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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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In vivo filamentation of PpFtsZ1 and PpFtsZ2. FtsZ1-expressing cells (a and b) were analyzed by CLSM 2 d after transfection with FtsZ1-GFP plasmid. FtsZ2-expressing cells (c and d) were analyzed by CLSM 2 d after transfection with FtsZ2-GFP plasmid. An arrow points to the S-shaped structure, which may represent a plastid division ring. (e and f) Single section of the overlay shown in c and d visualizing the S-shaped structure in more detail. Bars, 5 μm.
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Figure 5: In vivo filamentation of PpFtsZ1 and PpFtsZ2. FtsZ1-expressing cells (a and b) were analyzed by CLSM 2 d after transfection with FtsZ1-GFP plasmid. FtsZ2-expressing cells (c and d) were analyzed by CLSM 2 d after transfection with FtsZ2-GFP plasmid. An arrow points to the S-shaped structure, which may represent a plastid division ring. (e and f) Single section of the overlay shown in c and d visualizing the S-shaped structure in more detail. Bars, 5 μm.

Mentions: In vivo localization by CLSM showed that both PpFtsZ-GFP fusions form organized, branched filamentous structures within Physcomitrella plastids (Fig. 5). This polymerization is due to the FtsZ part of the fusion protein, since the truncated pFtsZ(1–93)-GFP is distributed more diffusely within the organelle (see Fig. 2 i) compared with the complete FtsZ-GFP fusions (see Fig. 2, a and b). Both FtsZ scaffolds span the entire plastids and thus resemble the cytoskeleton in eukaryotic cytoplasm. We therefore suggest the term “plastoskeleton” to describe these structures. Additionally, these networks represent the first report to date on eukaryotic FtsZ filamentation in vivo. As FtsZ1-GFP and FtsZ2-GFP independently influence plastid division and even in low concentration are functional in division, we postulate that the scaffolds built by these fusion proteins mimic a naturally occurring state.


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)

In vivo filamentation of PpFtsZ1 and PpFtsZ2. FtsZ1-expressing cells (a and b) were analyzed by CLSM 2 d after transfection with FtsZ1-GFP plasmid. FtsZ2-expressing cells (c and d) were analyzed by CLSM 2 d after transfection with FtsZ2-GFP plasmid. An arrow points to the S-shaped structure, which may represent a plastid division ring. (e and f) Single section of the overlay shown in c and d visualizing the S-shaped structure in more detail. Bars, 5 μm.
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Related In: Results  -  Collection

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

Figure 5: In vivo filamentation of PpFtsZ1 and PpFtsZ2. FtsZ1-expressing cells (a and b) were analyzed by CLSM 2 d after transfection with FtsZ1-GFP plasmid. FtsZ2-expressing cells (c and d) were analyzed by CLSM 2 d after transfection with FtsZ2-GFP plasmid. An arrow points to the S-shaped structure, which may represent a plastid division ring. (e and f) Single section of the overlay shown in c and d visualizing the S-shaped structure in more detail. Bars, 5 μm.
Mentions: In vivo localization by CLSM showed that both PpFtsZ-GFP fusions form organized, branched filamentous structures within Physcomitrella plastids (Fig. 5). This polymerization is due to the FtsZ part of the fusion protein, since the truncated pFtsZ(1–93)-GFP is distributed more diffusely within the organelle (see Fig. 2 i) compared with the complete FtsZ-GFP fusions (see Fig. 2, a and b). Both FtsZ scaffolds span the entire plastids and thus resemble the cytoskeleton in eukaryotic cytoplasm. We therefore suggest the term “plastoskeleton” to describe these structures. Additionally, these networks represent the first report to date on eukaryotic FtsZ filamentation in vivo. As FtsZ1-GFP and FtsZ2-GFP independently influence plastid division and even in low concentration are functional in division, we postulate that the scaffolds built by these fusion proteins mimic a naturally occurring state.

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