Assembly and possible functions of heterochromatin in Arabidopsis thaliana - The role of DNA methylation and histone modifications

染色中心是间期核的异染色质区室。在拟南芥的细胞核中，它们可以被看作是一个单独的结构，每个结构都包含一个或多个着丝粒染色体区域。这种有序的模式极大地促进了间期染色体组织的研究。本项目主要研究植物细胞核中DNA序列、异染色质形成和基因表达之间的关系。基于荧光原位杂交技术对拟南芥间期核的研究，提出了间期染色体组织的一个模型，其中着丝粒区和其他异染色质片段位于染色中心，而常染色质片段则聚集在该中心周围形成染色质环。将对该模型进行测试。来自不同染色体区域的染色体和（异）着丝粒特异性DNA探针以及（异）染色质特异性抗体将用于分析间期不同阶段异染色质和常染色质的组成和组织。转基因和突变的拟南芥植物，这可能是在他们的染色质组织的影响，将与野生型进行比较。结合拟南芥的遗传和分子潜力，这种细胞学方法将为基因调控的表观遗传机制提供重要的见解。

Chromocentres are the hererochromatic compartments of the interphase nucleus. In Arabidopsis nuclei, they are visible as conspicious, individual structures, each containing one or more (peri)centromeric chromosome regions. This ordered pattern greatly facilitates the study of chromosome organization during interphase. This project focuses on the relationship between DNA sequence, heterochromatin formation and gene expression in plant nuclei. Based on FISH studies with interphase nuclei of Arabidopsis a model for the organization of a chromosome during interphase is proposed, in which the centromere region and other heterochromatic segments are located in the chromocentre, while the euchromatic segments are clustered as chromatin loops around this centre. This model will be tested. Chromosome- and (peri)centromere-specific DNA probes from distinct chromosomal regions, and (hetero)chromatin specific antibodies, will be used to analyse the composition and organization of heterochromatin and euchromatin in different stages of interphase. Transgenic and mutant Arabidopsis plants, which are likely affected in their chromatin organization, will be compared with the wild type. In conjunction with the genetic and molecular potential of Arabidopsis, this cytological approach will provide important isight into the epigenetic mechanism of gene regulation.