Molecular Biology RNA

Question: RNAi is a fairly new tool that molecular biologist use to inhibit gene expression. RNAi can inhibit gene expression in two ways. Please describe the principle of RNAi and the two ways in which RNAi can inhibit gene expression. Answer: Principle of RNAi RNAi refers to RNA interference. It is a process of gene silencing, which is sequence-specific and occurs at the post-transcriptional level (Allison, 2007). It involves the creation of short molecules of RNA that are complementary to endogenous mRNA. Two ways of inhibition of gene expression by RNA The cleavage of double-stranded RNA occurs by Dicer involving an ATP-dependent reaction resulting in the formation of RNA-inducing silencing complex (RISC) (Castel Martienssen, 2013). The miRNA precursor is cleaved by Dicer to produce 22 nucleotides miRNA. The single stranded miRNAs gets incorporated into RISC, followed by recognition of target and final inhibition (Fellmann Lowe, 2014). Mechanism of RNA interference (Allison, 2007) References: Allison, L. A. (2007). Fundamental Molecular Biology. Castel, S. E., Martienssen, R. A. (2013). RNA interference in the nucleus: roles for small RNAs in transcription, epigenetics and beyond.Nature Reviews Genetics,14(2), 100-112. Fellmann, C., Lowe, S. W. (2014). Stable RNA interference rules for silencing.Nature cell biology,16(1), 10-18.