Question

Explain the process of RNAi and how it contributes to differential gene expression

Answer 1

RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression of certain targeted mRNAs ( typically by causing the destruction of specific mRNA molecules). RNAi is facilitated by two small RNA: miRNA and siRNA. These small RNA molecules bind to target mRNA and then either increase or decrease their activity by inhibiting translation.

This process is started by dicer enzyme that cleave long RNA strands into smaller double stranded siRNAs. So, RNA unwound to yield two single stranded RNA molecules, one is known as passenger strand and the other is called guide RNA. Guide RNA is combined into RNA induced silencing complex (RISC). Then, Guide RNA complementarily bind to mRNA molecule and then cleaved by argonaute-2, the catalytic component of RISC.

Gene expression is mainly maintained by miRNA. miRNAs repress translation, indulged in timing of morphogenesis, in regulation of development, , and maintenance of stem cells.