Chinese scientists have revealed the structural dynamics of chromosomes in early human embryos

2 a.m. Beijing time on December 5, nature magazine published the results of a team study by
Liu Jiang, a researcher at the Beijing Genomics Research Institute, and Chen Zijiang, a professor at
And Shandong University's affiliated Reproductive Hospital.
This study reveals for the first time the dynamic changes of chromosome 3D structure in early human embryos, and finds that CTCF protein has important regulatory functions for the topologically related domain (TAD structure) in early embryonic development, which provides a theoretical basis for further revealing the mechanism of human embryo development.
three-dimensional structure of chromosomes is an important prescial genetic factor, which is closely related to gene expression regulation.
changes in the three-dimensional structure of chromosomes affect the function of cells and the occurrence of diseases.
human individual development begins with the binding of sperm eggs to form fertilized eggs, goes through the early embryonic development process, and gradually divides and differentiates from one cell to form a complex organism containing hundreds of cell types and multiple organs.
"How chromosome structures change in the nucleus of cells and which biological molecules affect changes in chromosome structures in embryos has long been an unresolved scientific question."
addition, sperm is very different in form and function from other cells that eventually differentiate, and it is not clear how chromosomes compress and fold in human sperm. Chen Xuepeng, the paper's first author and
research assistant at the Beijing Genomics Research Institute in Beijing, China, said.
structure of the genome chromosome consists of the basic units of topologically related domains (TADs).
researchers have described dynamic changes in chromosomal structure in sperm and early human embryonic development.
study showed that there was no TAD structure in mature human sperm and no chromatin-regulating protein CTCF was detected, unlike in mouse sperm.
fertilization, the TAD structure in the embryo is very blurred, and the chromosomes gradually establish a clear TAD structure in subsequent embryonic development.
Chen Xuepeng points out that, unlike mouse embryos and fruit fly embryos, blocking ZGA in early human embryos inhibits the establishment of TAD structures.
further studies have found that the expression of CTCF proteins is very limited before the hemoglobin is activated, and the amount of expression increases rapidly during the activation of the hemoglobin during the emergence of the TAD structure.
knocking low CTCF proteins in embryos can lead to significant weakening of THED structure, suggesting that the expression of CTCF proteins when the hemologic genome is activated is critical to the establishment of TAD structures in early human embryos.
study gives us insight into the uniqueness of the chromosome structure of human sperm and early embryos, providing a theoretical basis for improving IVF techniques and promoting eugenics. Liu Jiang said.
, he points out that the current bottleneck in this area is that chromosome structures have lower resolution with a small number of cells.
" next step, we will continue to optimize methods, improve resolution, and strive to solve clinical problems through our research for the benefit of mankind. For
paper information: