Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The NGFI-A gene encodes a "zinc-finger" protein that is rapidly induced by nerve growth factor (NGF) in PC12 rat pheochromocytoma cells. The complete exon/intron organization and nucleotide sequence of the rat NGFI-A gene have been determined. The gene spans 3789 nucleotides (nt) and is interrupted by a single intron at nt 588. All three zinc-finger DNA-binding domains are contiguously coded for within the 3' exon; this is in contrast to the structure described by others for the Xenopus laevis transcription factor TFIIIA gene. To analyze the transcription of this gene, we have determined the transcription start site and nucleotide sequence of the 5' flanking region. Transfection of PC12 cells with a fragment from the 5' flanking region linked to the chloramphenicol acetyltransferase (CAT) gene revealed that it contains an element which imparts an NGF-inducible phenotype to the normally silent CAT gene. Several regions with homologies to recognizable sequence elements are present in this fragment, including a TATA box at nt -27, serum response elements at nt -84, -106, -370, and -408, a cAMP-responsive element at nt -140, and a transcription factor Sp1-binding site at nt -286. These results establish the genomic structure of this mammalian multifinger protein and demonstrate that an NGF-responsive element lies upstream of the NGFI-A gene.
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PMID:Structure of the NGFI-A gene and detection of upstream sequences responsible for its transcriptional induction by nerve growth factor. 249 4

The present work has examined the effects of okadaic acid, an inhibitor of serine/threonine protein phosphatase, PP-1 and PP-2A, on the regulation of EGR-1 gene expression in normal peripheral blood T- and Jurkat cells. The results demonstrate that okadaic acid treatment is associated with a transient induction of EGR-1 gene expression which was detectable by 30 min to 1 h and peaked at 3-6 h. EGR-1 mRNA was superinduced in cells treated with both okadaic acid and the protein synthesis inhibitor cycloheximide. The half-life of EGR-1 mRNA was similar in both control and okadaic acid-treated cells. In contrast, treatment with both okadaic acid and cycloheximide prolonged the half-life of EGR-1 transcripts. Nuclear run-on assays demonstrated that induction of EGR-1 gene expression by okadaic acid is controlled at least in part by a transcriptional mechanism. Transient expression assays with EGR-1 promotor fragments linked to the chloramphenicol acetyltransferase gene demonstrate that okadaic acid-induced EGR-1 transcription is conferred by the 5' most distal CArG box, CC (AT)6GG, in the EGR-1 promoter. Moreover, chloramphenicol acetyltransferase activity was induced by okadaic acid when the 5' most distal CArG element was linked to the heterologous herpes simplex virus thymidine kinase promoter, and not induced with a similar heterologous construct containing a mutated CArG sequence. These studies demonstrate that okadaic acid regulates EGR-1 gene expression at the transcriptional level via the CArG element and suggest that PP-1 and PP-2A play a role in T-cell activation.
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PMID:Involvement of serum response element in okadaic acid-induced EGR-1 transcription in human T-cells. 817 32

The expression of NGFIA (also known as egr1, zif268, TIS8, krox24, and d2) is rapidly and transiently increased by nerve growth factor (NGF) in PC12 cells. The 5'-region of this gene includes four serum response elements (SREs), a cAMP-like response element, an AP1-like response element, and an SP1-binding site. From deletion analysis of chloramphenicol acetyltransferase reporter constructs, we have established that the first 106 basepairs 5' of the transcriptional start site are sufficient for induction of NGFIA by NGF in PC12 cells; deletion beyond this point results in dramatically reduced induction of the gene. Using defined mutations in the NGFIA promoter and NGFIA-thymidine kinase hybrid promoters, we have defined three elements (SRE1, SRE2, and AP1-like) in the first 106 basepairs of upstream DNA, each of which contributes to induction of NGFIA by NGF. Cooperation by two of these elements (i.e. the two SREs or one SRE and the AP1-like element) is sufficient to confer transcriptional induction by NGF, but the combination of all three elements increased induction by NGF more effectively than a pair of elements. This suggests that the response of NGFIA to NGF is mediated by a cis-acting sequence that is composed of at least three distinct elements. An oligonucleotide composed of SRE1 and SRE2 that can confer the ability for NGF induction to heterologous promoter constructs complexes with proteins in PC12 cell nuclear extracts, but the protein-DNA complexes do not appear to be altered by NGF treatment, as measured by DNA mobility shift assays. We have also established that the regulatory region of NGFIA that mediates NGF induction also mediates the induction by serum and phorbol 12-myristate 13-acetate, suggesting that multiple signal transduction pathways must converge on these sequences to regulate the expression of this gene.
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PMID:Nerve growth factor induces transcription of NGFIA through complex regulatory elements that are also sensitive to serum and phorbol 12-myristate 13-acetate. 848 78

