Open AccessThe N-Terminal Domain That Distinguishes Yeast from Bacterial RNase III Contains a Dimerization Signal Required for Efficient Double-Stranded RNA Cleavage
Author(s) -
Bruno Lamontagne,
Annie Tremblay,
Sherif Abou Elela
Publication year - 2000
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.20.4.1104-1115.2000
Subject(s) - biology , ribonuclease iii , rna , rnase p , rnase h , microbiology and biotechnology , rna silencing , ribonucleoprotein , nuclease , cleavage (geology) , rnase mrp , endoribonuclease , biochemistry , rna interference , dna , gene , paleontology , fracture (geology)
Yeast Rnt1 is a member of the double-stranded RNA (dsRNA)-specific RNase III family identified by conserved dsRNA binding (dsRBD) and nuclease domains. Comparative sequence analyses have revealed an additional N-terminal domain unique to the eukaryotic homologues of RNase III. The deletion of this domain from Rnt1 slowed growth and led to mild accumulation of unprocessed 25S pre-rRNA. In vitro, deletion of the N-terminal domain reduced the rate of RNA cleavage under physiological salt concentration. Size exclusion chromatography and cross-linking assays indicated that the N-terminal domain and the dsRBD self-interact to stabilize the Rnt1 homodimer. In addition, an interaction between the N-terminal domain and the dsRBD was identified by a two-hybrid assay. The results suggest that the eukaryotic N-terminal domain of Rnt1 ensures efficient dsRNA cleavage by mediating the assembly of optimum Rnt1-RNA ribonucleoprotein complex.