The Inside-Out Mechanism of Dicers from Budding Yeasts

Journal Article · Sat Dec 31 04:00:00 EST 2011 · Cell

DOI:https://doi.org/10.1016/j.cell.2011.06.021· OSTI ID:1041723

Weinberg, D; Nakanishi, K; Patel, D; Bartel, D

The Dicer ribonuclease III (RNase III) enzymes process long double-stranded RNA (dsRNA) into small interfering RNAs (siRNAs) that direct RNA interference. Here, we describe the structure and activity of a catalytically active fragment of Kluyveromyces polysporus Dcr1, which represents the noncanonical Dicers found in budding yeasts. The crystal structure revealed a homodimer resembling that of bacterial RNase III but extended by a unique N-terminal domain, and it identified additional catalytic residues conserved throughout eukaryotic RNase III enzymes. Biochemical analyses showed that Dcr1 dimers bind cooperatively along the dsRNA substrate such that the distance between consecutive active sites determines the length of the siRNA products. Thus, unlike canonical Dicers, which successively remove siRNA duplexes from the dsRNA termini, budding-yeast Dicers initiate processing in the interior and work outward. The distinct mechanism of budding-yeast Dicers establishes a paradigm for natural molecular rulers and imparts substrate preferences with ramifications for biological function.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1041723
• Report Number(s): BNL--97401-2012-JA
• Journal Information: Cell, Journal Name: Cell Journal Issue: 2 Vol. 146; ISSN 0092-8674; ISSN CELLB5
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
BIOLOGICAL FUNCTIONS
CRYSTAL STRUCTURE
DIMERS
DISTANCE
ENZYMES
INTERFERENCE
LENGTH
PROCESSING
RESIDUES
RNA
RNA-ASE
SUBSTRATES
YEASTS