1999 Fiscal Year Final Research Report Summary
Investigation of genes involved in construction of the cell wall architecture in plants
| Project/Area Number |
09440269
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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 |
植物生理
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NISHITANI Kazuhiko Graduate School of Science, Tohoku University, professor, 大学院・理学研究科, 教授 (60164555)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOYAMA Ryusuke Graduate School of Science, Tohoku University, Research Associate, 大学院・理学研究科, 助手 (90302083)
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| Project Period (FY) |
1997 – 1999
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| Keywords | CELL WALL / XYLOGLUCAN / ENDOXYLOGLUCAN / CELL PLATE |
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| Research Abstract |
A fluoresceinyl xyloglucan oligomer was synthesized and used as a probe to visualize the activity of the cell wall to incorporate xyloglucan fragments into the cellulose/xyloglucan framework in tabacco BY-2 cells. The activity was significantly reduced in transformant cells in which the expression of endoxyloglucan transferase (EXGT) was severely suppressed by over-expression of the antisense EXGT-N1 mRNA. These results indicate the involvement of EXGT in the construction of the cellulose/xyloglucan framework.
To examine their translocation pathways, we traced its intracellular localization in tabacco BY-2 cells by means of GFP-fusion protein procedures as well as by indirect immunofluorescence. During interphase, the protein was extensively secreted into the apoplast via the endoplasmic reticulum (ER)-Golgi apparatus network. At prophase, the apoplast-direct transportation was diminished and the protein was accumulated in the ER-Golgi network domain located around the nucleus. As cytokinesis proceeded, the protein was exclusively located in the phragmoplast and eventually transported to the cell plate. On the other hand, levels of the EXGT-N1 mRNA remained mostly unchanged between the mitotic phase and interphase. These results indicate that the direction of membrane trafficking of secretory enzymes be precisely regulated in a cell-cycle-dependent manner.
To gain insight into functions of individual EXGT genes in plant, we screened DNA pools derived from 17000 T-DNA tag lines of Arabidopsis by means of PCR and DNA blot analyses. We found 7 independent T-DNA tag lines in which T-DNA had been inserted within or in the vicinity of any EXGT gene. Sequencing analyses have shown that these tag lines include insertion mutants deficient in EXGT-A2, XTR4 or XTR15 gene.
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