| Budget Amount *help |
¥4,020,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
Eukaryotic chromatin is microscopically classified into heterochromatin and euchromatin. Although specific proteins such as HP1 (heterochromatin protein 1) give rise to heterochromatin in animal cells, the factors relating to different chromatin states in plant cells remain unclear. So, in this study, we tried to clarify the major factor to determine the chromatin differentiation between heterochromatin and euchromatin in the case of pollen. Because, the generative nucleus within pollen has highly condensed chromatin (heterochromatin), whereas the vegetative nucleus contains diffuse chromatin (euchromatin).
As a result, it was demonstrated that gHl, which had been identified as male gametic nucleus-highly concentrated histone H1, showed a remarkable polarization just after the first microspore mitosis. Namely, gHl was only detected in the generative nucleus and largely accumulated in the male gametic nucleus during pollen development. On the other hand, gH1 was barely detected in the vegetative nucleus. Next, two histone H1 genes, gH1 and somatic type-histone H1 (sH1), were isolated and expression analysis was done by RT-PCR method. As a result, while the expression of sH1 came to a stop during pollen maturation, the expression of gH1 remarkably increased from just before the first microspore mitosis. Accordingly, gH1 was assumed as a factor of heterochromatization. The function of gH1 is now investigating by gene transfer into somatic cells with GFP.
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