植物着丝粒含有大量的重复序列和反转座子，结构复杂并受表观遗传学调控。中科院遗传与发育生物学研究所韩方普实验室长期从事植物着丝粒的表观遗传学研究，曾在植物中首次发现着丝粒的失活现象并初步分析失活着丝粒的调控机制。

　　由于着丝粒的特殊表观遗传学调控机制，植物着丝粒的DNA序列暂不能直接用于植物人工染色体的构建。这也是植物人工染色体构建方法不同于人类等人工染色体的策略。为了更好地研究植物着丝粒的结构与功能，特别是着丝粒是如何形成的？该实验室利用玉米三号染色体特殊材料，发现来自玉米三号染色体的片段可以稳定遗传并没有检测到玉米着丝粒的重复序列（CentC和CRM）。但具有着丝粒功能分子标记如CENH3和CENPC以及组蛋白磷酸化的信号。CENH3-ChiP-Seq分析结果表明玉米3号染色体长臂上一段常染色质区域（区域大小为350kb）参与并形成了功能着丝粒，序列分析350kb区域含有22个基因，其中11个基因与CENH3紧密结合。

　　该研究结果于3月25日在PNAS在线发表（DOI:10.1073/pnas.1303944110），韩方普实验室博士后符书兰和工作人员吕振玲为本文的共同第一作者。本项工作同JamesBirchler和王秀杰实验室共同合作完成。

　　该研究得到科技部重大研究计划、国家自然科学基金委重点项目和中国科学院的资助。

论文摘要
　
　                                                                        

      De novo centromere formation on a chromosome fragment in maize

The centromere is the part of the chromosome that organizes the kinetochore, which mediates chromosome movement during mitosis and meiosis. A small fragment from chromosome 3, named Duplication 3a (Dp3a), was described from UV-irradiated materials by Stadler and Roman in the 1940s [Stadler LJ, Roman H (1948) Genetics 33(3):273–303]. The genetic behavior of Dp3a is reminiscent of a ring chromosome, but fluoresecent in situ hybridization detected telomeres at both ends, suggesting a linear structure. This small chromosome has no detectable canonical centromeric sequences, but contains a site with protein features of functional centromeres such as CENH3, the centromere specific H3 histone variant, and CENP-C, a foundational kinetochore protein, suggesting the de novo formation of a centromere on the chromatin fragment. To examine the sequences associated with CENH3, chromatin immunoprecipitation was carried out with anti-CENH3 antibodies using material from young seedlings with and without the Dp3a chromosome. A novel peak was detected from the ChIP-Sequencing reads of the Dp3a sample. The peak spanned 350 kb within the long arm of chromosome 3 covering 22 genes. Collectively, these results define the behavior and molecular features of de novo centromere formation in the Dp3a chromosome, which may shed light on the initiation of new centromere sites during evolution.

　　作者：ShulanFua,1,ZhenlingLva,1,ZhiGaob,1,HuajunWuc,JunlingPangc,BingZhanga,QianhuaDonga,XiangGuoa,Xiu-JieWangc,JamesA.Birchlerb,2,andFangpuHana,2

　　期刊名称：Proceedings of the National Academy of Sciences

　　期卷页：第卷第期~页

　　学科领域：生命科学?植物学?植物生理与生化

　　添加人是否为作者:否

　　原文链接：http://www.pnas.org/content/early/2013/03/20/1303944110

　　DOI：10.1073/pnas.1303944110

　　ISBN：0027-8424

　　关键词：

　　相关报道：http://paper.sciencenet.cn/htmlpaper/20134715524273028714.shtm

　　备注：