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:2.3.1.28 (chloramphenicol acetyltransferase)
5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of prostate-specific antigen (PA) mRNA was tested at various time periods after incubation of the human prostate tumor cell line LNCaP with the synthetic androgen R1881. Androgen-stimulated expression was observed within 6 h after addition of R1881 to the cells. Run-on experiments with nuclei isolated from LNCaP cells showed that expression of the PA gene could be regulated by R1881 on the level of transcription. DNase I footprints of the promoter region of the PA gene (-320 to +12) with nuclear protein extracts from LNCaP cells showed at least four protected regions. The protected areas include the TATA-box, a GC-box sequence, and a sequence AGAACAgcaAGTGCT at position -170 to -156, which closely resembles the reverse complement of the consensus sequence GGTACAnnnTGTTCT for binding of the glucocorticoid receptor and the progesterone receptor. Fragments of the PA promoter region were cloned in front of the chloramphenicol acetyltransferase (CAT) reporter gene and cotransfected with an androgen receptor expression plasmid into COS cells in a transient expression assay. CAT activity of COS cells grown in the presence of 1 nM R1881 was compared to untreated controls. A 110-fold induction of CAT activity was found if a -1600 to +12 PA promoter fragment was used in the construct. By further deletion mapping of the PA promoter a minimal region (-320 to -155) was identified as being essential for androgen-regulated gene expression. Mutation of the sequence AGAACAgcaAGTGCT (at -170 to -156) to AAAAAAgcaAGTGCT almost completely abolished androgen inducibility of the reporter gene constructs. One or more copies of the sequence AGAACAgcaAGTGCT cloned in front of a thymidine kinase promoter-CAT reporter gene confers androgen regulation to the reporter gene. These findings provide strong evidence for transcription regulation of the PA gene by androgens via the sequence AGAACAgcaAGTGCT. Interestingly, in addition to the AGAACAgcaAGTGCT element, an upstream region (-539 to -320) is needed for optimal androgen inducibility of the PA promoter.
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PMID:The promoter of the prostate-specific antigen gene contains a functional androgen responsive element. 172 87

The ets oncogene superfamily consists of a family of sequence-specific DNA-binding proteins that activate transcription. We have previously identified two new members of the ets oncogene superfamily, namely elk-1 and elk-2. In this report we show that the recombinant elk-1 protein expressed in bacteria, like the c-ets-1 proto-oncogene, binds in a sequence-specific manner to Moloney murine sarcoma virus long terminal repeat, E74 target sequences and the PEA3 motif (polyoma enhancer), but does not bind to PU box sequences. Thus analysis of the DNA-binding specificity of ets-related proteins supports the view that different members show similar DNA-binding specificity, which is a general feature of the homeobox proteins. Our data using the chloramphenicol acetyltransferase gene linked to a thymidine kinase promoter containing multimers of the elk-1 target sequence indicates that elk-1 functions as a transcriptional activator. Interestingly, although elk-1 is the most divergent of all the members of the ets gene family, it shows very close similarities with c-ets-1 in some of its sequence-specific DNA-binding specificities. Here, we propose a new function for the elk-1 gene to act as a transcriptional activator of retroviruses and DNA tumor viruses.
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PMID:A divergent ets-related protein, elk-1, recognizes similar c-ets-1 proto-oncogene target sequences and acts as a transcriptional activator. 174 Nov 66

This is a retrospective study of 37 patients with endometrial carcinoma and presence of tumor on endocervical curettage (clinical Stage II). We intended to correlate the presence or absence of endocervical stromal invasion with the clinical behavior and other prognostic factors. Based on the endocervical curettage, three categories (CAT) were defined: CAT I: tumor fragments only (seven cases); CAT II: endocervical tissue and free-floating tumor fragments (13 cases); and CAT III: endocervical tissue and tumor with evidence of stromal invasion (17 cases). Five tumors were partly of clear cell and/or papillary serous types and three of them belonged to CAT I. Six of seven tumors with a nuclear Grade 3 were in CAT III (p less than 0.05). Nine patients had local recurrence, metastases, or died of their disease (median follow-up: 56 mo) and seven of them were in the CAT III (p less than 0.05). We conclude that despite the presence of tumor on the endocervical curettage, the lack of endocervical tissue invasion is associated with a lower nuclear grade and a less aggressive behavior. These tumors should be regarded and treated as Stage I disease. Special attention must be paid to staging of clear cell and papillary serous adenocarcinomas because of the tendency for these tumors to contaminate the endocervical curettage.
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PMID:Endocervical involvement by endometrial carcinoma on fractional curettage: a clinicopathological study of 37 cases. 175 76

