中文摘要：

真核细胞中，基因组DNA缠绕组蛋白八聚体形成核小体，核小体再经过多层次折叠压缩形成具有高级结构的染色质．过去30多年，科学家对30nm染色质纤维的结构进行了大量的研究，然而关于30nm染色质纤维的精细结构仍然存在很大的争议．本文综述了近年来对30rim染色质纤维结构的最新研究进展，并重点阐述了最近解析的30nm染色质纤维左手双螺旋结构．同时，我们还进一步讨论了一些对30nm染色质纤维结构起调控作用的因子及其作用机制．最后，我们对30nm染色质纤维结构与功能领域所面临的挑战和问题进行了展望．

英文摘要：

In eukaryotic cells, genomic DNA is hierarchically packed into chromatin by histories in the nucleus. Despite of over 30 years＇ study, the fundamental structure of 30 nm chromatin fiber remains controversial. In this review, we focus on recent progress in revealing the structure of 30 nm chromatin fiber, and emphasize on the most recent left-handed double helix structure of 30 nm chromatin fiber. In addition, we discuss the epigenetic regulation of the 30 nm chrornatin structure. Finally, we discuss the possible challenge in elucidating the structure of 30 nm chromatin fiber and its regulation.