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)

We have recently cloned a cDNA encoding a mutant form of PRL receptor (PRL-R) from Nb2 cells, a PRL-dependent T lymphocyte-derived cell line. This cDNA is identical to the long form of the rat PRL-R, except for a deletion of 594 base pairs in the cytoplasmic domain, resulting in a mature receptor protein of 393 amino acids. Although a segment containing three cytoplasmic regions of moderate to high amino acid sequence identity with members of the PRL/GH receptor family is missing in this receptor form, the region of highest (70%) identity is retained. In the following studies, a homologous functional assay was developed to test the activity of three forms of receptor with respect to their ability to transmit a lactogenic signal. In this system, CHO cells were transiently transfected with a construct containing 2300 base pairs of the 5'-flanking sequence of the rat beta-casein gene fused to the chloramphenicol acetyltransferase (CAT) gene and an expression vector containing the various forms of rat PRL-R cDNA. The transfected cells were grown in serum-free medium in the absence or presence of PRL. In cells transfected with the long form of the PRL-R and beta-casein/CAT construct, a 7.2- +/- 0.9-fold induction (n = 3) of CAT activity was seen when cells were cultured in the presence of 400 ng/ml PRL and 1 micrograms/ml hydrocortisone. This level of stimulation was similar to that observed for the ovine beta-lactoglobulin/CAT construct in which a 5.7- +/- 1.2-fold (n = 3) effect was found.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The Nb2 form of prolactin receptor is able to activate a milk protein gene promoter. 140 2

We demonstrate that a member of the fos family, the fosB gene, gives rise to two transcripts by alternative splicing of exon 4, generating two proteins, FosB of 338 amino acids and a short form, FosB/SF, which contains the DNA binding and dimerization domains but not the 101 amino acids of the C terminus. FosB/SF activates an AP-1-chloramphenicol acetyltransferase construct in NIH 3T3 cells, as determined by transient and stable transfections, although more weakly than does FosB. In contrast to FosB, FosB/SF has lost its ability to repress the dyad symmetry element of the c-fos gene. FosB/SF when expressed in excess to FosB can downmodulate the activity of FosB. Constitutive expression of high levels of FosB/SF in NIH 3T3 cells has no significant inhibitory effect in the induction of cell proliferation or cell cycle progression, indicating that FosB/SF is not a negative regulator of cell growth. This conclusion is further confirmed by the observation that the majority of the Jun molecules are complexed with FosB/SF in the FosB/SF-overexpressing cells.
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PMID:Both products of the fosB gene, FosB and its short form, FosB/SF, are transcriptional activators in fibroblasts. 192 60

The biological activities of long and short forms of the prolactin receptor have been compared. These two receptors expressed in mammalian cells were shown to bind prolactin with equal high affinity. The ability of these different forms to transduce the hormonal message was estimated by their capacity to stimulate transcription by using the promoter of a milk protein gene fused to the chloramphenicol acetyltransferase (CAT) coding sequence. Experiments were performed in serum-free conditions to avoid the effect of lactogenic factors present in serum. An approximately 17-fold induction of CAT activity was obtained in the presence of prolactin when the long form of the prolactin receptor was expressed, whereas no induction was observed when the short form was expressed. The present results clearly establish that only the long form of the prolactin receptor is involved in milk protein gene transcription.
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PMID:Comparison of long and short forms of the prolactin receptor on prolactin-induced milk protein gene transcription. 199 73