Analysis of the tobacco rDNA spacer region and rRNA transcription
| Project/Area Number |
04640623
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | Kanazawa University |
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Principal Investigator |
YAKURA Kimitaka Kanazawa University Education Associate Professor, 教育学部, 助教授 (50166485)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1992: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | rDNA / plant rDNA / rDNA subrepeats / transcription initiation site / Nicotiana tabacum / タバコ / 転写開始点 / 反復配列 |
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| Research Abstract |
In this research, the author aimed to characterize structure of the tobacco rDNA spacer region and to establish in vitro rRNA transcription system using cell extract from tobacco cultured cells in order to know how the rRNA transcription is controlled in plant system.
First, nucleotide sequence of the tobacco (Nicotiana tabacum cv. putit Havana SR1) rDNA large intergenic spacer (IGS) was determined and following results were obtained. (1) A short motif of TATATAAGGGGG, which is well conserved at the rRNA transcription initiation site (TIS) among various plants, was found in near the center of the rDNA IGS.(2) About 440 bp domain immediately before the TIS was extremely rich in A or T (81% A+T content). This domain has sequence homology to the AT-rich counterparts of tomato and potato rDNAs. (3) Four types of subrepeats (referred to as subrepeat I, II, III and IV, respectively) were present in the tobacco rDNA IGS.Subrepeat I, lying upstream the AT-rich domain, basically consists of six 217-bp elements. But, four of the six elements were truncated at the 5' or 3' regions. On the other hand, subrepeat II, III and IV are located downstream the TIS.Subrepeat II has fifteen elements of a 121 bp segment separated each other by a element of subrepeat III (20 bp) or IV (14 bp).
Second, in order to establish in vitro transcription system for tobacco rDNA, the author has tried to prepare transcriptionally active whole cell extract from tobacco BY2 cells by several methods for two years. Unfortunately, any signals of in vitro transcription products were not yet detected on electrophoresed gels. It is possible that the BY2 whole-cell extract may contain high nuclease activity causing degradation of rDNA templates and/or RNA products. Therefore, the author is now planning to prepare the nuclear extract from protoplast BY2 cells.
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Report
(3 results)
Research Products
(1 results)
