2001 Fiscal Year Final Research Report Summary
Single-molecule imaging of processing and transport of mRNA within a living cell
| Project/Area Number |
11480196
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biophysics
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| Research Institution | Waseda University |
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Principal Investigator |
FUNATSU Takashi Waseda University, School of Science and Engineering, Associate Professor, 理工学部, 助教授 (00190124)
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| Co-Investigator(Kenkyū-buntansha) |
TANI Tokio Kumamoto University, Faculty of Science, Professor, 理学部, 教授 (80197516)
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| Project Period (FY) |
1999 – 2001
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| Keywords | mRNA / single-molecule imaging / fluorescence microscopy / スプライシング |
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| Research Abstract |
Messenger RNA is transcribed and processed in the nucleus and transported to the cytoplasm. In order to clarify the molecular mechanism of these processes, we have developed video-rate confocal microscopy that enabled us to visualize single fluorescence molecules. Movement of individual mRNA molecules within living cell was visualized by this microscopy to distinguish whether mRNA is directed by active transport or moving around by diffusion. For this purpose, Cy3-labeled truncated human β-globin mRNA molecules were prepared in vitro and micro-injected into the nucleus of Xenopus A6 cell. Cy3-labeled mRNA molecules could be observed except nucleoli, indicating that mRNA could access most of the space, excluding nucleoli, in the nucleus. Some population of mRNA moved around in diffusion, and some remained stationary. Statistical analysis of individual mRNA trajectories revealed that about 50 % of mRNA is moving at the diffusion constant of 0.2[μm^2/s]. This value is about 1/40 of that in solution (9 [μm2/s]). Our results support the mechanism that mRNA reach nuclear pores by diffusion process.
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