TOP

Research Article

Split Viewer

Mol. Cells 2008; 26(3): 308-313

Published online January 1, 1970

© The Korean Society for Molecular and Cellular Biology

Cleavage of the Star Strand Facilitates Assembly of Some MicroRNAs into Ago2-containing Silencing Complexes in Mammals

Chanseok Shin

Abstract

In animals, microRNAs (miRNAs) and small interfering RNAs (siRNAs) repress expression of protein coding genes by assembling distinct RNA-induced silencing complexes (RISCs). It has previously been shown that passenger-strand cleavage is the predominant mechanism when siRNA duplexes are loaded into Argonaute2 (Ago2)-containing RISC, while an unwinding bypass mechanism is favored for miRNA duplexes with mismatches. Here I present experimental data indicating that some mammalian miRNAs are assembled into Ago2-containing RISC by cleaving their corresponding miRNA star strands. This phenomenon may depend on the secondary structure near the scissile phosphate of the miRNA duplex. In addition, I show that ATP is not required for star-strand cleavage in this process. Taken together, the data here provide insight into the miRNA-loading mechanisms in mammals.

Keywords Argonaute, microRNA, miRNA star-strand cleavage, passenger-strand cleavage, RISC

Article

Research Article

Mol. Cells 2008; 26(3): 308-313

Published online September 30, 2008

Copyright © The Korean Society for Molecular and Cellular Biology.

Cleavage of the Star Strand Facilitates Assembly of Some MicroRNAs into Ago2-containing Silencing Complexes in Mammals

Chanseok Shin

Abstract

In animals, microRNAs (miRNAs) and small interfering RNAs (siRNAs) repress expression of protein coding genes by assembling distinct RNA-induced silencing complexes (RISCs). It has previously been shown that passenger-strand cleavage is the predominant mechanism when siRNA duplexes are loaded into Argonaute2 (Ago2)-containing RISC, while an unwinding bypass mechanism is favored for miRNA duplexes with mismatches. Here I present experimental data indicating that some mammalian miRNAs are assembled into Ago2-containing RISC by cleaving their corresponding miRNA star strands. This phenomenon may depend on the secondary structure near the scissile phosphate of the miRNA duplex. In addition, I show that ATP is not required for star-strand cleavage in this process. Taken together, the data here provide insight into the miRNA-loading mechanisms in mammals.

Keywords: Argonaute, microRNA, miRNA star-strand cleavage, passenger-strand cleavage, RISC

Mol. Cells
May 31, 2023 Vol.46 No.5, pp. 259~328
COVER PICTURE
The alpha-helices in the lamin filaments are depicted as coils, with different subdomains distinguished by various colors. Coil 1a is represented by magenta, coil 1b by yellow, L2 by green, coil 2a by white, coil 2b by brown, stutter by cyan, coil 2c by dark blue, and the lamin Ig-like domain by grey. In the background, cells are displayed, with the cytosol depicted in green and the nucleus in blue (Ahn et al., pp. 309-318).

Share this article on

  • line
  • mail

Related articles in Mol. Cells

Molecules and Cells

eISSN 0219-1032
qr-code Download