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)

Retinoic acid (RA) is known to influence the proliferation and differentiation of a wide variety of transformed and developing cells. We found that RA and the specific RA receptor (RAR) ligand Ch55 inhibited the phorbol ester and calcium ionophore-induced expression of the T-cell growth factor interleukin-2 (IL-2) gene. Expression of transiently transfected chloramphenicol acetyltransferase vectors containing the 5'-flanking region of the IL-2 gene was also inhibited by RA. RA-induced down-regulation of the IL-2 enhancer is mediated by RAR, since overexpression of transfected RARs increased RA sensitivity of the IL-2 promoter. Functional analysis of chloramphenicol acetyltransferase vectors containing either internal deletion mutants of the region from -317 to +47 bp of the IL-2 enhancer or multimerized cis-regulatory elements showed that the RA-responsive element in the IL-2 promoter mapped to sequences containing an octamer motif. RAR also inhibited the transcriptional activity of the octamer motif of the immunoglobulin heavy chain enhancer. In spite of the transcriptional inhibition of the IL-2 octamer motif, RA did not decrease the in vitro DNA-binding capability of octamer-1 protein. These results identify a regulatory pathway within the IL-2 promoter which involves the octamer motif and RAR.
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PMID:Retinoic acid-induced down-regulation of the interleukin-2 promoter via cis-regulatory sequences containing an octamer motif. 165 63

The chicken ovalbumin gene is regulated at the level of transcription by four classes of steroid hormones. A steroid-dependent regulatory element (SDRE) found from -900 to -732 is required for this steroid-mediated induction. To define more precisely sequences of the SDRE required for steroidal induction, a series of exonuclease III deletions were made in the 3' end of the SDRE. Fusion genes containing the mutant ovalbumin 5'-flanking sequences linked to the chloramphenicol acetyltransferase structural gene (CAT) were transfected into steroid-responsive primary oviduct cells. These functional studies defined a region of the SDRE from -793 to -759 that is essential for induction by steroids. Analysis of protein interactions in this 34-base pair region by copper-phenanthroline footprinting and methylation interference assays defined nucleotides required for protein binding. Footprinting showed protection of residues extending from -784 to -765, an area that included nucleotides that, when methylated, interfered with protein binding. In addition, this footprinted region contained 10 nucleotides that were identical to sequences contained in the beta-interferon gene regulatory element. An oligomer synthesized to this region of homology produced two DNA-protein complexes with oviduct nuclear proteins. Although this region of the interferon gene regulatory element binds the transcription factor NF-kappa B, an oligomer from the immunoglobulin kappa light chain gene known to bind NF-kappa B did not compete with the SDRE oligomer for binding to oviduct nuclear proteins. Surprisingly, this same NF-kappa B oligomer was able to restore steroid responsiveness to an SDRE mutant, while an oligomer from the immunoglobulin heavy chain gene inserted in the same position did not affect induction by steroids. These data suggest that a protein binding to sequences in the SDRE that are similar to an NF-kappa B-binding site participates in the steroid-mediated increase in transcription of the chicken ovalbumin gene.
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PMID:A protein with a binding specificity similar to NF-kappa B binds to a steroid-dependent regulatory element in the ovalbumin gene. 203 95

The organization of the cis-acting regulatory elements of a chick myosin heavy chain gene has been investigated. The data show that a gene which is transcribed in vivo in the fast white embryonic musculature is also the major transcript expressed during myotube differentiation of primary myoblasts derived from 12-day embryonic chick leg muscles. The upstream region of this gene consists of 7500 base pairs, and we have tested the ability of these sequences to drive expression of the chloramphenicol acetyltransferase gene in developing primary muscle cultures. Deletion analyses of the upstream region show that negative regulatory elements are present within 2000 base pairs of the basal promoter elements, the CCAAT and TAATA boxes. Removal of these elements reveals the presence of a strong positive element located near the start site of transcription. Sequence analysis showed that the region also contains a sequence characteristic of an enhancer found in the immunoglobulin heavy chain gene, ATGCAAAT, the "octa" element. Gel band-shift assays show that this octa sequence binds a transacting factor present in muscle nuclear extracts, although footprint analysis indicates a limited interaction. Transient assays carried out with a fragment in which the octa sequence has been mutated, with the subsequent abolition of protein binding, shows that the particular interaction probably plays a role in negatively modulating the action of the strong positive promoter element.
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PMID:Analysis of the upstream regulatory region of a chicken skeletal myosin heavy chain gene. 211 12