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)

Human intercellular adhesion molecule-1 (ICAM-1), a specific ligand for the lymphocyte function-associated Ag-1 (LFA-1), plays an important role in leukocyte-endothelial cell interactions. It is induced by proinflammatory cytokines such as IL-1, TNF-alpha, or IFN-gamma. However, little is known concerning the intracellular regulatory mechanisms which trigger ICAM-1 up-regulation. In order to study potential regulatory elements involved in ICAM-1 induction we have cloned the human ICAM-1 gene and 5 kb of its 5'-regulatory region. The sequence of the cDNA was found to be distributed over seven exons separated by six introns, whereby each of the five extracellular Ig-like domains of ICAM-1 is encoded by its own exon. The upstream sequence harbors a number of sequence motifs implicated in the regulation and expression of eukaryotic genes, including binding sites for the transcription factors SP-1, AP-1, and NF-kB. Primer extension and S1 nuclease analysis revealed two transcription initiation sites 319 bp and 41 bp upstream of the translation start site. Consensus TATA boxes were found at the expected positions about 25 bp upstream of both start sites. Reverse transcriptase polymerase chain reaction showed differential use of the two TATA boxes in A549 and HS913T cells. Both RNA seem to code for the same for of ICAM-1 protein. For regulation studies a 1.3-kb EcoRI/SalI fragment of the 5'-flanking region was used to promote transcription of a linked luciferase reporter gene in transient-transfection assays in A549 and HS913T cells. Treatment of A549 cells with IL-1 or TNF-alpha resulted in a two- or fourfold increase in luciferase activity. Furthermore, a sixfold induction could be achieved after treatment with the phorbol ester PMA. In contrast, agents that increase intracellular cAMP levels did not induce luciferase activity. Northern blot analysis was used to investigate the kinetics of ICAM-1 mRNA synthesis upon induction with TNF-alpha and PMA. These data suggest that the up-regulation of ICAM-1 by cytokines occurs at least partly at the transcriptional level. Deletion analysis of the 1.3-kb fragment of the 5'-flanking region revealed sequences responsible for promotion and inhibition of transcription. In particular, two functionally distinct regions have been characterized: a short fragment containing an NF-kB binding site has been shown to function as an activator, followed immediately downstream by a sequence acting as a silencer element. Therefore, ICAM-1 gene expression seems to be modulated by multiple cis-acting elements.
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PMID:Cloning of the human gene for intercellular adhesion molecule 1 and analysis of its 5'-regulatory region. Induction by cytokines and phorbol ester. 168 Sep 19

We have cloned the human perforin (P1) gene and sequenced 6.2-kb genomic DNA, containing 1.4-kb 5'-flanking region, the 5' untranslated region, the complete coding region and the beginning of the 3' untranslated region. The P1 gene including at least 95-bp 3' untranslated region is organized in only three exons: the first exon (97 bp) contains all but four nucleotides of the 5' untranslated region and was determined by primer extension and S1 nuclease mapping. This exon is separated by 1.7 kb from the second exon containing the remaining (4 bp) 5' untranslated region, the leader peptide and the N-terminal region of P1 up to--but not including--the C9 homologous region. The third exon is separated by a 1.2-kb intron and contains the remainder of the molecule, including at least 90 bp of the 3' untranslated region. This simple gene organization differs from that of the more complicated C9 gene. Because of the unusual intron in the 5' untranslated sequence the transcription initiation (cap) site is located almost 1.8 kb upstream of the ATG start signal. The more immediate 5' flanking sequence contains a CCAAT and GC box but lacks other known promoter elements. Instead, we find three different sequence repeats. One of them, a hexanucleotide sequence with the consensus GCCCTG of unknown significance occurs 19 times within a stretch of 240 bp. Further upstream we localized sequences homologous to the following enhancer and promoter elements: c-fos proto-oncogene, IFN-gamma and phorbol ester response elements, five cAMP response elements, and three motifs corresponding to general inducer elements. In addition, a sequence conserved in the 5'-flanking region of several T cell genes was identified. The 5' flanking regions of P1. CCP1 (granzyme B) and CCP2 (granzyme C) (kindly provided by Dr. Bleackley) contain as only significant homology cAMP response elements. These findings are consistent with a tight control and regulation of P1, which appears to be distinct from that of granzymes.
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PMID:Structure of the human perforin gene. A simple gene organization with interesting potential regulatory sequences. 248 Mar 91

