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

豆科植物根瘤中含有侵染细胞和未侵染细胞，在基因表达、倍性、代谢、形态等方面进行了区分。在这项工作中，我们专注于在感染细胞中只表达的豆血红蛋白（Lb）基因，通过比较感染细胞和非感染细胞之间Lb位点的状态，更好地了解高阶染色质结构水平上的基因调控。执行并澄清了下列事项：我们已经分离出两个Lb位点2的基因组克隆。我们已经建立了从结节中分离细胞核的方法。大多数Lb位点与核基质具有高亲和力。在一个Lb位点上发现了大量的碱基未配对区（BURs），这与观察到它含有许多mars相一致。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。发现Lb位点的甲基化水平相当低。无论表达如何，Lbc3基因周围对DNase I的敏感性相当高。因此，我们获得了有关Lb位点染色质结构的基本数据。有些发现不一定与先前报道的结果一致。基因表达与染色质结构之间的关系有待进一步研究。

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.