Solutions For An Introduction to Genetic Analysis Chapter 8 Problem 9P

Antisense technology is a form of gene silencing, which blocks expression of genes by introducing RNA (ribonucleic acid) that is complementary to the gene’s mRNA transcript. RNA, which is introduced, is known as antisense RNA.

The antisense RNA attaches to the sense mRNA (messenger ribonucleic acid). The result is a double-stranded RNA. The ribosome cannot read the codons in the double-stranded RNA. Hence, the translation does not occur. Therefore, the expression of the genes is silent.

RNA interference:

It is a mechanism that cells use to inhibit the expression of any particular gene, either by discontinuing translation process of any mRNA. This can be achieved by using micro-RNAs (miRNAs). Alternatively, this can also be achieved by degrading specific mRNA by targeting it with small interfering RNA (siRNA).

The production of siRNA from small hairpin RNAs (shRNAs) and long dsRNAs is catalyzed by the enzyme Dicer. The siRNAs can also be integrated into the cell via a process called transfection. These RNAs have the ability to knockdown the expression of any gene with a complementary sequence. Hence, they can be used as an important tool in the validation of gene function and in drug targeting in the era of post-genomic.

The activity of the siRNA majorly depends on its binding ability to RISC. Once it binds to RISC, unwinding of double strand RNA takes place and is followed by the cleavage of the sense strand. This is achieved by the action of endonucleases on it. The remaining anti-sense strand will direct the RISC factor towards mRNA for blocking its transcription and therefore silencing it.