Poster: Organelle Biogenesis

Abs # 1137: Mitochondrial division in Arabidopsis is performed by two dynamin-like proteins; ADL2a and ADL2b.

Presenter:	Arimura, Shin-ichi , arimura@mail.ecc.u-tokyo.ac.jp
Authors	Arimura, Shin-ichi  (A)   Tsutsumi, Nobuhiro  (A)
Affiliations:	(A): The University of Tokyo

Plant mitochondria divide to maintain themselves during cell proliferation. Previously, we characterized an Arabidopsis dynamin-like protein, ADL2b, that functions in this process (Arimura and Tsutsumi 2002). The Arabidopsis genome has another highly homologous gene, ADL2a, which has been reported to localize in chloroplasts (Kang et al., 1998). To confirm the localizations of ADL2a, we constructed GFP fusion proteins with the N-terminal portions of these proteins. However, in our experiment, no signals were detected in chloroplasts, but signals were detected in the cytoplasm. When the full length of ADL2a was attached to GFP, a strong GFP signal was localized at the tips and at the constriction sites of mitochondria. This localization pattern was the same as that of ADL2b. Furthermore, overexpression of ADL2a that had a point mutation in its GTPase domain caused mitochondrial elongation. We think it means that normal division process is not functioning properly. Consequently, we suggest that not only ADL2b but also ADL2a is involved in the division of plant mitochondria.