Murine complement protein H is encoded by a 100-kb gene on chromosome 1. A 3.2-kb fragment of the 5' flanking region of the H gene was sequenced, and two transcription start sites for this gene were identified by RNase protection and S1 nuclease analyses, each of which had upstream TATA and CAAT boxes. This region shares sequence homology with known regulatory elements, including the SV40 enhancer consensus, the Sp1 binding site, and two glucocorticoid-responsive core elements (GRE). Tissue and cell-line specificity has been examined by Northern analysis, and the 4.4-kb full-length H messenger RNA was identified in liver, kidney, spleen, thymus, liver cell line 1469, and L cells. IFN-gamma did not induce H mRNA expression in the macrophage cell line P388D.1 but had a positive effect on both the mRNA and protein levels of H in L cells. PMA, LPS, and vitamin D did not increase H mRNA levels in L cells. Pursuant to the discovery of two GRE in the 5' regulatory region of the H gene, we examined the effects of glucocorticoids on H mRNA expression. Dexamethasone (10(-7) M) was found to increase markedly the levels of H mRNA and protein after 24 h of incubation, and the effect on the mRNA was detectable by 30 min. The fact that H is a down-regulator of complement activation is consistent with the known immunosuppressive role of glucocorticoids. To our knowledge, this is the first time that dexamethasone has been shown to increase the levels of a complement protein.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Analysis of complement factor H mRNA expression: dexamethasone and IFN-gamma increase the level of H in L cells. 253 12

We produced the T cell hybridoma D9C1.12.17 by fusing an IL-4-producing T cell clone D9.1Hi with the AKR thymoma BW5147. The resulting hybridoma produced IL-2 as well as IL-4 even though none of the parental cells produced IL-2 after stimulation with Con A. The production of IL-2 was confirmed at the mRNA level by using an S1 nuclease protection assay. Further analysis indicated that Con A-induced IL-2 production was a common phenomenon among T cell hybridomas derived from this fusion. Although BW5147 does not produce detectable lymphokines after Con A stimulation, this line was able to produce IL-2, granulocyte-macrophage colony stimulating factor, and small amounts of IL-3 and IFN-gamma when stimulated with calcium ionophore and phorbol ester. The latter agents are thought to mimic the activating signal(s) delivered through the Ag:MHC TCR. This observation indicates that BW5147 has the ability to produce lymphokines but may lack component(s) which couple the extracellular signal to lymphokine production, and suggests that in T cell hybridomas, part of the spectrum of lymphokines produced may be contributed by BW5147.
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PMID:The AKR thymoma BW5147 is able to produce lymphokines when stimulated with calcium ionophore and phorbol ester. 312 29

FS-4 fibroblasts were found to produce 37-kDa HLA class I heavy chain in response to IFN-gamma or TNF in a time- and dose-dependent fashion, and a synergism between IFN-gamma and TNF was observed. Immunoprecipitation of IFN-gamma- or TNF-induced FS-4 cell culture supernatants by mAb A1.4 revealed an additional 33-kDa protein in association with the 37-kDa heavy chain. The 33-kDa protein appeared to be expressed in a 38-kDa form on the membrane of FS-4 cells induced by IFN-gamma or TNF, as A1.4 immunoprecipitated the 38-kDa band in association with the 44-kDa transmembrane HLA class I heavy chain. Release of the 37-kDa heavy chain could well be due to an alternative RNA splicing with the deletion of exon 5 encoding the hydrophobic transmembrane region of membrane-anchored HLA class I heavy chain. Northern blot analysis and S1 nuclease protection assay suggested the existence of HLA class I heavy chain mRNA lacking exon 5 in IFN-gamma- or TNF-induced FS-4 cells. Southern blot analysis on the products of reverse transcription-polymerase chain reaction amplification from cytoplasmic RNA confirmed induction of alternative splicing by these cytokines. Our results suggest that cytokine-induced production of soluble HLA class I molecules may play important roles in the regulation of T cell interaction with antigen-presenting cells.
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PMID:Alternative splicing of HLA class I transcripts induced by IFN-gamma and TNF in fibroblasts: release of soluble HLA class I heavy chain and an associate protein. 770 5

IFN-gamma is a cytokine that regulates various functions of the immune system. The major producers of IFN-gamma are T cells and NK cells. 2B4 is a novel activating receptor expressed on all human NK cells, a subset of CD8+ T cells, monocytes and basophils. Activation of human NK cells through surface 2B4 enhances NK cell cytolytic function and secretion of IFN-gamma. We have examined the regulation of IFN-gamma production by the human NK cell line YT upon activation through surface 2B4. Our data indicate that ligation of surface 2B4 by mAb C1.7, that specifically recognizes 2B4, induces transcriptional activation of IFN-gamma. Partial inhibition of transcription did not prevent the transcriptional upregulation of IFN-gamma. S1 nuclease protection analysis indicated that transcriptional activation as well as mRNA stability may account for the increased production of IFN-gamma by human NK cells following 2B4 stimulation.
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PMID:Regulation of IFN-gamma production following 2B4 activation in human NK cells. 1112 47