During mitosis, the nuclear lamina in higher eukaryotic cells undergoes a distinctly morphological change.It breaks down into lamin polymers or monomers at prophase. At telophase, the lamins reassemble around the cond...During mitosis, the nuclear lamina in higher eukaryotic cells undergoes a distinctly morphological change.It breaks down into lamin polymers or monomers at prophase. At telophase, the lamins reassemble around the condensed chromatin to form the layer of lamina. Using antiserum to mammalian lamins, we studied the dynamics of lamina during cell division in the macronuleus of Tetrahymena shanghaiensis, which divided in the way of amitosis. In contrast to those in higher animal cells, the typical perinuclear lamin distribution in the macronucleus persisted throughout the whole cell cycle. It was further found that in some synchronized cells, the lamin distribution displayed an unusual pattern consisting of a series of spots within the macronucleus. Using South-western hybridization, we found that the purified 66 KD lamin in Tetrahymena showed specific affinity with the telomere DNA sequence in the same species. Therefore, we propose that pattern of immunofluorescence may be due to the interaction of lamin protein with the nucleoli and the condensed chromatins in the macronucleus.展开更多
A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the rea...A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.展开更多
文摘During mitosis, the nuclear lamina in higher eukaryotic cells undergoes a distinctly morphological change.It breaks down into lamin polymers or monomers at prophase. At telophase, the lamins reassemble around the condensed chromatin to form the layer of lamina. Using antiserum to mammalian lamins, we studied the dynamics of lamina during cell division in the macronuleus of Tetrahymena shanghaiensis, which divided in the way of amitosis. In contrast to those in higher animal cells, the typical perinuclear lamin distribution in the macronucleus persisted throughout the whole cell cycle. It was further found that in some synchronized cells, the lamin distribution displayed an unusual pattern consisting of a series of spots within the macronucleus. Using South-western hybridization, we found that the purified 66 KD lamin in Tetrahymena showed specific affinity with the telomere DNA sequence in the same species. Therefore, we propose that pattern of immunofluorescence may be due to the interaction of lamin protein with the nucleoli and the condensed chromatins in the macronucleus.
文摘A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.
