibitors and the MRC OX-2 antigen, respectively. The mechanism by which the pathological beta A4 is generated is unknown, it is however a critical event in Alzheimer's disease and is distinct from the normally occurring cleavage and secretion of APPs within the beta A4 sequence. We report here for the first time considerable APP mRNA expression by rat brain microglial cells. In addition we showed by S1 nuclease protection and polymerase chain reaction analysis of reverse transcribed RNA (RT-PCR) that T-lymphocytes, macrophages, and microglial cells expressed a new APP isoform by selection of a novel alternative splice site and exclusion of exon 15 of the APP gene. This leads to a transmembrane, beta A4 sequence containing APP variant, lacking 18 amino acid residues close to the amyloidogenic region. The use of this novel alternative splice site alters the structure of APP in close proximity to the beta A4 region and thus may determine a variant, potentially pathogenic processing of leukocyte-derived APP in brain.
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PMID:Identification and differential expression of a novel alternative splice isoform of the beta A4 amyloid precursor protein (APP) mRNA in leukocytes and brain microglial cells. 158 57

A lysogen of Streptomyces coelicolor A3(2) containing a thermoinducible mutant of the temperate phage phi C31 (phi C31 cts1) was used to obtain synchronous phage development. Filter hybridization experiments indicated a marked reduction in rRNA synthesis after prophage induction. S1 nuclease mapping showed that transcription from each of the four promoters of one rRNA gene set (rrnD) was reduced to approximately the same extent, and that inhibition required protein synthesis. Crude preparations of RNA polymerase from induced lysogens had enhanced transcribing activity for phi C31 DNA which was lost upon further purification. The purified preparations were unimpaired in their ability to transcribe from the rrnD promoters in vitro and apparently unchanged in polypeptide composition. The factor(s) responsible for stimulating phage transcription, and possibly for inhibiting rRNA synthesis, may have been separated from the enzyme during purification.
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PMID:Induction of a phi C31 prophage inhibits rRNA transcription in Streptomyces coelicolor A3(2). 170 39

Using an S1 nuclease protection assay, we have identified a novel "variant" Amyloid Precursor Protein (APP) RNA in human brain which is 3-6-fold more abundant than APP-770, but less abundant than APP-751 or APP-695. This variant, referred to as amyloid precursor-related protein 365 (APRP-365), is not detected in mouse and rat brain RNAs. A 1.6 kilo-basepair cDNA clone corresponding to this variant APP RNA predicts the existence of a 365 amino acid protein that is similar to the amino-terminal end of APP-770 but lacks the beta-amyloid peptide and any hydrophobic transmembrane spanning domains. In a modified polymerase chain reaction (PCR), we used amplification of reverse transcribed mRNA to confirm and extend our S1 observations. Together, the features of APRP-365 suggest that the human variant is a soluble protein containing a Kunitz protease inhibitor domain.
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PMID:A novel species-specific RNA related to alternatively spliced amyloid precursor protein mRNAs. 172 73

We have used an S1 nuclease protection strategy to measure alternatively spliced amyloid precursor protein (APP) mRNAs associated with Alzheimer's disease (AD) to determine whether the expression of either one or more of the transcripts correlate with observed amyloid plaque pathology. Comparison of AD with normal cortex reveals that increasing plaque density parallels an increase in the fraction of APP-695 and a corresponding decrease in APP-770 and 751 mRNA fractions. A specific increase of APP-695, the protease inhibitor-lacking APP RNA form, in those brain regions most involved with amyloid plaque formation, suggests that an imbalance in the protease inhibitor is potentially significant in the disease. These data are consistent with cellular/tissue region-specific regulation of alternative splicing accounting for AD-related changes in the expression of APP mRNA forms.
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PMID:Quantitative measurement of alternatively spliced amyloid precursor protein mRNA expression in Alzheimer's disease and normal brain by S1 nuclease protection analysis. 172 74

Retinoic acid (RA) induced differentiation of SH-SY5Y neuroblastoma cells is associated with more than a tenfold induction of total Alzheimer's disease beta A4 amyloid protein precursor (APP) mRNA as analyzed by Northern blot hybridisation. S1 nuclease protection experiments reveal that the splicing pattern of these differentiated cells is altered in favor of APP695 mRNA, coding for the shortest amyloidogenic beta A4 amyloid precursor protein. Induction of differentiation of SH-SY5Y cells with NGF leads to a fivefold increase of total APP mRNA without change in the splicing pattern. This suggests that RA but not NGF induces factor(s) which are responsible for an APP hnRNA splicing favoring APP695 mRNA.
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PMID:Retinoic acid induced differentiated neuroblastoma cells show increased expression of the beta A4 amyloid gene of Alzheimer's disease and an altered splicing pattern. 220 13

