Research scientists Guohong Li (left) and Ping Zhu

30 nm chromatin fiber to four nucleosome structural unit

61 years ago, scientists Watson and Crick discovered the double helix structure of DNA, the genetic information uncover how to pass this 'mystery of life.' Chinese scientists announced on the 25th, they discovered the genome 'information carrier of life,' the second double-helix structure, namely the use of single-particle cryo-EM reconstruction of three-dimensional technology, the world's first 30 nanometer chromatin analytical high-resolution three-dimensional left-handed double helix advanced structures.

Researchers from the Institute of Biophysics team Zhu Ping, Li Ruiming Xu Guohong team and teamwork to complete the research paper published in the 25th edition of the American journal Science, reviewers evaluated as being 'troubled by the scientific community to solve a 30 years of the most fundamental questions in molecular biology ',' in understanding how chromatin assembly has taken an important step forward on this issue. '

We each individual has more than 200 different cells, these cells come from a single fertilized egg cell development, has the same genetic information, and why they are quite different morphological and physiological features of it

'The answer with 'life information carrier' of this problem - the dynamic structural changes and regulatory mechanisms of chromatin closely related.' Li Guohong said, but for decades, three-dimensional structure of chromatin is always a scientific community's 'black box' process development life on every cell of 'destiny' is how decisions and changes and disorders occur with the chromatin structure of human aging, cancer and other diseases have anything to do with issues such studies because of the lack of advanced fine chromatin structural information while experiencing varying degrees of distress.

According to reports, the body of a DNA 'string' length of about two meters, to be placed only a few microns in diameter nucleus, must somehow 'fold' Σ scientists have found that this process is completed in four steps , the corresponding four chromatin structure: The first stage is the nucleosome structure, the second level is the nucleosome structure to form the coil 30 nm chromatin fiber 30 nm chromatin further folded into a more complex staining High quality structure, i.e., supercoiled body is further folded over to form the spiral body can be seen under an optical microscope chromosome.

Previously, researchers have only resolved in 1997, the structure of the nucleosome precision, multiple nucleosome assembly of the manner in which the formation of advanced 30 nm chromatin structure there has been no answer. Guohong Li, Zhu equality after years of efforts, successfully established a set of chromatin structure in vitro reconstruction and analysis platform, using three-dimensional cryo-EM single particle reconstruction techniques to resolve the world's first 30 nanometer high-resolution three-dimensional chromatin structure.

'We found that 30 nm chromatin fiber to four nucleosome structural unit, each unit through mutual distortion between folded to form a left-handed double helix advanced structure, we have the first clear connection histone H1 in 30 nm chromatin important role in the process of fibrogenesis. 'Zhu Ping said.

Experts said the major scientific breakthroughs have significance for understanding aging and developmental differences over the development of the individual, such as cancer, diabetes, mental illness and neurological disorders and other complex diseases, and so plays a key role, will explore treatment of major diseases and drug development provide important theoretical guidance.

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