(2)包装模型 Nonhistone 100A scall protens 300A Nonscalld Loop chroman 100A nber elephas Metaphase chromosome chromatin vel packaging. (a) Electron micrographs contrasting the 100-A fiber deft) with the 300A fiber (right. The H号h t d ruckosomes (with green cores) in these structur h61h认 satir ba%ral bops togther into daisy ike rosettes and then compress the rosette centers into a compact bundle. by nonhistone scaffok protein bron and crange) inluding topoisomerase ll (brown). (c)Additional nonhistone protens might
(2)包装模型
(3)染色体DNA的关键序列 origin centromere telomere Eukaryotic chromosomes have multiple origins of replication. (a)Electron micrograph and diagrammatic interpretation, showing a region of replicating DNA from a Drosophila embryo. Many origins of replication are active at the same time, creating multiple replicons. (b) Structure of the yeast origin of replication ARSI. The orange- boxed sequence is the AT-rich consensus region found in all arS elements. The blue boxes are the flanking sequences close to the ARSI consensus region that promote function Consensus regio . CAAATTTCGTCAAAAATGCTAAGAAATAGGTTAT TACTTTTATTTAAGTATTGTTTGTGCCTTTTGAAAAGCAAG CATAAAAGATCTAAACATAAAATCTGTAAAATAAC-3 GTTTAAAGCAGTTTTTACGATTCTTTATCCAATAATGAAAATAAATTCATAAC AAACACGGAAAACTTTTC GT TC GTATTTTCTAGATTTGTATTTTAGACATTTTAT TG*e5
(3)染色体DNA的关键序列 origin centromere telomere