Multi-scale architecture of archaeal chromosomes.

Chromosome conformation capture (3C) technologies have identified topologically associating domains (TADs), and larger A/B compartments as two salient structural features of eukaryotic chromosomes. These structures are sculpted by the combined actions of transcription and structural maintenance of chromosomes (SMC) superfamily proteins. Bacterial chromosomes fold into TAD-like chromosomal interaction domains (CIDs) but do not display A/B compartment-type organization. We reveal that chromosomes of Sulfolobus archaea are organized into CID-like topological domains in addition to previously described larger A/B compartment-type structures. We uncover local rules governing the identity of the topological domains and their boundaries. We also identify long-range loop structures and provide evidence of a hub-like structure that colocalizes genes involved in ribosome biogenesis. In addition to providing high resolution descriptions of archaeal chromosome architectures, our data provide evidence for multiple modes of organization in prokaryotic chromosomes and yield insight into the evolution of eukaryotic chromosome conformation. Takemata and Bell reveal that chromosomes of archaea of the genus Sulfolobus organize into A and B compartments and, independently, into local domains akin to bacterial CIDs. Additionally, the genomes possess loop structures that can join loci separated by up to half the length of the circular chromosomes.

染色体构象捕获（3C）技术已经确定了拓扑相关结构域（TADs）以及更大的A/B区室，它们是真核染色体的两个显著结构特征。这些结构是由转录和染色体结构维持（SMC）超家族蛋白的联合作用塑造而成的。细菌染色体折叠成类似TAD的染色体相互作用结构域（CIDs），但不显示A/B区室类型的组织形式。我们发现，除了先前描述的更大的A/B区室类型结构外，硫化叶菌古菌的染色体还被组织成类似CID的拓扑结构域。我们揭示了控制拓扑结构域及其边界特性的局部规则。我们还确定了长程环结构，并提供了一种类似枢纽结构的证据，该结构使参与核糖体生物发生的基因共定位。除了提供对古菌染色体结构的高分辨率描述外，我们的数据为原核染色体的多种组织模式提供了证据，并深入了解了真核染色体构象的演化。 竹俣（Takemata）和贝尔（Bell）发现，硫化叶菌属古菌的染色体组织成A和B区室，并且独立地形成类似于细菌CIDs的局部结构域。此外，这些基因组具有环结构，能够连接被长达半个环状染色体长度分隔的基因座。