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)

We have isolated a genomic clone containing the mouse neu gene. The 5' end of the mouse neu gene was localized by Southern analysis, subcloned and characterized. DNA sequence analysis revealed that the promoter region is 67% G+C-rich and lacks a TATA box, although a CAAT box is present. By sequence comparison, we identified several consensus recognition sequences for general transcription factors such as Sp1, E4TF1, AP2, OTF-1 and GCF, as well as recognition sequences for RVF, E1A and GTG, which have recently been identified in the rat neu promoter. Functional promoter activity was demonstrated by the ability of the promoter to drive transcription of the bacterial chloramphenicol acetyltransferase gene. Using a series of 5'-end deletion mutants, we have identified multiple positive and negative cis-acting elements that regulate mouse neu gene transcription.
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PMID:Cloning and characterization of the mouse neu promoter. 134 55

We used chloramphenicol acetyltransferase (CAT) assays to identify and characterize cis-acting elements responsible for rat neu promoter function. Deletion of a region of the neu promoter (-504 to -312) resulted in a marked decrease in CAT activity, indicating that this promoter region corresponds to a positive cis-acting element. Using band shift assays and methylation interference analyses, we further identified a specific protein-binding sequence, AAGATAAAACC (-466 to -456), that binds a specific trans-acting factor termed RVF (for EcoRV factor on the neu promoter). The RVF-binding site is required for maximum transcriptional activity of the rat neu promoter. This same sequence is also found in the corresponding regions of both human and mouse neu promoters. Furthermore, this sequence can enhance the CAT activity driven by a minimum promoter of the thymidine kinase gene in an orientation-independent manner, and thus it behaves as an enhancer. Our results demonstrate that RVF is the major DNA-binding protein contributing to enhancer activity. In addition, Southwestern (DNA-protein) blot analysis using the RVF-binding site as a probe points to a 60-kDa polypeptide as a potential candidate for RVF.
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PMID:Identification and characterization of a novel enhancer for the rat neu promoter. 167 39

The rat neu oncogene encodes a growth factor receptor-like glycoprotein, termed p185, that shares structural similarity with epidermal growth factor receptor (EGFR), particularly in the tyrosine-kinase domain. The Swiss Webster 3T3 murine embryo fibroblast (SW3T3) variant NR-6, in contrast to the parental cell line, does not express EGFR mRNA. After transfection of an activated rat neu cosmid clone, we demonstrated in this report that whereas SW3T3 cells readily expressed the exogenous rat p185 protein, NR-6 cells did not express detectable levels of this protein product. By transfection of plasmids containing the chloramphenicol acetyltransferase (CAT) gene driven by the neu promoter and subsequent CAT assays, we also showed that neu gene promoter activity was significantly less in NR-6 cells than in SW3T3 cells and that the neu promoter sequence responsible for this decreased transcription was a previously identified RVF enhancer element (Yan D-H, Hung M-C, Mol Cell Biol 11:1875-1882, 1991). That is to say, the RVF enhancer element of the neu promoter did not function as an enhancer in NR-6 cells. To investigate the mechanism responsible for the inactivation of RVF in NR-6 cells, we used southwestern blot analyses and demonstrated that the 60-kDa RVF polypeptide was present in both NR-6 and SW3T3 cell nuclear extracts. This result indicates that the DNA-binding activity of RVF was similar in these two cell lines; therefore, loss of RVF enhancer activity in NR-6 cells is probably due to inactivation of the trans-activating function and not DNA binding activity of RVF.
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PMID:Differential activity of the RVF enhancer element in the decreased expression of the neu oncogene in NR-6 cells versus parental Swiss Webster 3T3 cells. 809 19