Strands
The RNA endonuclease Dicer plays a role in aiding RISC action by providing the initial RNA material to activate the complex as well as the first RNA substrate molecule. When the Dicer, which has endonuclease activity against dsRNA and pre-miRNAs, cleaves a pre-miRNA stem-loop or a dsRNA, a 20- to 25-base-pair double-stranded RNA fragment is formed with a two-nucleotide 3' overhang at each end.
- One strand is integrated into the RISC complex. This strand is known as the guide strand and is selected by the argonaute protein, the catalytically active RNase in the RISC complex, on the basis of the thermodynamic stability of the 5' end. The strand with a less thermodynamically stable 5' end is loaded into the RISC complex.
- The remaining strand, known as the anti-guide or passenger strand, is degraded as a RISC complex substrate.
Read more about this topic: RNA-induced Silencing Complex
Famous quotes containing the word strands:
“Writing fiction has developed in me an abiding respect for the unknown in a human lifetime and a sense of where to look for the threads, how to follow, how to connect, find in the thick of the tangle what clear line persists. The strands are all there: to the memory nothing is ever really lost.”
—Eudora Welty (b. 1909)