Presentation Information
[P02-169]Visualization and regulation of parasynchronous mitotic entry in multinucleated filamentous fungi
○Hina Tanuma1, Takuya Katayama2, Kan Tanaka3, Jun-ichi Maruyama1 (1. The Univ. of Tokyo (Japan), 2. NIID (Japan), 3. Science Tokyo (Japan))
Keywords:
filamentous fungi,Aspergillus oryzae,multinucleate,mitosis
Filamentous fungi are characterized by multinucleated cells in which multiple nuclei share a common cytoplasm. These nuclei can undergo either synchronous or asynchronous mitosis1); however, the spatiotemporal regulation of mitotic entry in multinucleated filamentous fungi remains unclear. In the industrial filamentous fungus Aspergillus oryzae, we monitored mitotic entry by tracking the diffusion of nuclear-localized EGFP into the cytoplasm at mitotic onset, consistent with partial disassembly of nuclear pore complexes. Time-lapse imaging revealed that mitotic entry was not fully synchronized but instead occurred parasynchronously, typically initiating in a nucleus on the hyphal tip side and propagating toward the basal region.
Given a previous report demonstrating that an F-box protein coordinates replication timing between chloroplast and nuclear genomes in the red alga Cyanidioschyzon merolae2), we examined the role of the evolutionarily conserved F-box protein FbxA in the cell cycle of A. oryzae. Deletion of the fbxA gene resulted in the near-simultaneous mitotic entry of multiple nuclei on the hyphal tip side, suggesting that FbxA contributes to specifying the subcellular site of parasynchronous mitotic initiation. We are currently investigating the signals hypothesized to spatiotemporally regulate FbxA function during mitosis.
1) Gladfelter et al. (2006) Curr. Opin. Microbiol. 9, 547–552.
2) Kobayashi et al. (2011) Nat. Cell Biol. 13, 483–487.
Given a previous report demonstrating that an F-box protein coordinates replication timing between chloroplast and nuclear genomes in the red alga Cyanidioschyzon merolae2), we examined the role of the evolutionarily conserved F-box protein FbxA in the cell cycle of A. oryzae. Deletion of the fbxA gene resulted in the near-simultaneous mitotic entry of multiple nuclei on the hyphal tip side, suggesting that FbxA contributes to specifying the subcellular site of parasynchronous mitotic initiation. We are currently investigating the signals hypothesized to spatiotemporally regulate FbxA function during mitosis.
1) Gladfelter et al. (2006) Curr. Opin. Microbiol. 9, 547–552.
2) Kobayashi et al. (2011) Nat. Cell Biol. 13, 483–487.
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