两种模式生物核小体定位比较研究

A comparative study of nucleosome positioning pattern in two model organisms

在对两种模式生物酵母与果蝇胚胎期核小体定位进行研究时,发现不同物种间以及同一物种中不同表达模式基因上的核小体分布呈现出差显著异性。在总体上,转录起始位点附近的酵母核小体NFR区域比果蝇的NFR短。经基因中心对齐后,酵母与果蝇胚胎期沉默型基因的核小体缺失区域的两个边界中间处共同呈现了一个明确有着均匀间隔的核小体数n,且随着基因长度L的变长其周期性特性逐渐变模糊,但果蝇的图谱表现的更为复杂。结果表明,从单细胞酵母生物到多细胞果蝇生物间基因组的进化过程中,核小体组织的演化既有变异性,也具有保守性。

By studying nucleosome positioning during embryonic period of two model organisms, Yeast and Drosophila, we found that nucleosome are differently distributed along genome-wide genes which either belong to different species or the same species in different expression patterns. In general, nucleosome free regions （ NFR） regions around the transcription start sites in yeast are narrower than that in Drosophila. If aligned by the gene center, there always are a well-defined number n of uniformly spaced nucleosomes in the middle of NFRs for embryo silence genes in both species, and the characteristics of these uniformly spaced nucleosomes gradually go fuzzy with the gene length L being longer , while drosophila presents more complexity and ambiguity than yeast relatively. The results show that the evolution of genome nucleosomes organization holds both variability and conservatism from unicellular organism to the multicellular organism.