Release date: 2018-01-17
Telomeres are small segments of DNA-protein complexes present at the ends of eukaryotic cells that have an irreplaceable role in maintaining chromosome integrity and controlling cell division cycles. Telomere length reflects the history of cell replication and replication potential and is known as the "mitotic clock" of cell life. Telomeres play an important role in the process of meiosis, and there is a special phase in the early stage of meiosis - the flowering stage. At this time, telomeres accumulate in specific regions of the nucleus, forming a bouquet-like structure, which plays an important role in the repair of programmed DSB, the association of homologous chromosomes, and the occurrence of homologous recombination. The telomeres in the bouquet period are close to each other, forming an abnormally crowded microenvironment, which leads to adhesion. However, studies on the protective mechanism of telomere ends during meiosis have not been reported.
Recently, the Li Wei research group of the Institute of Zoology of the Chinese Academy of Sciences used the TRF1 knockout mouse model to find that TRF1 is one of the components of the telomere protective protein and is directly involved in the anchorage of the telomere to the nuclear membrane and the telomere integrity. During the protection process, it plays an important role in the process of spermatogenesis. Studies have shown that knockdown of Trf1 results in infertility in male mice, reduced testicles and almost no mature sperm production, which is highly similar to clinical azoospermia. Histological examination revealed that a large number of germ cells were lost in the testis of Trf1 knockout mice, and apoptotic cells were significantly increased. Mechanism studies have found that the deletion of TRF1 disrupts the anchorage of telomere ends and nuclear membrane, which seriously affects the repair of programmed DSB, homologous chromosome pairing, association and homologous recombination, resulting in a large number of meiotic cell arrest. In the thick line of meiosis, the loss of TRF1 causes adhesion at the end of telomere, abnormal chromosome separation, and meiosis is further arrested in the middle of meiosis, eventually leading to massive apoptosis of germ cells. This study revealed that telomere-associated proteins play a two-fold role in meiosis. One is to mediate the anchorage of telomeres to the inner membrane, and the other is to play a role in telomere end-protection to prevent chromosome terminal adhesion. Further research found that TRF1, Speedy A and CDK2 can participate in both processes simultaneously. TRF1 binds to CDK2 indirectly through the scaffold protein of Speedy A, which directly anchors telomeres to the inner membrane, promotes normal meiosis, and plays a role in telomere end protection, thus revealing the flowering stage during meiosis. A unique new mechanism for telomere protection in this particular phase.
The study was completed by the Institute of Animals, the University of Gothenburg, Sweden, and the Reproductive Medicine Center of Shandong University. On January 8, the relevant research results were published on Cell Death and differentiation. The research work was funded by the Ministry of Science and Technology's “National Key R&D Program†and the National Natural Science Foundation.
Source: Animal Institute
Reflective Sheeting,3M Reflective Sheeting,Best Reflective Tape,Colored Reflective Tape
Kunshan Jieyudeng Intelligent Technology Co., Ltd. , https://www.yuhuanptapes.com