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Visualization of a cytoskeleton-like FtsZ network in chloroplasts.

Kiessling J, Kruse S, Rensing SA, Harter K, Decker EL, Reski R - J. Cell Biol. (2000)

Bottom Line: It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton.Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure.As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term "plastoskeleton" for this newly described subcellular structure.

View Article: PubMed Central - PubMed

Affiliation: University of Freiburg, Plant Biotechnology, D-79104 Freiburg, Germany.

ABSTRACT
It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton. Recently, this belief was questioned by the finding that the bacterial cell division protein FtsZ resembles tubulin in sequence and structure and, thus, may be the progenitor of this major eukaryotic cytoskeletal element. Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure. Both their encoded proteins are imported into plastids and there, like in bacteria, they act on the division process in a dose-dependent manner. Whereas in bacteria FtsZ only transiently polymerizes to a ring-like structure, in chloroplasts we identified persistent, highly organized filamentous scaffolds that are most likely involved in the maintenance of plastid integrity and in plastid division. As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term "plastoskeleton" for this newly described subcellular structure.

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Inhibition of chloroplast division by high overexpression of FtsZ-GFP. Moss protonemata were analyzed by CLSM 10 d after protoplast transfection with expression plasmids FtsZ1-GFP (a and c), FtsZ2-GFP (b and d), or pFtsZ1(1–93)-GFP (e and f); (c) detail of a; (f) detail of e. a–c, and e and f, represent overlays of chlorophyll (red) and GFP (green) channel, in d only GFP channel is shown. Bars, 20 μm.
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Figure 4: Inhibition of chloroplast division by high overexpression of FtsZ-GFP. Moss protonemata were analyzed by CLSM 10 d after protoplast transfection with expression plasmids FtsZ1-GFP (a and c), FtsZ2-GFP (b and d), or pFtsZ1(1–93)-GFP (e and f); (c) detail of a; (f) detail of e. a–c, and e and f, represent overlays of chlorophyll (red) and GFP (green) channel, in d only GFP channel is shown. Bars, 20 μm.

Mentions: Like their bacterial progenitors, both Physcomitrella proteins acted in a dose-dependent manner on the division process despite the presence of the COOH-terminal GFP fusion domain. Low FtsZ-GFP levels (indicated by weak GFP fluorescence) led to an enhancement of the division process and resulted in plastids that were significantly reduced in size (Fig. 3). In contrast, high FtsZ levels (indicated by strong GFP fluorescence) blocked plastid division (Fig. 4, a–d), leading to undivided, abnormally large plastids closely resembling the PpftsZ1-knockout phenotype (Strepp et al. 1998). The reduction of plastid size in cells overexpressing FtsZ-GFP indicates that the recombinant proteins are functional in division.


Visualization of a cytoskeleton-like FtsZ network in chloroplasts.

Kiessling J, Kruse S, Rensing SA, Harter K, Decker EL, Reski R - J. Cell Biol. (2000)

Inhibition of chloroplast division by high overexpression of FtsZ-GFP. Moss protonemata were analyzed by CLSM 10 d after protoplast transfection with expression plasmids FtsZ1-GFP (a and c), FtsZ2-GFP (b and d), or pFtsZ1(1–93)-GFP (e and f); (c) detail of a; (f) detail of e. a–c, and e and f, represent overlays of chlorophyll (red) and GFP (green) channel, in d only GFP channel is shown. Bars, 20 μm.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169431&req=5

Figure 4: Inhibition of chloroplast division by high overexpression of FtsZ-GFP. Moss protonemata were analyzed by CLSM 10 d after protoplast transfection with expression plasmids FtsZ1-GFP (a and c), FtsZ2-GFP (b and d), or pFtsZ1(1–93)-GFP (e and f); (c) detail of a; (f) detail of e. a–c, and e and f, represent overlays of chlorophyll (red) and GFP (green) channel, in d only GFP channel is shown. Bars, 20 μm.
Mentions: Like their bacterial progenitors, both Physcomitrella proteins acted in a dose-dependent manner on the division process despite the presence of the COOH-terminal GFP fusion domain. Low FtsZ-GFP levels (indicated by weak GFP fluorescence) led to an enhancement of the division process and resulted in plastids that were significantly reduced in size (Fig. 3). In contrast, high FtsZ levels (indicated by strong GFP fluorescence) blocked plastid division (Fig. 4, a–d), leading to undivided, abnormally large plastids closely resembling the PpftsZ1-knockout phenotype (Strepp et al. 1998). The reduction of plastid size in cells overexpressing FtsZ-GFP indicates that the recombinant proteins are functional in division.

Bottom Line: It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton.Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure.As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term "plastoskeleton" for this newly described subcellular structure.

View Article: PubMed Central - PubMed

Affiliation: University of Freiburg, Plant Biotechnology, D-79104 Freiburg, Germany.

ABSTRACT
It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton. Recently, this belief was questioned by the finding that the bacterial cell division protein FtsZ resembles tubulin in sequence and structure and, thus, may be the progenitor of this major eukaryotic cytoskeletal element. Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure. Both their encoded proteins are imported into plastids and there, like in bacteria, they act on the division process in a dose-dependent manner. Whereas in bacteria FtsZ only transiently polymerizes to a ring-like structure, in chloroplasts we identified persistent, highly organized filamentous scaffolds that are most likely involved in the maintenance of plastid integrity and in plastid division. As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term "plastoskeleton" for this newly described subcellular structure.

Show MeSH
Related in: MedlinePlus