During herpes simplex virus (HSV) latency, in neurons of the nervous system, a single family of viral transcripts (the Latency-Associated Transcripts or LATs) are synthesized. Within the LAT promoter region, we have identified a consensus sequence for the EGR proteins in an unusual position immediately downstream of the TATA box. The early growth response (EGR) proteins are rapidly induced in cells by stimuli which also induce HSV to reactivate from latency. In order to determine if EGR proteins play any role in control of LAT transcription, we have analyzed the interactions between EGR proteins and the LAT promoter. Gel retardation and DNase I protection assays demonstrated that EGR1 zinc finger protein bound specifically to the LAT promoter region EGR consensus sequence. To determine if EGR proteins could modulate transcription through the LAT promoter, cotransfection assays were performed using chloramphenicol acetyltransferase (CAT) reporter constructs driven by either the wild-type LAT promoter or a LAT promoter with a mutated EGR binding site. Contransfection of the wild-type LAT promoter construct with EGR expression plasmids resulted in inhibition of the basal level of CAT activity with EGR-2 but not EGR-1 or 3. However, normal levels of CAT activity were observed in cotransfections using the mutant LAT promoter CAT construct suggesting that repression was mediated by the binding of EGR-2 proteins to the LAT promoter. Furthermore, data from combination binding assays using EGR1 and TATA binding protein (TBP) in vitro support the hypothesis that binding of EGR proteins to the LAT promoter prevents binding of TBP and thus suppresses transcription. These results may provide a link between stress responses in neurons of the CNS which activate the EGR family of proteins and HSV reactivation from latency due to the same stress response.
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PMID:Repression of the HSV-1 latency-associated transcript (LAT) promoter by the early growth response (EGR) proteins: involvement of a binding site immediately downstream of the TATA box. 920 69

ChAT (choline acetyltransferase) is the enzyme responsible for acetylcholine synthesis and is specifically expressed in cholinergic neurons. To further characterize the transcriptional regulation of the hCHAT (human ChAT) gene by NGF, we examined the effects upon ChAT promoter activity of a family of transcription factors which are activated by NGF and several extracellular stimuli and encoded by immediate-early genes. These include NGFI-A (Egr1, zif268), NGFI-C (Egr2), Krox-20 and NGFI-B (Nurr77). Two fragments of the hChAT gene were used for functional analysis carrying 944 bp (P1) and 4000 bp (P1 + P2) of the 5' flanking region in front of the chloramphenicol acetyltransferase (CAT) reporter gene. They were transiently co-transfected with NGFI-A, NGFI-C, Krox-20 and NGFI-B expression vectors in NG108-15, SN6 and COS-1 cells. CAT activity after transfection of the p4000 ChAT-CAT reporter into both neuronal cell lines (NG108-15 and SN6 cells) was increased up to 5-fold in the presence of co-transfected NGFI-A and up to 5- and 12-fold after co-transfection of NGFI-C expression vector in NG108-15 and SN6 cells, respectively. In NG108-15 cells, dbcAMP excerted a strong enhancing activity on the transactivation properties of NGFI-C while this was not observed when cells were transfected with NGFI-A. These trans-activation effects were specific for neuronal cells. When NG108-15 cells were treated with dbcAMP in the presence of H89, a specific PKA inhibitor, the increase of transcriptional activity of NGFI-C was abolished, indicating that a signalling transduction mechanism through PKA plays a role in NGFI-C-induced trans-activation. Electrophoretic mobility-shift assays showed that the sequence GCCCGGGGAG (NGFRE) located 1205 bp upstream of the first coding ATG (E1) can bind NGFI-A but not NGFI-C. Several possibilities explaining the observed results are discussed. Finally, transfections of ChAT-CAT reporters including the P1 + P2 region or a minimal ChAT enhancer present in the P2 region in front of a heterologous promoter indicated the presence of a regulatory element which conferred AP2-dependent trans-activation with homologous as well as with heterologous promoter constructs.
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PMID:Transcriptional activation of human choline acetyltransferase by AP2- and NGF-induced factors. 938 76