SPINDLE ASSEMBLY CHECK POINT I CELL CYCLE скачать в хорошем качестве

SPINDLE ASSEMBLY CHECK POINT I CELL CYCLE

Spindle assembly check point present between metaphase to Anaphase transition state. detail description present in the video. The spindle assembly checkpoint (SAC), also known as the mitotic checkpoint, is a crucial mechanism that ensures accurate chromosome segregation during cell division. It operates during the metaphase stage of mitosis or meiosis, specifically monitoring the attachment of chromosomes to the spindle apparatus. During cell division, replicated chromosomes must be accurately distributed to each daughter cell to maintain genomic integrity. The spindle apparatus, composed of microtubules and associated proteins, plays a key role in this process by physically moving and segregating chromosomes. The spindle assembly checkpoint detects any abnormalities or errors in chromosome attachment to the spindle fibers. If chromosomes are not properly aligned or attached to the spindle, the checkpoint inhibits the progression of the cell cycle into anaphase, where chromosomes would otherwise segregate. This delay allows time for error correction mechanisms to fix any attachment errors. Key components of the spindle assembly checkpoint include proteins such as Mad1, Mad2, Bub1, BubR1, and Bub3, which are localized at kinetochores (protein structures on chromosomes where spindle fibers attach). These proteins monitor the tension and attachment status of chromosomes at the kinetochores. Once all chromosomes are properly attached and tension is exerted on them, the checkpoint is satisfied, and anaphase proceeds, leading to the separation of sister chromatids and their equal distribution to daughter cells. Failure of the spindle assembly checkpoint can lead to aneuploidy, a condition characterized by an abnormal number of chromosomes in daughter cells, which is associated with various diseases, including cancer. Therefore, the spindle assembly checkpoint is crucial for maintaining genomic stability and preventing the development of abnormal cells.