非细胞体系重建核染色质组装、结构和DNA复制

用lambda DNA和蛙卵提取物进行非细胞体系核重建实验,结果显示,lambda DNA参与构成了重建核的染色质;染色质组装是逐步进行的;组装的染色质含有典型的核小体串珠状一级结构、300的螺线管和染色质的更高级结构;重建核能够复制DNA。     

Chromatin and Nucleosome Organizations and DNA Replication of Nucleus Reassembled in vitro Using Purified Exogenous DNA and Xenopus Egg Extracts

It has been demonstrated in the last ten years that the nuclear reassembly may occur in the cell-free systems from frog egg extracts added with exogenous naked DNA. However, there remains an open question : is the cell-free reassembled nucleus structurally similar to the nucleus in the intact cell ? That is, does the cell-free reassembled nucleus contain nucleosomes and chromatin? For this issue, we have designed experiments for identifying the internal structures of the cell-free reassembled nucleus. These experiments show that the nucleus reassembled in vitro also contains chromatin which is composed of typical 10 nm nucleosome fibers of "beads-on-a-string", 30 nm filaments and the next higher-order structures. The digestion experiment with the enzyme micrococcal nuclease has demonstrated that the DNA in the nucleosome of the reconstituted chromatin is about 200 base pairs (bp) in length, of which 165 bp may be in the nucleosome particle, and 35 bp may be in the linker between two particles. Prolongin     

非细胞体系重建核生物学活性研究——重建核植入未受精卵能够诱导卵裂并进行细胞周期性变化

将HeLa细胞的中期染色体与成熟非洲爪蟾卵的提取物混合并加入ATP再生系统,经过一定时间的温育,可以自发进行非细胞体系(体外)细胞核构建。将体外重建核从核重建体系中分离出来,再移植到非洲爪蟾卵细胞中,能够诱导卵细胞进行卵裂。体外重建核本身可以随卵细胞进行细胞周期性变化。在卵细胞中有大量星体组装。