Inhibition of gene expression

Transcription factor DNA-binding motif Groove recognition Proposed mechanism of inhibition 

Ets-1 Winged helix-turn-helix Major Phosphate interference 

Dpi Basic helix-loop-helix Major Phosphate interference 

III in vitro and in cultured Xenopus kidney cells [60]. Further studies used polyamides in combination with recombinant derivatives of TFIIIA subunits to elucidate essential minor groove contacts for the binding of this TF (Tab. 3.1) [62]. 

This early biological result spurred a variety of biochemical studies of the interactions of various polyamides with the basal transcription machinery and TE-DNA complexes. Two studies have used promoter scanning to identify sites where polyamide binding inhibits transcription [64, 65]. The method uses a series of DNA constructs with designed polyamide binding sites at varying distances from 

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Antisense therapy means the selective, sequence-specific inhibition of gene expression by single-stranded DNA oligonucleotides. By hybridizing to the target mRNA, which results in a subsequent double-helix formation, gene expression is blocked. This process can occur at any point between the conclusion of transcription and initiation of translation or even possibly during translation. 

Good L., Nielsen P.E. Antisense inhibition of gene expression in bacteria by PNA targeted to mRNA. Nature Biotech-nol. 1998 16 355-358. 

Stock R. P., Olvera A., Sanchez R., Saralegui a., Scarei S., Sanchez-Lopez R., Ramos M.A., Boeea L.C., Benatti U., Alagon a. Inhibition of gene expression in Entamoeba histolytica with anti-sense peptide nucleic acid oligomers. Nature Biotechnol. 2001, 19 231-234. 

C. G., Janowski B.A., Corey D. R. Inhibition of gene expression inside cells by peptide nucleic acids effect of mRNA target sequence, mismatched bases, and PNA length. Biochemistry 2001 40 53-64. 

GCGCC-C —5 "discriminator" sequence inhibition of gene expression by ppGpp... 

Another group of researchers reported the first successful systemic selective inhibition of gene expression using antisense oligonucleotides. 

Figs. 12—16 to 12—22) and prevent the progressive course of Alzheimer s disease. Direct inhibition of gene expression for the biosynthesis of these proteins is not currently possible and is currently not a very feasible therapeutic possibility. Perhaps a more realistic therapeutic possibility would be to inhibit the synthesis of beta amyloid, in much the same way that lipid-lowering agents act to inhibit the biosynthesis of cholesterol in order to prevent atherosclerosis. This could be done by means of enzyme inhibitors, such as protease inhibitors, which are at least a theoretical possibility. 

This approach includes the production and purification of antisense transcripts in vitro and then the introduction of the antisense RNA into cells by microinjection. Compared to the antisense gene approach described above, a major advantage of this method is that a much larger amount of antisense RNA can be introduced into cells. Also, antisense RNA can be injected at a specific time and can therefore result in the transient inhibition of gene expression, which can be used in studies of gene expression at a specific time within a particular window of development. However, as RNAs are extremely sensitive to nuclease degradation, the potential pharmacological uses of antisense RNA are limited. 

Stein, C.A. and Cheng, Y.C. (1997) Antisense inhibition of gene expression. In V.T.De Vita, S.Hellman and S.A.Rosenberg (eds) Cancer Principles and Practice of Oncology, Lippincott-Raven, Philadelphia, pp. 3059-3074. 

Caplen NJ, Parrish S, Imani F, Fire A, Morgan RA (2001) Specific inhibition of gene expression by small double-stranded RNAs in invertebrate and vertebrate systems. Proc Natl Acad Sci USA 98 9742-9747... 

GoodchildJ. Inhibition of gene expression by oligonucleotides. In Cohen J, ed. Oligonucleotides Antisense Inhibitors of Gene Expression, London, UK MacMillan press, 1989 53-77. 

Fig. 5.2.1. Schematic representation of ribozyme based inhibition of gene expression.

The formation of cross-links on DNA has the potential to affect directly two essential cellular processes, replication and transcription. Early work demonstrated that cisplatin could inhibit replication under conditions that did not block transcription or translation [2], Adducts formed by trans-DDP can also inhibit DNA polymerases [4], however, and it has become evident that cisplatin lesions are not absolute blocks for replication (see the review by Villiani et al, this book). Furthermore, cisplatin commonly causes an arrest in the G2 phase of the cell cycle [149], suggesting that inhibition of gene expression, and not replication, determines whether the cell will live and divide, or undergo apoptosis. 

Hwang S, Tamilarasu N, Ryan K, Huq I, Richter S, Still W, Clark Rana TM, Inhibition of gene expression in human cells through small molecule-RNA interactions, Proc. Natl. Acad. Sci. USA, 96 12997-13002, 1999. 

Linear PEI None CMV-H1 Stereotaxic injection into lateral ventricles Normal brain Mice Brain TRal Inhibition of gene expression (55)... 

Chemical genomic profiling - using microarrays to determine the effects of highly specific drug-mediated kinase inhibition of gene expression. 

SPECIFIC INHIBITION OF GENE EXPRESSION Antisense nucleic acid drugs GENE THERAPY... 

Braasch DA, Liu Y, Corey DR. Antisense inhibition of gene expression in cells by obgonucleotides incorporating locked nucleic acids effect of mRNA target sequence and chimera design. Nucleic Acids Res. 2002 30 5160-5167. 

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