Centromere structures Centromere Kinetochore region microtubules Kinetochore Cellular pole Cellular pole Single microtubule Conserved AT Conserved element I rich element element l 5… ATAAGTCACATGAT三88b(93% AT) TGATTTCCG 3 TAT TCAGTGTACTA ACTAAAGGCTT 3 Yeast centromere sequence site of single microtubule attachment
Bacterial plasmid with yeast DNA sequence elements Yeast origin of replication Telomeres Yeast centromere Selectable marker Plasmid introduced into yeast cell Yeast cell Plasmid becomes linear Telomere Telomere
DNA Compaction (Chromosome Structure) and the Regulation of Gene Activity
DNA Compaction (Chromosome Structure) and the Regulation of Gene Activity
Gene compaction (a)DNA sensitivity to DNase (b)Locations of DH sites Gene at rest DNase I 1 o treatment Histone genes (Drosophila) H3 H4 H2A H2B DNA bound by DNA remains intact nucleosomes β globin genes (chick) Embryo Adult Nucle。 somes protect a-globin genes region from digestion (chick) Gene activation Light DNase I treatment 图, Gene to be Digested DNA Unwinding of nucleosomes transcribed at 5'end of gene Linker Gene transcription DNA Extensive Nascent transcripts DNase I treatment Ai-2 Nucleosomal RNA polymeras RNA polymerase displaces DNA throughout DNA nucleosomes as it transcribes the gene gene is digested