TR3 receptor is a human homolog of mouse Nurr77 and N10 protein and the rat NGFI-B protein. A cDNA encoding a chimeric nuclear receptor composed of the N-terminal domain and C-terminal putative ligand-binding domain of the orphan receptor TR3 receptor and the DNA-binding domain of the androgen receptor was constructed. The chimeric receptor, called TR3/AR/TR3 receptor, when expressed in COS-1 monkey kidney cells or PC-3 human prostate tumor cells, cotransfected with an ARE-containing mouse mammary tumor virus long terminal repeat-linked reporter gene encoding chloramphenicol acetyltransferase (CAT), activated CAT expression in the absence of any added factor. The activation was dependent on the amount of expression vector transfected and appeared to be independent of the concentration of serum supplement. Intact TR3 receptor was not active in this system. A TR3/AR/TR3 receptor protein truncated in the putative ligand-binding domain also induced CAT activity. TR3 receptor appears to be a transcriptional factor that activates transcription independently of ligand or binds an endogenous ligand present constitutively in cultured cells.
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PMID:Transcriptional activation by TR3 receptor, a member of the steroid receptor superfamily. 184 11

The mechanism of regulatory expression of human cytochrome P-450scc gene by cAMP was investigated in a transient expression system using Y-1 cells (mouse adrenal tumor cell line) and a chimeric DNA composed of the structural gene for bacterial chloramphenicol acetyltransferase and the 5' flanking upstream sequence of the cytochrome P-450scc (cholesterol desmolase) gene which was revealed to contain a DNA element(s) responsive to cAMP [Inoue, H. et al. (1988) Eur. J. Biochem. 171, 435-440]. Introduction of deletions and point mutations in the upstream regulatory sequence demonstrated that three regions were mainly required for response to cAMP. These regions contained a short similar sequence. All of them have a 5-bp motif GTCAT (or ATGAC) in common, and have at least two motifs which conserve four out of five base pairs of the consensus sequence of the cAMP-responsive element (CRE), CGTCA (or TGACG). They are all apparently necessary for regulation by cAMP. Gel mobility shift assays suggested that a binding factor(s) to these regions was present in the nuclear extracts of Y-1 cells and adrenal cortex tissues and appeared to be different from the somatostatin CRE-binding protein. Deletion analysis also suggested that the region around -44 was essential to the basal transcriptional activity. This region shows some similarity to the CTF NF-1 binding site [Johnson and McKnight (1989) Annu. Rev. Biochem. 58, 799-839].
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PMID:Structures of regulatory regions in the human cytochrome P-450scc (desmolase) gene. 184 89

The platelet-derived growth factor (PDGF) A- and B-chain genes are widely expressed in mammalian tissues and their homodimeric gene products appear to regulate the autocrine growth of both normal and transformed cells. In this study, we analyzed the 5' flanking sequences of the human PDGF A-chain gene to seek elements important to regulating its transcription. The promoter region was exceptionally G + C-rich and contained a "TATA box" but no "CAAT box." The transcription start site was identified 845 base pairs 5' to the translation initiation site by S1 nuclease mapping and by primer extension. Both in vitro transcription and transient expression of the chloramphenicol acetyltransferase gene linked to the PDGF A-chain 5' flanking sequences established that the putative promoter region was active, and RNase H mapping established that the three characteristic mRNAs (1.9, 2.3, and 2.8 kilobases) used the same transcription start site, which was used in normal endothelial cells and in two human tumor cell lines that express high levels of A-chain transcripts. The results established an exceptionally G + C-rich promoter region and a single transcription start site active for each of the three mRNAs of the PDGF A-chain gene. DNA sites of potential importance in mediating the activation of the PDGF A-chain gene in normal cells and in transformed cell lines expressing high levels of PDGF A chain were identified.
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PMID:Promoter region of the human platelet-derived growth factor A-chain gene. 184 7

A deletion in an Alu repetitive sequence in the fifth intron of the c-sis gene of meningioma patients was previously described (M. Smidt et al., J. Clin. Invest., 86:1151-1157, 1990). The authors analyzed the structure of this intron in DNA from peripheral blood leukocytes and tumor samples of 86 patients with sporadic meningiomas. After amplifying these DNA sequences by the polymerase chain amplification reaction, the authors failed to find any cases with deletions. They also analyzed the effects on the expression of c-sis of the fifth intron with or without the deletion. A c-sis expression clone with an SV40 promoter was modified by adding introns 4, 5, and 6, and the resulting clones were used to examine the expression of c-sis mRNA in A172, NIH3T3, and Cos-7 cells. Northern blots showed that the quantity of message was not changed when the introns were present and that the size of the message was not changed by the deletion in the fifth intron. The effect of the fifth intron Alu sequence on the c-sis promoter was also tested using clones with chloramphenicol acetyltransferase as a reporter gene in A172 and Cos-7 cells. The c-sis promoter was not affected by the fifth intron Alu sequence with or without the deletion and in either orientation. There were also no effects when cells were stimulated by phorbol 12-myristate 13-acetate or the regulatory gene Tax from human T-lymphotropic virus type 1. These data do not support a role for deletions in the fifth c-sis intron in the development of most sporadic meningiomas.
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PMID:Structure and expression of the c-sis gene and its relationship to sporadic meningiomas. 186 50

