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The pressure of life, environmental stimuli, accidents … Globally, several factors have caused an increase in the rate of infertility, and many couples who originally wanted to have children are even more concerned about this.
But the latest study may become your new hope. Scientists say that identifying the transcription factors that cause oocyte growth will aid reproductive biology research and may help women solve fertility problems.
A few days ago, a study marked the beginning of a breakthrough: a core group of eight proteins can transform pluripotent mouse stem cells in the laboratory into cells that look like immature eggs, called oocytes. Cells (oocytes).
The researchers reported in the journal Nature on December 16, local time, that oval cells cannot undergo meiosis and cannot divide the total number of chromosomes in half, but can be fertilized by sperm and then divide into the embryo. 8 cellular stages of development.
“This shows that it can be transformed directly from stem cells into oocytes. I think this is exciting,” said Petra Hajkova, developmental epigenetist at Imperial College London, who was not involved in the study. He noted that this work will help researchers explore the basic developmental biology of oocytes. Study co-author Hamazaki Nobuhiko of Kyushu University in Japan said that in the future, this study could help clone endangered animals or help women with mitochondrial diseases to have healthy children.
Hamazaki said oocytes are a rare cell type in the human body, and little is known about them, prompting him and his colleagues to explore how they develop.
Previous studies have shown and documented how changes in gene expression have a critical impact on the transition from early germ cells (primordial germ cells) to oocytes. On this basis, Hamazaki and his colleagues conducted a gene expression analysis and identified 27 candidate transcription factors (ESCs) that play a role in the genetic transformation process.
To test the function of each transcription factor, the research team used pluripotent embryonic stem cells (ESCs) to knock out or inactivate genes that encode transcription factors one by one.
Hamazaki said: “It is relatively easy to do knockout ESCs than to knockout mice, although it is still hard work to do 27 knockout ESCs.”
The experiment found 8 transcription factors that are essential for the development of oocytes: NOBOX, FIGLA, TBPL2, SOHLH1, STAT3, DYNLL1, SUB1 and LHX8. The research team then grew another group of embryonic stem cells and overexpressed the genes that produce these transcription factors, allowing these cells to enter an egg-like state.
“People think that oocytes develop from germ cells, but we can generate oocytes from non-germ cells,” he explained. “At first, I was surprised. I couldn’t believe my results, so I repeated the experiment over and over again. When I got the same results, I was finally convinced.”
In later experiments, the oval cells did not continue to divide into daughter cells with half a set of chromosomes, which would allow them to reproduce. But the researchers wrote that when the team introduced wild-type mouse sperm into the culture medium, the oocytes divided into 8 cells before losing viability, probably because these cells had too many chromosomes.
Richard Schultz, a cell biologist at the University of California, Davis, who was not involved in the study, said the work to identify a basic set of transcription factors is impressive. These transcription factors can cause embryonic stem cells to enter a state. that looks like an oocyte.
But oval cells don’t undergo meiosis, so they don’t work. In other words, further development beyond this stage will be affected. “This is a huge improvement, but only 95% were successful. We don’t have 100% results” to understand the necessary factors behind the increased maturation and evolution of germline eggs into oocytes, and the next half of those chromosomes that develop into living eggs. .
Although no pathway to meiosis has been found, this work “allows us to produce a large number of oocytes.” We believe this technology can accelerate basic biological research on oocytes, which remain one of the most mysterious cell types. Hamazaki said.
Oocytes are very unique because they have the ability to produce more than 200 highly differentiated cells needed to create an individual, and the key to this ability is to fill the complex mix of substances in the liquid cytoplasm within the cell.
Oocytes and their cytoplasm are so unusual that the replacement of the nucleus of the oocyte containing DNA by the nucleus of the somatic cell allows a new life to be “created”.
He explained that this work can improve animal cloning because the team’s technology produces a large number of oocytes. The plasma of the induced oocytes did not show abnormalities, so it can also be used in reproductive techniques for women with mitochondrial diseases.
Children inherit the disease from their mothers, but after using oocytes derived from enucleated stem cells, they can have healthy mitochondria that serve as nuclear carriers for the infected mother’s oocytes. He noted that this may be a solution to solve this problem. “This is a long-term view, but it shows how these oocytes can be helpful.”
Nowadays, scientists around the world have come a long way in treating infertility: in addition to artificial oocytes this time, there are also artificial sperm and parthenogenesis / parthenogenesis in mammals. It is no longer out of reach.
Compilation / Foresight Economist APP Information Group
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