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)

RNA tools, namely, antisense RNA, double-stranded RNA (dsRNA), and delta ribozyme, were comparatively analyzed for the development of effective RNA-based gene modulators. The gene encoding uracil phosphoribosyltransferase (UPRT) of Toxoplasma gondii was used as a target and a negative selectable marker. Using plasmid transformation and drug selection assays, we obtained T. gondii transformants resistant to 5-fluoro-2'-deoxyuridine (FDUR), the cytotoxic prodrug and substrate of UPRT, when the plasmids expressing dsRNA and active delta ribozyme were used. No resistant transformants were detected when the plasmids carrying the antisense RNA, the inactive delta ribozyme, or the chloramphenicol acetyltransferase (CAT) genes were used. Parasites generated using the plasmids expressing dsRNA and the delta ribozyme become resistant to FDUR with an LD50 of 50 +/- 5 microM and 25 +/- 8 microM, respectively. These values are approximately 25-fold and 12-fold higher than that of the RH parental parasite strain, indicating that UPRT activity of the transformed parasites was drastically inhibited. Using Northern and Southern blot analysis, we demonstrated that dsRNA and the delta ribozyme interrupt the expression of UPRT. These two RNA tools should, thus, be very useful for the study of gene expression.
 ...
PMID:Comparative analysis of antisense RNA, double-stranded RNA, and delta ribozyme-mediated gene regulation in Toxoplasma gondii. 1223 16

We have developed a rapid, straightforward, one plasmid dual positive/negative selection system for the evolution of aminoacyl-tRNA synthetases with altered specificities in Escherichia coli. This system utilizes an amber stop codon containing chloramphenicol acetyltransferase/uracil phosphoribosyltransferase fusion gene. We demonstrate the utility of the system by identifying a variant of the Methanococcus jannaschii tyrosyl synthetase from a library of 10(9) variants that selectively incorporates para-iodophenylalanine in response to an amber stop codon.
 ...
PMID:One plasmid selection system for the rapid evolution of aminoacyl-tRNA synthetases. 1939 1