Transcription of nucleic acid

The human immunodeficiency virus replicates by converting its single-standed RNA into double-stranded DNA which is incorporated into host DNA this crucial conversion, the reverse of the normal cellular transcription of nucleic acids, is accomplished by the enzyme reverse transcriptase. Zidovudine, as the triphosphate, was the first anti-HIV drug to be introduced and has a high affinity for reverse transcriptase. It is integrated by it into the viral DNA chain, causing premature chain termination. The drug must be present continuously to prevent viral alteration of the host DNA, which is permanent once it occurs. 

Block the biosynthesis or transcription of nucleic acids to check cell-division through direct interference with mitotic spindles,... 

If an antibody to the protein of interest is available, it is sometimes possible to use vector sequences, eg, the beta-galactosidase promoter sequence, to direct the transcription of the passenger DNA into messenger RNA and the translation of that mRNA into protein which can be recognized by the antibody. Although this method is somewhat less reHable than the use of nucleic acid probes, specialized vectors are available for this purpose. 

Transcription Template DNA-directed synthesis of nucleic acids typically DNA-directed synthesis of RNA. 

Several of the enzymes involved in the processes of repheating, transcription and reverse transcription are available commercially and are used by molecular biologists in the manipulation of nucleic acids. One of the most important of these is Taq polymerase (Taq), which is a thermostable DNA polymerase named after the thermophihe bacterium Thermus aquaticus from which it was originally isolated. This enzyme is especially important, as it is central to the technique known as PCR, which allows sophisticated, targeted in vitro amplification and manipulation of sections of DNA or RNA. DNA... 

Decoville, M., Giraud-Panis, M.J., Mosrin-Huaman, C., Leng, M., and Locker, D. (2000) HMG boxes of DSPl protein interact with the rel homology domain of transcription factors. Nucleic Acids Res. 28, 454-462. 

Like chloroquine, quinine binds with plasmodium DNA, thus interfering in the synthesis of nucleic acids and preventing its replication and transcription. Quinine also suppresses a large portion of the enzymatic system and therefore it is characterized as a general protoplasmid toxin. This fact agrees well with the action of quinine on membranes, its local anesthetizing and its cardiodepressive effects. 

Lukens, A., King, D. and Marmorstein, R. (2000). Structure of HAP1-PC7 bound to DNA impUcations for DNA recognition and allosteric effects of DNA-binding on transcriptional activation. Nucleic Acids Res. 28, 3853-3863. 

Figure 7.5 Intercalation of carcinogens into the stacked bases of nucleic acids. Both carcinogens and certain anti-neoplastic agents share a common mechanism of action. They have the capacity to insert themselves into the nucleic acid structure, causing geometrical distortions that preclnde the ability of the nucleic acid to complete its function in the processes of transcription and translation. Flat aromatic molecules have the ability to intercalate between the stacked bases.

The intercalating drugs and nucleic acid synthesis inhibitors discussed in the preceding sections interfere indirectly with every phase of nucleic acid action because the DNA is rendered nonfunctional. Other drugs, discussed below, affect the regulation of protein synthesis even when the genome, the DNA structure, is intact. Such activity can be the result of interference either with transcription of messenger RNA or with translation of the mRNA to protein. 

These enzymes catalyze the replication and transcription of DNA, and have a specific requirement for Mg2+ or Mn2+." Both enzymes have been thought to require Zn2+ in addition,334,335 in accord with the well-known effect of zinc deficiency on Euglena gracilis, which results in defects in synthesis of nucleic acids and proteins, and in cell division. However, it appears now that the DNA polymerase is not a zinc enzyme.336... 

Cagnon, L. and Rossi, J.J. (2000) Downregulation of the CCR5 beta-chemokine receptor and inhibition of HIV-1 infection by stable VAl-ribozyme chimeric transcripts. Antisense Nucleic Acid Drug Dev., 10, 251-261. 

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