Transcription ribozymes

Reverse transcriptase (Section 28 13) Enzyme that catalyzes the transcription of RNA to DNA Ribozyme (Section 28 11) A polynucleotide that has catalytic activity... 

Cagnon, L., and Rossi, J. J. (2000). Down regulation of the CCRS beta-chemokine receptor and inhibition of HIV-1 infection by stable VAl-ribozyme chimeric transcripts. Antisen. Nuc. A. Drug Dev. 10 251—261. 

Some RNA molecules have intrinsic catalytic activity. The activity of these ribozymes often involves the cleavage of a nucleic acid. An example is the role of RNA in catalyzing the processing of the primary transcript of a gene into mature messenger RNA. 

Trans, commercial defoamer, 5 24 It Trans-cleaving ribozymes, 17 627 Transcription, 12 449 Transdermal drug delivery, 9 46-48 efficacy, 9 47 systems, 15 711... 

The hepatitis delta virus (HDV) ribozyme is part of the circular single stranded RNA genome of the hepatitis delta virus which consists of a total of 1700 nucleotides. The HDV ribozyme is required for the processing of multimers of the genomic linear RNA transcripts to unit length by catalyzing a transesterification reaction that results in self cleavage [23]. 

A ribozyme activity that led to RNA-modifications that are analogous to the 5 -5 pyrophosphate caps of eukaryotic RNA transcripts was selected by Huang and Yarns [84]. Actually the author s intention was to isolate ribozymes which catalyze the formation of a mixed anhydride between an amino acid carboxylate and a 5 -terminal phosphate of an RNA, an activity that is chemically analogous to the activation of amino acids by ATP catalyzed by aminoacyl tRNA synthetases. However, while the selected ribozymes did... 

Figure 4.4 Nucleolar localized anti-HIV-1 ribozyme. The anti-HIV-1 ribozyme was inserted within the apical loop of the small nucleolar RNA U16. The chimeric U16-ribozyme was placed behind the Pol III U6 snRNA promoter. Transcripts of the chimeric RNA localize to the nucleolus, as shown by the in situ hybridization and co-localization with the small nucleolar RNA U3. The in situ hybrids were performed in transfected 293 cells. The ribozyme probe was fluorescein labeled (green), whereas the U3 probe was labeled with Cy3 (red). Reproduced with permission from Michienzi et al. (2000). (see Color Plate 3)...

Stable intracellular expression of transcriptionally active ribozymes can be achieved by viral vector-mediated delivery. Currently, retroviral vectors are the most commonly used in cell culture, primary cells... 

Watanabe, T. and Sullenger, B.A. (2000) Induction of wild-type p53 activity in human cancer cells by ribozymes that repair mutant p53 transcripts. I roc. Natl. Acad. Sci. USA, 97, 8490-8494. 

It is important that Tris-containing buffers not be used in these reactions, particularly reaction 2. The reason is that Tris will induce slow selfcleavage of the glmS ribozyme (Batey and Kieft, 2007 McCarthy et al., 2005 Roth et al., 2006). Small amounts of Tris introduced into the transcription reaction from the PCR reaction should be avoided and can be alleviated by using HEPES-based buffers. Note that most commercial PCR buffers contain Tris. 

Fechter, P., Rudinger, J., Giege, R., and Theobald-Dietrich, A. (1998). Ribozyme processed tRNA transcripts with unfriendly internal promoter for T7 RNA polymerase Production and activity. FEBS Lett. 436, 99—103. 

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