EnsiöRNAs

EnsiöRNAs, also known as primary microRNAs or pri-miRNAs, are the initial transcripts generated from microRNA genes. These long, precursor molecules undergo processing to eventually yield mature microRNAs, which are crucial regulators of gene expression. Pri-miRNAs are characterized by their hairpin-like secondary structure, which is essential for their recognition and processing by specific enzymes.

The processing of pri-miRNAs occurs in two main steps. First, a nuclear enzyme complex called Drosha, along with its cofactor DGCR8, cleaves the pri-miRNA to produce a shorter precursor molecule called pre-miRNA. This pre-miRNA, also featuring a hairpin structure, is then exported from the nucleus to the cytoplasm. In the cytoplasm, another enzyme, Dicer, further processes the pre-miRNA, excising the hairpin loop and generating a double-stranded RNA duplex.

One strand of this duplex, the mature miRNA, is then incorporated into the RNA-induced silencing complex (RISC). The RISC-miRNA complex guides the degradation of target messenger RNA (mRNA) molecules or inhibits their translation into proteins, thereby downregulating gene expression. The precise mechanisms of pri-miRNA processing and the factors influencing it are areas of ongoing research, with implications for understanding cellular development, disease, and therapeutic strategies.