As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division...As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.展开更多
Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded b...Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded by a single gene, whereas plants harbor several nuclear-encoded FtsZ homologs. In seed plants, these proteins group in two families and all are exclusively imported into plastids. In contrast, the basal land plant Physcomitrella patens, a moss, encodes a third FtsZ family with one member. This protein is dually targeted to the plastids and to the cytosol. Here, we report on the targeted gene disruption of all ftsZ genes in R patens. Subsequent analysis of single and double knockout mutants revealed a complex interaction of the different FtsZ isoforms not only in plastid division, but also in chloroplast shaping, cell patterning, plant development, and gravity sensing. These results support the concept of a plastoskeleton and its functional integration into the cytoskeleton, at least in the moss R patens.展开更多
文摘As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.
文摘Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded by a single gene, whereas plants harbor several nuclear-encoded FtsZ homologs. In seed plants, these proteins group in two families and all are exclusively imported into plastids. In contrast, the basal land plant Physcomitrella patens, a moss, encodes a third FtsZ family with one member. This protein is dually targeted to the plastids and to the cytosol. Here, we report on the targeted gene disruption of all ftsZ genes in R patens. Subsequent analysis of single and double knockout mutants revealed a complex interaction of the different FtsZ isoforms not only in plastid division, but also in chloroplast shaping, cell patterning, plant development, and gravity sensing. These results support the concept of a plastoskeleton and its functional integration into the cytoskeleton, at least in the moss R patens.
