{Reference Type}: Journal Article
{Title}: The guide-RNA sequence dictates the slicing kinetics and conformational dynamics of the Argonaute silencing complex.
{Author}: Wang PY;Bartel DP;
{Journal}: Mol Cell
{Volume}: 84
{Issue}: 15
{Year}: 2024 Aug 8
{Factor}: 19.328
{DOI}: 10.1016/j.molcel.2024.06.026
{Abstract}: The RNA-induced silencing complex (RISC), which powers RNA interference (RNAi), consists of a guide RNA and an Argonaute protein that slices target RNAs complementary to the guide. We find that, for different guide-RNA sequences, slicing rates of perfectly complementary bound targets can be surprisingly different (>250-fold range), and that faster slicing confers better knockdown in cells. Nucleotide sequence identities at guide-RNA positions 7, 10, and 17 underlie much of this variation in slicing rates. Analysis of one of these determinants implicates a structural distortion at guide nucleotides 6-7 in promoting slicing. Moreover, slicing directed by different guide sequences has an unanticipated, 600-fold range in 3'-mismatch tolerance, attributable to guides with weak (AU-rich) central pairing requiring extensive 3' complementarity (pairing beyond position 16) to more fully populate the slicing-competent conformation. Together, our analyses identify sequence determinants of RISC activity and provide biochemical and conformational rationale for their action.