Analysis of gene regulation at the level of higher-order chromatin structure in the soybean leghemoglobin gene locus

豆科植物的根瘤含有感染细胞和非感染细胞，它们在基因表达、倍性、代谢、形态等方面存在差异。在这项工作中，我们聚焦于在感染细胞中唯一表达的豆状血红蛋白(Lb)基因，通过比较感染细胞和未感染细胞Lb基因的状态，在高阶染色质结构水平上更好地了解基因调控。1.我们分离了覆盖两个Lb基因座的基因组克隆。2.我们建立了从根瘤中分离细胞核的方法。3.大多数Lb基因座与核基质具有很高的亲和力。4.在一个Lb基因座上发现了大量的BUR(碱基分离区域)，5.我们建立了从感染细胞和未感染细胞中分离原生质体的方法。6.发现Lb基因的甲基化水平较低。7.无论Lbc3基因的表达如何，对DNase I的敏感性都很高。因此，我们获得了关于Lb基因染色质结构的基础数据。一些发现不一定与之前报道的结果一致。为了阐明基因表达与染色质结构之间的关系，还需要进一步的研究。

Nodules of leguminous plants contain infected and non-infected cells, which are discriminated in gene expression, ploidy, metabolism, morphology and so on. In this work, we focussed on leghemoglobin(Lb)genes which are expressed exclusively in infected cells, to lead a better understanding of gene regulation at the level of higher-order chromatin structure by comparing the state of the Lb locus between infected and non-infected cells. Followings were carried out and clarified.1.We have isolated genomic clones covering two Lb loci.2.We have established the method of the isolation of nuclei from nodules.3.Most of the Lb loci have high affinity with the nuclear matrix.4.A large number of BURs(base-unparing regions)were found in an Lb locus, consistent with the observation that it contained many MARs.5.We have established the method by which protoplasts were isolated from infected and non-infected cells separately.6.Methylation levels in the Lb loci was found to be rather low.7.Sensitivity to DNase I is rather high around the Lbc3 gene irrespective of expression.Thus, we have obtained basic data concerning the chromatin structure of the Lb loci. Some findings are not necessarily consistent with previously reported results. Further investigation is necessary to clarify the relationship between gene expression and chromatin structure.