Final answer:
miRNAs and siRNAs are involved in the RNAi process where miRNAs inhibit translation or induce mRNA cleavage and siRNAs always lead to mRNA cleavage. lncRNAs can inhibit transcription and have various other functions in gene silencing.
Step-by-step explanation:
miRNAs, siRNAs, and lncRNAs all play vital roles in mediating gene silencing, each with their distinct mechanisms. miRNAs and siRNAs are involved in the RNA interference (RNAi) pathway. miRNAs are usually not completely complementary to the target mRNA, which leads to the inhibition of translation, but they can also induce cleavage if they are fully complementary. siRNAs are fully complementary to their target mRNA and lead to its cleavage after binding to the RNA-induced silencing complex (RISC).
Gene silencing can be summarized through the following actions: siRNAs and miRNAs after being processed by Dicer, are incorporated into the RISC where siRNAs tend to lead to mRNA cleavage, while miRNAs can inhibit translation or less frequently induce mRNA cleavage. lncRNAs have diverse roles that can include modulation of transcription rather than the mRNA-based mechanisms of siRNAs and miRNAs.