Question

RNA knockdown has become a powerful tool in the arsenal of methods used to repress gene expression. Briefly describe how gene expression can be knocked down. What effect would introducing siRNAs to TSC1 have on human cells?

Answer 1

Gene knockdown is a proces in which expression of gene is reduced either modifications in DNA or either targetting RNA. RNA knock down is used to target RNA , so RNA is not translated or degraded and leads to decreased expression of gene.

RNA interference ( RNAi) is used to silencing genes by way of mRNA degradation.

Here small double-stranded interfering RNAs (siRNA) into the cytoplasm. These Si RNA can originate from inside the cell or they can be provided exogenously into the cell.

Inside the cell, siRNAs are processed by the RISC complex (RNA-induced silencing complex) . Now the generated single stranded siRNA is used to the target mRNA to be silenced. In this process RISC uses the siRNA as a template and locate the target mRNA. Than this RISC localizes this si RNA to  target mRNA, and this RNA is cleaved by a ribonuclease lead to decreased expression of gene by degradtion of RNA.

For better understanding whole procedure has been explained below.

TSC1 interact with TSC2 form dimer , this negative regulate mTOR pathway thus regulating ce proliferation it act as tumor supressor gene.

If we silenc TSC1 using RNAi , there will be unopposed cell proliferation lead to increase risk of tumor generation.