Document Detail


Physical and functional coupling of RNA-dependent RNA polymerase and Dicer in the biogenesis of endogenous siRNAs.
MedLine Citation:
PMID:  17603500     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Many classes of small RNA (sRNA) involved in RNA silencing are generated by double-stranded RNA (dsRNA) processing. Although principles of sRNA biogenesis have emerged, newly identified classes of sRNAs have features that suggest additional biogenesis mechanisms. Tetrahymena thermophila expresses one such class, comprising sRNAs of 23 and 24 nucleotides (nt) with an absolute strand bias in accumulation. Here we demonstrate sRNA production by the T. thermophila Dicer Dcr2 and the RNA-dependent RNA polymerase Rdr1, which purifies as a multisubunit RNA-dependent RNA polymerase complex (RDRC). Dcr2 and RDRC interact, stimulating Dcr2 activity. Moreover, Dcr2 specificity is influenced by RDRC beyond this physical interaction, as Dcr2 generates discrete 23- and 24-nt sRNAs only from dsRNA with a 5'-triphosphate. These findings suggest that sRNA strand bias arises from Dcr2 processing polarity, conferred by physical and functional coupling of RDRC and Dicer enzymes.
Authors:
Suzanne R Lee; Kathleen Collins
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-01
Journal Detail:
Title:  Nature structural & molecular biology     Volume:  14     ISSN:  1545-9993     ISO Abbreviation:  Nat. Struct. Mol. Biol.     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-07-05     Completed Date:  2007-09-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101186374     Medline TA:  Nat Struct Mol Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  604-10     Citation Subset:  IM    
Affiliation:
Department of Molecular and Cell Biology, University of California - Berkeley, 142 Life Sciences Addition 3200, Berkeley, California 94720-3200, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Genes, Protozoan
Molecular Sequence Data
Protozoan Proteins / chemistry*,  genetics,  metabolism
RNA Replicase / chemistry*,  genetics,  metabolism
RNA, Protozoan / biosynthesis*
RNA, Small Interfering / biosynthesis*,  chemistry
Ribonuclease III / chemistry*,  metabolism
Substrate Specificity
Tetrahymena thermophila / enzymology*
Chemical
Reg. No./Substance:
0/Protozoan Proteins; 0/RNA, Protozoan; 0/RNA, Small Interfering; EC 2.7.7.48/RNA Replicase; EC 3.1.26.3/Ribonuclease III

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  RS domain-splicing signal interactions in splicing of U12-type and U2-type introns.
Next Document:  Irreversible cell-cycle transitions are due to systems-level feedback.