Enzymatic properties and functional divergence of plant Dicers

2014 Fiscal Year Final Research Report

• Project/Area Number: 24570044
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Plant molecular biology/Plant physiology
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: FUKUHARA Toshiyuki 東京農工大学, (連合)農学研究科(研究院), 教授 (90228924)
• Co-Investigator(Renkei-kenkyūsha): HABU Yoshiki 独立行政法人農業生物資源研究所, 農業先端ゲノム研究センター, 主任研究員 (80266915) ; YOSHIKAWA Manabu 独立行政法人農業生物資源研究所, 植物・微生物間相互作用研究ユニット, 主任研究員 (80391564) ; ISHII Kazuo 東京農工大学, 大学院農学研究院, 教授 (60449238) ; ISHIKAWA Hideaki 東京農工大学, 大学院農学研究院, 助教 (80625715) ; IZUMIKAWA Keiichi 東京農工大学, 大学院農学研究院, 助教 (60625713) ; KOZAKI Toshinori 東京農工大学, 大学院農学研究院, 助教 (60442828)
• Research Collaborator: NAGANO Hideaki ; SETA Atsushi
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ダイサー / シロイヌナズナ / ＤＣＬ３ / ＤＣＬ４ / ２本鎖ＲＮＡ / 小分子ＲＮＡ / 基質特異性

Outline of Final Research Achievements

A model plant Arabidopsis thaliana has four distinct Dicer-like proteins (DCL1 - DCL4), which produce small RNAs of 21 to 24 nucleotides (nt) in length from long double-stranded RNA (dsRNA) precursors. DCL3 products, 24 nt siRNAs, function in RNA-directed DNA methylation, whereas DCL4 products, 21 nt siRNAs, function in RNA interference. To reveal how these four Dicers individually recognize long dsRNAs as substrates, in this study we biochemically characterized DCL3 and DCL4. DCL3 preferentially cleaves short dsRNAs with 5’ phosphorylated adenosine or uridine and a 1 or 2 nt 3’ overhang, whereas DCL4 cleaves long dsRNAs with blunt ends. Inorganic phosphate and NaCl enhance DCL3 activity but inhibit DCL4 activity. These results demonstrated that the substrate specificities of DCL3 and DCL4 differ distinctly, just as their in vivo functions differ.

Free Research Field

植物細胞分子生物学