How cells divide and create new lives is a mystery that has long been fascinated by scientists. At the center of this process is a structure called the spindle, which is essential for classification and transferring chromosomes into new cells. Think of it as a cellular machine that ensures that each new cell receives the correct set of genetic instructions. The machine runs through linear structures called microtubules, which come in two types, each with a unique role in moving and locating chromosomes. At the heart of this operation is kinetics, connecting chromosomes to complex protein structures on these microtubules. Especially in meiosis, a unique form of cell division is essential for sexual reproduction, and understanding the interactions of these components is crucial. Meiosis involves two rounds of chromosome classification after a single DNA replication, resulting in the formation of haploid gametes or sex cells. This study delves into the mechanisms of how these components work together during the transition from the first round of meiosis, a process that is fundamental to cell biology, but is not fully understood.
In the discovery of Professor Juan Jimenez and his team Sergio Villa-Consuegra and Professor Tarada, Professor Víctor Tallada from the University of Pablo de Olavide, a protein called Aurora B kinase in MEIOSIS The key role has been revealed. This protein plays a central role in meiosis, which is crucial for sexual reproduction. Their research, published in the journal Iscience, uses fission yeast as a model organism and provides profound insights into the complexity of meiosis.
Professor Jimenez explained: “In meiosis, to ensure the accurate distribution of genetic material, it is crucial that certain structures within the cell (called spindle microtubules – metal block arrays) act in a specific way. . In the first round of meiosis (MI), they need to align homologous chromosomes, but in the second round (MII), they need to separate sister chromatin agents. “This distinction is for accurate genetic distribution To the resulting gametes are crucial.
The focus of the study is Aurora B kinase, a key protein previously known for standard cell division or mitosis. “We found that relocalizing this protein to different parts of the cell is critical to resetting these structures from the first round, satisfying the so-called spindle assembly checkpoint (SAC) and generating the appropriate arrangement for the appropriate arrangement. The second round of splits,” Professor Jimenez said. This relocalization is critical to prevent errors in chromosome distribution during meiosis II, which can lead to birth defects and infertility in humans.
The team uses various exquisite techniques to reveal the key role of Aurora B kinase in meiosis. They used specific inhibitors in the Aurora B kinase inhibition assay to understand the functional role of the protein during meiosis. In addition, live cell microscopy allows researchers to observe and record dynamic processes that occur in living cells in real time. This is particularly important for studying the behavior and interaction of chromosomes and spindle fibers during cell division. Finally, the team conducted detailed image analysis and measurements of spindle and chromosome dynamics. This involves capturing and analyzing high-resolution images to quantify changes in spindle structure and chromosomal movement, resulting in a comprehensive understanding of the meiotic process at the molecular level.
The study further reveals the key functions of a protein called IMP1 in this process. “In cells lacking sufficient amounts of this protein, we observed that structures assemble structures from the first and second rounds simultaneously, resulting in cells coexisting both structures. This unusual situation leads to a reduction in the second round Errors in the division of numbers highlight the importance of timely dynamics of these cellular structures.”
Professor Jimenez elaborated on the accuracy required during these cellular processes, “The delay caused by the cyst allows the cells to have enough time to correct any improper attachment, ensuring accurate chromosome distribution during standard cell division.”
One of the most important findings of this study is the role of complexes involving Aurora B in restoring normal chromosomal distribution. “The release of the complex from a specific region in the cell during the transition between two rounds of meiosis is a critical step. It allows the cell to reset the dynamically arranged for the correct structure to assemble at the beginning of the second round. , for chromosome distribution and proper SAC function,” explained Professor Jimenez. This finding highlights the complex interactions of cellular components during meiosis.
In summary, this study not only enriches our understanding of meiosis, but also provides new avenues to address genetic diseases caused by meiosis errors.
Journal Reference
Sergio Villa-Consuegra, Víctor A. Tallada, Juan Jimenez, “Aurora B kinase erases monopolar microtubule array arrays during meiotic I-II transition,” ISCIENCE, 2023, 2023. ISCI.2023.108339.
About the Author
Dr. Juan Jimenez He is a full professor of genetics at the University of Pablo De Olavide (UPO) and PI at the CABD Institute in Seville, Spain. He received his PhD in Genetics from the University of Seville, Spain in 1987 and conducted a period of research at the College of Sciences, Goul, supervised by Professor N. van Uden. During this time, he was an assistant professor in the Department of Genetics, received a UNESCO scholarship and a Sevilla City Council Award. In 1987, he began his postdoctoral period at ICRF in London and started the Dr. Paul Nurse Laboratory (2001 Nobel Prize) at the Microbiology Department of Oxford University, UK, with Dr. David Glover (University of Dundee, UK ) Work closely together) ) Identify the main genes that regulate the cell cycle during fly development. He received a cephalosporin junior research scholarship at Linacre College. In 1989, he returned to the Spanish professor at the School of Science at the University of Malaga. In 2000, he moved to UPO, where he was vice president of research and president of the university. During his time as Vice President, he co-founded the CABD Institute (UPO Research Center) and was the first director of the center. In 2012, he was a research visitor to the Department of Biochemistry at the University of Cambridge, UK (Juan Mata’s Laboratory). His research focuses on how different cellular functions, such as translation, cytokines or spindle disassembly coordinate with mechanisms that regulate mitotic and meiotic cell cycles. Application research on biofilm formation through the development of “Flor Wine Yeast” and algorithms for finding small ORFs (Anablast) in computers is also the research topic of its group (OrcID: -0002-3851-7393).
