Home ＞GCOE Researchers ＞Kenzo NAKAMURA

GCOE Researchers

Kenzo NAKAMURA

Affiliation
/Position		 Graduate School of Bioagricultural Sciences, Department of Biological Mechanisms and Functions, Professor
Doctorate Doctor of Agriculture
Research interests Plant molecular biology, molecular mechanisms that control vegetative storage function in plants
address kenzo＠agr.nagoya-u.ac.jp
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+81-52-789-4095
  Laboratory

Outline of research

Vegetative storage capacity at the sink site of an individual plant is largely dependent on the activity at the source site. We have conducted studies on the molecular mechanisms involved in the regulation of vegetative storage function at the sink site.

We first discovered that sugar nutrition signals, which are common over plant species, play an important role in regulating gene expression to stimulate synthesis of storage proteins and starch (Plant Mol. Biol., 1990; Plant Phys., 1991). We demonstrated that induction of gene expression related to vegetative storage in response to sugars involves the Ca2+-dependent signal transduction system and protein phosphorylation mediated by a plant-specific CDPK (Plant J., 1995; Plant Phys., 1995). Furthermore, we identified cis-regulatory sequences involved in the transcriptional response to sugar control (Plant Mol. Biol., 2001). In parallel, we conducted research to elucidate the mechanism of selective transport of storage proteins to the vacuole within vegetative tissue. We developed an experimental system using genetic transformation of cultured tobacco cells, which is currently widely used worldwide. Using this system, we identified a vacuole targeting signal for protein (J. Biol. Chem., 1990; PNAS, 1991; Plant Phys., 1993), and demonstrated, for the first time, that plant cells have more than one protein transport pathways to the vacuole (J. Cell Biol., 1995; Plant Cell, 1997).

To analyze the mechanisms of the response to sugar nutrition signals, we exploited Arabidopsis genetics to isolate mutants in sugar signal response (Plant J., 1997; Plant Phys., 1997). Combining large-scale mutant screening using a luminescent reporter, activation tagging, and global transcriptome analysis, we have recently discovered transcription factors involved in the regulation of oil storage in seeds by controlling the expression of sugar response genes and the distribution of sugar carbon sources into fatty acids (Plant Cell Phys., 2005); we have also discovered genes involved in suppression of seed maturation program after germination and the switch to vegetative growth (Figure; Plant Phys., 2005; PNAS, 2007). Also, we identified new control systems related to seed size regulation (PNAS, 2005; Plant Cell Phys., 2006).

References

  1. Kojima H. et al. (2007) Sugar-inducible expression of nucleolin-1 gene of Arabidopsis thaliana and its role in ribosome synthesis, growth, and development. Plant J., 49: 1053-1063 (2007).
  2. Tsukagoshi H. et al. (2007) Two B3 domain transcriptional repressors prevent sugar-inducible expression of seed maturation genes in Arabidopsis seedlings. Proc. Natl. Acad. Sci. USA, 104: 2543-2547.
  3. Yoine M. et al. (2006) Arabidopsis UPF1 RNA helicase for nonsense-mediated mRNA decay is involved in seed size control and is essential for growth. Plant Cell Physiol., 47: 572-580.
  4. Yoine M. et al. (2006) The lba1 mutation of UPF1 RNA helicase involved in nonsense-mediated mRNA decay causes pleiotropic phenotypic changes and altered sugar signaling in Arabidopsis. Plant J., 47: 49-62.
  5. Inagaki S. et al. (2006) Arabidopsis TEBICHI with helicase and DNA polymerase domains is required for regulated cell division and differentiation in meristem. Plant Cell, 18: 879-892.
  6. Masaki T. et al. (2005) Activation tagging of a gene for a protein with novel class of CCT-domain activates expression of a subset of sugar-inducible genes in Arabidpsis thaliana. Plant J., 43: 142-152.
  7. Tsukagoshi H. et al. (2005) Analysis of sugar response mutant of Arabidopsis thaliana identified a novel B3 domain protein with the EAR motif that functions as an active transcriptional repressor. Plant Physiol., 138: 675-685.
  8. Ohto M. et al. (2005) Control of seed mass by APETALA2. Proc. Natl. Acad. Sci. USA, 102: 3123-3128.
  9. Shimizu M. et al. (2005) Experimental determination of proline hydroxylation and hydroxyproline arabinogalactoslation motifs in secretory proteins. Plant J., 42: 877-889.
  10. Suzuki T. et al. (2004) A novel Arabidopsis gene TONSOKU is required for proper cell arrangement in root and shoot apical meristems. Plant J., 38: 673-684.

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