Study and observe the B-Z conformational transition of DNA in chromatin remodeling

  In recent years, research on Z-DNA (Z-DNA) has attracted attention, but there are still difficulties in observing it in cells. The main reason is the lack of a simple and reliable method to directly observe it. Recently, researcher Huang Qing's research group at the Institute of Intelligent Machinery, Hefei Institute of Material Science, Chinese Academy of Sciences and Zhang Fengqiu's research group at Zhengzhou University have used infrared spectroscopy to observe and study the BZ conformational transition of DNA in chromatin remodeling. Related research results were published in Analytical On Chemistry.

  Chromatin remodeling is one of the main research contents of epigenetics, generally including histone covalent modification type or ATP (a high-energy phosphoric acid compound) dependent type. Covalently modified histones change the looseness or condensation state of chromatin by affecting the affinity between histones and DNA double strands; ATP-dependent chromatin remodeling changes the relationship between histones and DNA through chromatin remodeling complexes. The binding state establishes a special conformation on the surface of the DNA close to the core histones, thereby making the process of transcription factors more accessible to the DNA. In the process of chromatin remodeling, the interaction between histones and DNA will change, which may lead to changes in DNA conformation. Among them, the Z-DNA conformation may be more conducive to destroying the structure of the nucleosome, maintaining a more open chromosomal structure at the promoter, thereby promoting transcription.

  In order to investigate the DNA conformational changes caused by chromosome remodeling in cells, the researchers used infrared spectroscopy to observe and analyze the characteristic peaks related to DNA in the cell spectrum, and found that by regulating the catalytic subunits in the chromatin remodeling complex SWI/SNF Based on BRG1/BRM, it can induce chromatin remodeling, and thus induce the BZ conformational transition of DNA. Infrared spectroscopy has the characteristics of simple, rapid, and non-destructive detection, and can perform qualitative and quantitative analysis of biological macromolecules in cells. Previously, Huang Qing’s group used infrared spectroscopy to characterize Z-DNA and found that histone acetylation can cause Z-DNA transition in chromatin (Analytical Chemistry, 2015, 87: 2511-2517); in this study, the researchers used Infrared spectroscopy technology, exploring the DNA conformational transition in ATP-dependent chromatin remodeling, and using chromatin immunoprecipitation technology to further verify the Z-DNA conformational transition in chromatin remodeling, which proves that infrared spectroscopy characterizes Z-DNA Reliability of results.