理工学部

藤原 誠

フジワラ マコト  (Fujiwara Makoto)

基本情報

所属
上智大学 理工学部物質生命理工学科 教授
学位
学士(東京大学)
修士(東京大学)
博士(農学)(東京大学)

研究者番号
90332345
J-GLOBAL ID
200901000526942076
researchmap会員ID
5000099166

微生物 (共生体オルガネラ) の分化・形態形成に惹かれ研究をしてきた。
1994–1997年 糸状菌の形態形成におけるキチン合成酵素の役割に関する分子遺伝学的研究
1997–2000年 葉緑体RNAポリメラーゼσ因子に関する研究
2000–2010年 葉緑体分裂制御に関する研究
2010– (現在)  植物オルガネラの形態ダイナミクス

(研究テーマ)
(1) 色素体の細胞生物学的解析
(2) 緑藻類の細胞形態学的解析


論文

 56
  • Alvin Sanjaya, Ryo Nishijima, Yuki Fujii, Makoto Asano, Kotaro Ishii, Yusuke Kazama, Tomoko Abe, Makoto T. Fujiwara
    Frontiers in Plant Science 15 2024年9月  査読有り最終著者責任著者
    Pre-mRNA splicing is a fundamental process in eukaryotic gene expression, and the mechanism of intron definition, involving the recognition of the canonical GU (5’-splice site) and AG (3’-splice site) dinucleotides by splicing factors, has been postulated for most cases of splicing initiation in plants. Splice site mutations have played crucial roles in unraveling the mechanism of pre-mRNA splicing in planta. Typically, splice site mutations abolish splicing events or activate one or more cryptic splice sites surrounding the mutated region. In this report, we investigated the splicing pattern of the EGY1 gene in an Ar-ion-induced egy1-4 allele of Arabidopsis thaliana. egy1-4 has an AG-to-AC mutation in the 3′-end of intron 3, along with 4-bp substitutions and a 5-bp deletion in adjacent exon 4. RT-PCR, cDNA cloning, and amplicon sequencing analyses of EGY1 revealed that while most wild-type EGY1 mRNAs had a single splicing pattern, egy1-4 mRNAs had multiple splicing defects. Almost half of EGY1 transcripts showed ‘intron retention’ at intron 3, while the other half exhibited activation of 3’ cryptic splice sites either upstream or downstream of the original 3’-splice site. Unexpectedly, around 8% of EGY1 transcripts in egy1-4 exhibited activation of cryptic 5′-splice sites positioned upstream of the authentic 5’-splice site of intron 3. Whole genome resequencing of egy1-4 indicated that it has no other known impactful mutations. These results may provide a rare, but real case of activation of cryptic 5’-splice sites by downstream 3’-splice site/exon mutations in planta.
  • Makoto T Fujiwara, Yasushi Yoshioka, Yusuke Kazama, Tomonari Hirano, Yasuo Niwa, Takashi Moriyama, Naoki Sato, Tomoko Abe, Shigeo Yoshida, Ryuuichi D Itoh
    Plant Physiology 2024年9月  査読有り筆頭著者責任著者
  • Kanae Matsuoka, Hiroko Kubotera, Rina Miyazaki, Shota Moriyama, Makoto T Fujiwara, Ryuuichi D Itoh
    International Journal of Plant Biology 2024年1月  査読有り
  • Akane Yamagishi, Yuki Egoshi, Makoto T Fujiwara, Noriyuki Suzuki, Tohru Taniguchi, Ryuuichi D Itoh, Yumiko Suzuki, Yoshiro Masuyama, Kenji Monde, Toyonobu Usuki
    CHEMISTRY – A EUROPEAN JOURNAL (Weinheim an der Bergstrasse, Germany) 29(8) e202203396 2023年2月7日  査読有り責任著者
    Foeniculoxin is a major phytotoxin produced by Italian strains of Phomopsis foeniculi. The first total synthesis is described utilizing the ene reaction and Sonogashira cross-coupling reaction as key steps. The absolute configuration of the C6' was determined using chiral separation and advanced Mosher's method. The phytotoxicity of the synthesized compound was demonstrated via syringe-based infiltration into Chenopodium album and Arabidopsis thaliana leaves. Synthetic foeniculoxin induced various defects in A. thaliana leaf cells before lesion formation, including protein leakage into the cytoplasm from both chloroplasts and mitochondria and mitochondrial rounding and swelling. Furthermore, foeniculoxin and the antibiotic hygromycin B caused similar agglomeration of mitochondria around chloroplasts, highlighting this event as a common component in the early stages of plant cell death.
  • Ryuuichi D. Itoh, Kohdai P. Nakajima, Shun Sasaki, Hiroki Ishikawa, Yusuke Kazama, Tomoko Abe, Makoto T. Fujiwara
    PLANT JOURNAL 107(1) 237-255 2021年7月  査読有り最終著者
    Stromules are dynamic membrane-bound tubular structures that emanate from plastids. Stromule formation is triggered in response to various stresses and during plant development, suggesting that stromules may have physiological and developmental roles in these processes. Despite the possible biological importance of stromules and their prevalence in green plants, their exact roles and formation mechanisms remain unclear. To explore these issues, we obtained Arabidopsis thaliana mutants with excess stromule formation in the leaf epidermis by microscopy-based screening. Here, we characterized one of these mutants, stromule biogenesis altered 1 (suba1). suba1 forms plastids with severely altered morphology in a variety of non-mesophyll tissues, such as leaf epidermis, hypocotyl epidermis, floral tissues, and pollen grains, but apparently normal leaf mesophyll chloroplasts. The suba1 mutation causes impaired chloroplast pigmentation and altered chloroplast ultrastructure in stomatal guard cells, as well as the aberrant accumulation of lipid droplets and their autophagic engulfment by the vacuole. The causal defective gene in suba1 is TRIGALACTOSYLDIACYLGLYCEROL5 (TGD5), which encodes a protein putatively involved in the endoplasmic reticulum (ER)-to-plastid lipid trafficking required for the ER pathway of thylakoid lipid assembly. These findings suggest that a non-mesophyll-specific mechanism maintains plastid morphology. The distinct mechanisms maintaining plastid morphology in mesophyll versus non-mesophyll plastids might be attributable, at least in part, to the differential contributions of the plastidial and ER pathways of lipid metabolism between mesophyll and non-mesophyll plastids.

