Figure 1.

The functions of miRNA and lncRNA and the interaction of ncRNAs. Pre-miRNA is transported into the cytoplasm through exportin-5 and Ran-GTP where it is cleaved by Dicer and finally converted into mature miRNA. This double-stranded small RNA separates into two single strands. One strand from mature miRNA is loaded into the RISC that recruits target mRNA and initiates either translation inhibition or mRNA degradation. lncRNA acts as scaffolds, signals, decoys, guides, miRNA sponges, and enhancer RNAs. They can also contribute to the stability of mRNA. They can serve as downstream regulators of miRNA by acting as competing endogenous RNAs. circRNAs act as miRNA sponges or competing endogenous RNA.