Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BeWo cells, a human choriocarcinoma cell line, have a high-affinity system for transporting copper ions into the cell (Km = 0.21 microM) but are sluggish in releasing copper back into the medium from preloaded cells. The slow efflux rate has recently been shown to correlate with a failure of BeWo cells to express the Menkes transcript [Y. Qian, E. Tiffany-Castiglioni, and E. D. Harris. Am. J. Physiol. 271 (Cell Physiol. 40). In press]. We have now determined that only when BeWo cells were grown on plastic surfaces such as petri dishes or flasks did they display negligible release and enhanced retention of 67Cu. Reverse transcriptase-polymerase chain reaction with the use of primers selective for the Menkes gene failed to show any evidence of a Menkes transcript in cells cultured on plastic surfaces. In contrast, cells grown on porous filters previously shown to allow apical and basolateral surfaces to develop did display the transcript and showed significant copper release with normal retention. Release of copper from filter-grown cells was blocked with p-chloromercuribenzoate, thus confirming sulfhydryl group involvement. Absorption of the 67Cu, either as a free ion or bound to ceruloplasmin, was unaffected by the different culture conditions. The data link the Menkes gene product with the ability of cells to release copper ions. They also suggest that the expression of the Menkes gene may be regulated by the development of polarized cell membranes.
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PMID:Coincident expression of Menkes gene with copper efflux in human placental cells. 876 73

Saxitoxin is a potent neurotoxin produced by several species of dinoflagellates and cyanobacteria. The molecular target of saxitoxin in higher eukaryotes is the voltage-gated sodium channel; however, its target in lower eukaryotic organisms remains unknown. The goal of this study was to obtain the transcriptional fingerprint of the model lower eukaryote Saccharomyces cerevisiae upon exposure to saxitoxin to identify potential genes suitable for biomarker development. Microarray analyses identified multiple genes associated with copper and iron homeostasis and sulfur metabolism as significantly differentially expressed upon exposure to saxitoxin; these results were verified with quantitative reverse-transcriptase PCR (qRT-PCR). Additionally, the qRT-PCR assays were used to generate expression profiles in a subset of the differentially regulated genes across multiple exposure times and concentrations, the results of which demonstrated that overall, genes tended to respond in a consistent manner to the toxin. In general, the genes encoding the metallothioneins CUP1 and CRS5 were induced following exposure to saxitoxin, while those encoding the ferric/ cupric reductase FRE1 and the copper uptake transporter CTR1 were repressed. The gene encoding the multicopper ferroxidase FET3, part of the high-affinity iron uptake system, was also induced in all treatments, along with the STR3 gene, which codes for the cystathionine beta-lyase found in the methionine biosynthetic pathway.
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PMID:Transcriptional profiling of Saccharomyces cerevisiae upon exposure to saxitoxin. 1973 15