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)

Platelet-derived growth factors (PDGFs) are growth-regulatory molecules that stimulate chemotaxis, proliferation, and increased metabolism of primarily connective tissue cells. In a survey of normal tissues, we found specific immunostaining for PDGF B-chain in neurons, principal dendrites, some axons, and probable terminals throughout the brain, in the dorsal horn of the spinal cord, and in the posterior pituitary of a nonhuman primate (Macaca nemestrina). PDGF activity was extracted from brain cortex and posterior pituitary, and ubiquitous expression of transcripts for the two chains of PDGF and both PDGF receptors was detected throughout the brain and posterior pituitary. A transgenic model was also evaluated in which the chloramphenicol acetyltransferase gene was placed under transcriptional control of the PDGF B-chain promoter. The transgene was preferentially expressed within neural cell bodies in the cortex, hippocampus, and cerebellum. PDGF may act as a neuronal regulatory agent. Neuronal release of PDGF could contribute to nerve regeneration and to glial proliferation that leads to gliosis and scarring.
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PMID:PDGF B-chain in neurons of the central nervous system, posterior pituitary, and in a transgenic model. 198 68

By using chloramphenicol acetyltransferase (CAT) assays in neuron-derived cell lines, we show here that promoter activity associated with the herpes simplex virus type 1 latency-associated transcript (LAT) had neuronal specificity. Promoter activity in these transient CAT assays coincided with a DNA region containing excellent RNA polymerase II promoter consensus sequences. Primer extension analysis in a LAT promoter-CAT plasmid construct placed the start of transcription about 28 nucleotides from the first T in the consensus TATA box sequence. Neuronal specificity of this promoter was suggested by examining the effect of sequences upstream of the promoter on CAT activity in neuronal versus nonneuronal cells. In nonneuronal cells, promoter activity was decreased 3- to 12-fold with the addition of upstream sequences. In contrast, in neuron-derived cells, the addition of upstream sequences did not decrease promoter activity. The LAT promoter predicted by our transient CAT assays was located over 660 nucleotides upstream from the 5' end of the previously mapped 2-kilobase (kb) LAT. This unusual location was explained by in situ and Northern (RNA) blot hybridization analyses that suggested that LAT transcription began near the promoter detected in our CAT assays, rather than near the 5' end of the 2-kb LAT. In situ hybridization with neurons from latently infected rabbits detected small amounts of LAT RNA within 30 nucleotides of the consensus TATA box sequence. This suggested that LAT transcription began near this TATA box. Northern blot hybridization of RNA from ganglia of latently infected rabbits revealed a faint 8.3-kb band of the same sense as LAT. We conclude that (i) the LAT promoter has neuronal specificity, (ii) the LAT promoter is located over 660 nucleotides upstream of the 5' end of the previously characterized stable 2-kb LAT, (iii) LAT transcription begins about 28 nucleotides from the first T of the consensus TATA box sequence and extends to near the first available polyadenylation site approximately 8.3 kb away, and (iv) this 8.3-kb RNA may be an unstable precursor of the more stable 2- and 1.3-kb LATs.
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PMID:Activity of herpes simplex virus type 1 latency-associated transcript (LAT) promoter in neuron-derived cells: evidence for neuron specificity and for a large LAT transcript. 216 84

Neuronal migration in brain is followed by differentiation of committed neurons and simultaneous apoptosis of uncommitted preneuronal cells due to a limiting supply of trophic factors and nutrients. We have dissected differentiation and apoptosis by designing a simple in vitro model for this nutrient deprivation using engineered neuronal cell lines stably transfected with a promoterless segment (G-21) of the intronless human serotonin1A receptor (5-HT1A-R) gene. Despite the use of widely different heterologous promoters (cytomegalovirus and Rous sarcoma virus) for the stable expression of G-21, a dramatic increase in expression of the 5-HT(1A)-R (five- to 15-fold) and its mRNA was always observed during degeneration and apoptosis of nutrient-deprived neuronal cells. Involvement in this induction of a 170-bp 5'-end untranslated sequence (5'-UT) (tail end of the 500-bp natural promoter) of G-21 was confirmed by stable transfection of neuronal cells with an SV-40 promoter-driven construct harboring the 5'-UT and the reporter chloramphenicol acetyltransferase (CAT) cDNA. Presence of the 5'-UT resulted in a threefold increase in CAT expression during nutrient deprivation in randomly chosen clones. The induction was also observed in the endogenous 5-HT1A-R, expressed by embryonic day 16 mouse hippocampal neurons, subsequent to nutrient deprivation and onset of degeneration. A trophic role of the 5-HT1A-R has been suggested in earlier studies. Considering the example of protective heat shock proteins, which are induced during various types of stress, our results suggest that stressed neuronal cells undergoing degeneration and apoptosis synthesize increased levels of 5-HT1A-R as a final attempt to survive.
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PMID:Induction of the serotonin1A receptor in neuronal cells during prolonged stress and degeneration. 863 58