Minimization of universal oritatami system and its limit

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K19779
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 60:Information science, computer engineering, and related fields
• Research Institution: The University of Electro-Communications
• Principal Investigator: Seki Shinnosuke 電気通信大学, 大学院情報理工学研究科, 准教授 (30624944)
• Co-Investigator(Kenkyū-buntansha): Fazekas Szilard 秋田大学, 理工学研究科, 講師 (70725382)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: 分子自己組織化 / 共転写性フォールディング / チューリング完全性

Outline of Final Research Achievements

A single-stranded sequence of RNA folds upon itself into an intricate structure while being synthesized (transcribed) from a template DNA sequence. This phenomenon called cotranscriptional folding has been utilized to self-assemble an artificial structure. In order to develop this technology further for artificial general-purpose computations, the mathematical model “oritatami system (OS)” has been proposed. The OS is known to be Turing universal, that is, be capable of computing all computable functions, but the OS proposed to prove this universality was too complicated to be implemented in-vitro. In this project, we have engineered a drastically simpler Turing universal OS. We also approached the limit of simplification from the opposite side by discovering several conditions under which the OS loses the Turing universality.

Free Research Field

分子計算理論

Academic Significance and Societal Importance of the Research Achievements

分子工学の分野は近年劇的な進展を遂げ、様々な構造や計算機構をDNAの反応により実現することが可能になってきている。DNAはしかしその安定性ゆえに反応活性をあげるために環境温度の変化を必要とし、それがこれら技術の生体応用を難しくしている。本課題が取り扱うRNA共転写性フォールディング（CF）は、生体内での情報処理に欠かせない現象であり、2014年にGearyらは人工タイル構造をCFにより試験管内で自己組織化させることに成功した。本課題は数理モデルを用いてCFの計算能力を明らかにする。CF駆動の計算機が実現すれば例えば疾病の治癒プログラムを遺伝子に埋め込むことで生体内での自動治癒が可能となる。