The t(9;22) Philadelphia chromosome translocation fuses 5' regulatory and coding sequences of the BCR gene to the c-ABL proto-oncogene. This results in the formation of hybrid BCR-ABL mRNAs and proteins. The shift in ABL transcriptional control to the BCR promoter may play a role in cellular transformation mediated by this rearrangement. We have functionally localized the BCR promoter to a region 1 kb 5' of BCR exon 1 coding sequences by using a chloramphenicol acetyltransferase reporter gene assay. Nucleotide sequence analysis of this region revealed many consensus binding sequences for transcription factor SP1 as well as two potential CCAAT box binding factor sites and one putative helix-loop-helix transcription factor binding site. No TATA-like or "initiator" element sequences were found. Because of low steady-state levels of BCR mRNA and the high GC content (78%) of the promoter region, definitive mapping of transcription start sites required artificial amplification of BCR promoter-directed transcripts. Overexpression from the BCR promoter in a COS cell system was effective in demonstrating multiple transcription initiation sites. In order to assess the effects of chromosomal translocation on the transcriptional control of the BCR gene, we determined S1 nuclease protection patterns of poly(A)+ RNA from tumor cell lines. No differences were observed in the locations and levels of BCR transcription initiation sites between those lines that harbored the t(9;22) translocation and those that did not. This demonstrates that BCR promoter function remains intact in spite of genomic rearrangement. The BCR promoter is structurally similar to the ABL promoters. Together, this suggests that the structural fusion of BCR-ABL and not its transcriptional deregulation is primarily responsible for the transforming effect of the t(9;22) translocation.
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PMID:Characterization of the BCR promoter in Philadelphia chromosome-positive and -negative cell lines. 190 Sep 18

Regulation of human thyrotropin beta subunit gene (TSHB) expression by thyrotropin-releasing hormone (TRH) was examined in a clonal rat pituitary-cell line (GH3). Transient expression studies were done with various 5'-flanking DNA sequences of TSHB coupled to reporter gene chloramphenicol acetyltransferase. Deletion analysis defined two discrete regions (-128 to -92 base pairs and -28 to +8 base pairs) that each mediated an approximately 2-fold TRH induction. The upstream site contains a DNA sequence with close homology to the DNA-binding site for a pituitary-specific transcriptional factor Pit-1/GHF-1. DNase I footprinting analysis of mouse thyrotropic tumor extract as well as DNA-transfection studies using an expression vector containing an N-terminal deletion of Pit-1/GHF-1 cDNA suggest that Pit-1/GHF-1 or a closely related protein in the thyrotroph mediates TRH responsiveness of this gene. In addition, the downstream site overlaps with the recently characterized thyroid hormone-inhibitory element of TSHB. In fact, deletion of DNA sequences important in thyroid hormone-receptor binding (c-erbAB/c-ERBA2) from +3 to +8 base pairs, significantly reduced (30%) TRH responsiveness. The location of a TRH-stimulatory element near a thyroid hormone-inhibitory element may allow for fine control of TSHB expression in vivo.
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PMID:Thyrotropin-releasing hormone regulation of human TSHB expression: role of a pituitary-specific transcription factor (Pit-1/GHF-1) and potential interaction with a thyroid hormone-inhibitory element. 190 56

A bovine genomic library was constructed using a cosmid vector, pHC79, and bovine DNA partially digested by EcoRI. Bovine P-450(11 beta) cDNA, pcP-450(11 beta)-2 [Morohashi et al. (1987) J. Biochem. 102,559-568], was used as a probe for screening the genomic library. Ten clones carrying P-450(11 beta) genomic DNA were isolated from 8 x 10(4) colonies and classified into five groups (CB11 beta-1, CB11 beta-3, CB11 beta-7, CB11 beta-20, and CB11 beta-21) according to differences in the restriction endonuclease sites. Nucleotide sequences of amino acid coding regions of the five clones were determined by the dideoxy sequencing method using synthetic nucleotides corresponding to various parts of the cDNA as primers. The nucleotide sequences revealed that three clones, CB11 beta-1, CB11 beta-3, and CB11 beta-21, were pseudogenes. Amino acid sequences coded by the other two clones, CB11 beta-7 and CB11 beta-20, were identical with that coded by a previously described cDNA, pcP-450(11 beta)-3 [Kirita et al. (1988) J. Biochem. 104, 683-686]. The promoter regions of the five clones were introduced in front of chloramphenicol acetyltransferase (CAT) gene of pSV00CAT and used to examine P-450(11 beta) gene regulation in cultured cells. The five recombinant plasmids showed cAMP-responsive CAT activities in Y-1 cells, a cell strain derived from adrenal tumor. The induction rates of the recombinant plasmids carrying the promoters of normal genes, CB11 beta-7 and -20, were larger than those of pseudogenes, CB11 beta-1, -3, and -21. CAT activities expressed by the promoter regions of the normal genes in the presence or absence of cAMP in Y-1 cells were almost equal to that by the promoter region of human P-450(SCC) gene. Though the promoter of the P-450(SCC) gene also showed cAMP-responsive CAT activity in I-10 cells, a cell strain derived from Leyding cell tumor, P-450(11 beta) gene promoter did not express the activity in I-10 cells.
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PMID:Structural analysis of multiple bovine P-450(11 beta) genes and their promoter activities. 196 87


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