The afsR gene of Streptomyces coelicolor A3(2) complements afsB mutations affecting production of pigmented antibiotics. It also directs pigment production in Streptomyces lividans when carried on a plasmid vector. Nucleotide sequencing of the afsR gene revealed that it codes for a 993-amino acid protein (Mr 105,600) with A- and B-type ATP-binding consensus sequences at its N-terminal portion and two DNA-binding consensus sequences with a helix-turn-helix motif at its C-terminal portion. Each of the N- and C-terminal halves was capable of conferring pigment production, to some extent, in S. lividans, when carried separately on a multicopy plasmid. In addition, expression in trans of the two regions on the same plasmid conferred pigment production to almost the same extent as did the intact afsR gene. Mutations at the two ATP-binding consensus sequences, that were generated by in vitro site-directed mutagenesis, revealed their functional importance. Disruption of the S. coelicolor A3(2) chromosomal afsR gene in either the N- or C-terminal half using phage phi C31 KC515 resulted in significant, but not complete, loss of pigment production. These data suggest that the AfsR protein comprises two domains, viz., an ATP-binding and a DNA-binding domain, each of which could function as a positive regulator for pigment production. These afsR mutants sporulate normally. In addition to an internal promoter, which we previously detected in the middle of the AfsR coding region, S1 nuclease mapping revealed two tandem transcriptional start points, separated by 64 bp, upstream from a putative ATG start codon of the AfsR product.
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PMID:Primary structure of AfsR, a global regulatory protein for secondary metabolite formation in Streptomyces coelicolor A3(2). 225 87

Alzheimer's disease (AD) is associated with the extra-normal accumulation of a 42 amino acid (aa) beta-amyloid peptide (BAP) in amyloid plaques and cerebrovascular deposits. Though BAP is deposited exclusively in brains of AD and Down syndrome patients, the mRNA encoding the putative precursor to BAP is found in the brain and in peripheral tissues. Using an HL 60 cDNA library, we have isolated two Amyloid Peptide Precursor (APP) cDNAs with sequences that code for proteins containing 751 and 770 aa (APP 751 and APP 770). These longer forms of APP encode a novel region of 56 aa which is homologous to the Kunitz domain of serine protease inhibitors which is not found in the 695 aa form (APP 695) isolated from brain (1). We have examined APP expression at the RNA level using Northern blots and S1 nuclease protection studies in which the lengths, distributions and relative abundances of APP RNAs were assayed. We find that brain, WA 17 cells and NG 108-15 cells contain all three forms of APP RNAs while HL 60 cells, TMT3 cells and AB-1 cells contain predominantly the APP 751 and APP 770 RNAs.
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PMID:Isolation and expression of multiple forms of beta amyloid protein precursor cDNAs. 248 24

The A4 amyloid precursor gene of Alzheimer's Disease (PreA4 gene, App gene, PAD gene) gives rise to three different transcripts, which are generated by alternative splicing. The three transcripts are PreA4695, PreA4751 and PreA4770, according to the number of amino-acids in the primary translation product. Previous expression studies did not discriminate between PreA4751 and PreA4770. We have analyzed the distribution of PreA4 transcripts in four cortical brain areas in a way that allows us the selective identification of each transcript. We used a sensitive S1 nuclease protection assay with a probe derived from PreA4770 cDNA. This radiolabeled probe gives rise to three specifically protected DNA fragments, each corresponding to one of the three PreA4 transcripts. These fragments could readily be resolved in a single lane of a denaturing polyacrylamide gel. PreA4 transcripts were quantified by scanning autoradiograms. In younger individuals PreA4695 mRNA is the dominant transcript with 55% (mean values). PreA4770 mRNA is the minor PreA4 transcript with less than 5% and PreA4751 ranges at 40%. The exception is observed in occipital cortex, where PreA4751 (50%) is higher than PreA695 (45%). A different situation was observed in older individuals. In the latter PreA4(695) transcripts are significantly reduced, with the exception of frontal cortex, whereas PreA4770 transcripts show an increase. PreA4751 has a constant level of 45% and becomes the dominant transcript.
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PMID:PreA4 mRNA distribution in brain areas. 257 67


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