MISC

 9
  • Sanjaya A, Muramatsu R, Sato S, Suzuki M, Sasaki S, Ishikawa H, Fujii Y, Asano M, Itoh R, Kanamaru K, Ohbu S, Abe T, Kazama Y, Fujiwara M
    RIKEN Accelerator Progress Report 55 S30 2022年12月  査読有り
  • Sanjaya A, Kazama Y, Ishii K, Ohbu S, Abe T, Fujiwara M
    RIKEN Accelerator Progress Report 54 178 2021年10月  査読有り
  • Morita R, Nakagawa M, Takehisa H, Hayashi Y, Ichida H, Usuda S, Ichinose K, Abe H, Shirakawa Y, Sato T, Fujiwara M, Itoh R, Abe T
    RIKEN Accelerator Progress Report 50 272-272 2017年10月  査読有り
  • Kazama Y, Fujiwara MT, Takehisa H, Ohbu S, Saito H, Ichida H, Hayashi Y, Abe T
    RIKEN Accelerator Progress Report 46 264-264 2013年11月  査読有り
  • 藤原 誠, 伊藤 竜一, 森山 崇, 丹羽 康夫, 佐藤 直樹, 阿部 知子, 吉田 茂男
    日本植物生理学会年会およびシンポジウム 講演要旨集 2009 145-145 2009年  
    アミロプラストはデンプンの合成と蓄積に特化した色素体である。葉緑体と同様に二重包膜を持ち、細胞内で二分裂によって増殖する。従来、色素体分裂に関する分子レベルの研究は主に葉緑体を用いて行われてきた。しかし、「葉緑体モデル」が非緑色色素体にも当てはまるか否かについては、まだ十分に検証されていない。本研究ではシロイヌナズナのアミロプラスト増殖機構に着目した。<br> 近年、我々はアミロプラスト分化のダイナミクス解析にシロイヌナズナの珠皮が有効であることを見出している(昨年度大会発表)。4種の葉緑体分裂異常変異体(arc5arc6minDminE)及びストロマ局在性蛍光タンパク質発現系統を用いて珠皮アミロプラストの分裂表現型を解析したところ、葉緑体分裂位置異常を引き起こすminD変異や分裂アレストをもたらすarc5変異は、アミロプラスト増殖に殆ど影響しないことが判った。一方、葉緑体分裂が阻害されるminE変異体やarc6変異体では、細胞中にさまざまな大きさのアミロプラストが形成されていた。これらの結果は、アミロプラストと葉緑体の分裂制御は大きく異なることを示唆している。今回さらに、minEarc6両変異体において、FtsZリングがストロミュール中に形成される一種の分裂位置異常が起こっていることが判明した。本発表では、色素体複製におけるストロミュールの役割について議論する。

書籍等出版物

 4

講演・口頭発表等

 51

共同研究・競争的資金等の研究課題

 17

社会貢献活動

 1