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Target Concepts:
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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)
We found that the expression of human
platelet-activating factor receptor
(
PAFR
) gene is differentially regulated by estrogen and TGF-beta 1. Primer extension analysis revealed that the levels of the
PAFR
transcript 2 were increased by estrogen, but decreased by TGF-beta 1 in the human stomach cancer cell line (JR-St cells) which expressed both functional endogenous
PAFR
transcript 1 (leukocyte-type) and transcript 2 (tissue-type). Both ligands did not affect the expression of intrinsic
PAFR
transcript 1. Furthermore, the response elements to estrogen and TGF-beta 1 in the
PAFR
promoter 2 were delineated by a transient expression assay using the
chloramphenicol acetyltransferase
(
CAT
) gene as a reporter in this cell line. A negative response element for TGF-beta 1 was mapped on the sequence from -90 bp to -81 bp, which has consensus sequence for TIE (TGF-beta 1 inhibitory element). Although consensus estrogen response element (AGGTCAnnnTGACCT) is not present in this promoter, the entire sequence comprising two AGGTCA half motifs spaced by 153 bp (from -257 bp to -93 bp) conferred weak but significant estrogen responsiveness. Thus, through these elements in the
PAFR
promoter 2, estrogen and TGF-beta 1 may regulate the
PAFR
gene to achieve a tissue-specific expression.
...
PMID:Positive and negative regulations of human platelet-activating factor receptor transcript 2 (tissue-type) by estrogen and TGF-beta 1. 780 41
The human
platelet-activating factor receptor
(
PAFR
) gene is transcribed by two distinct promoters (promoter 1 and promoter 2) to generate two transcripts (designated as
PAFR
transcript 1 and
PAFR
transcript 2), though their open reading frames are identical. By primer extension analysis to discriminate two transcripts, we found that the levels of
PAFR
transcript 1 (leukocyte-type), but not
PAFR
transcript 2 (tissue-type), are upregulated by PAF as well as by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the human stomach cancer cell line (JR-St cells) which expresses both functional
PAFR
transcript 1 and
PAFR
transcript 2 endogenously. Functional analysis of the promoter 1 with a transient expression assay using
chloramphenicol acetyltransferase
(
CAT
) gene as a reporter showed that both PAF and TPA activated the promoter 1 but not the deleted promoter lacking the three consensus binding sites for NF-kappa B located from -571 bp to -459 bp. These findings suggest a molecular mechanism of positive regulation of
PAFR
gene expression by PAF through NF-kappa B, possibly by a phosphorylation reaction involving protein kinase C by PAF.
...
PMID:Platelet-activating factor (PAF) positively auto-regulates the expression of human PAF receptor transcript 1 (leukocyte-type) through NF-kappa B. 780 42
