Scientists have found meiosis exit Arabidopsis controlled by P-body-mediated inhibition of translation
Albert Cairo, Karel Riha and their colleagues have discovered a previously unknown mechanism for reprogramming gene expression during the transition when one cell differentiates into another. The mechanism occurs at the end of meiosis, a specialized cell division required for sexual reproduction, allowing the differentiation of germ cells and pollen.
This mechanism involves the dynamic localization of key regulatory components into intracellular condensates that resemble liquid droplets. This process is directly related to seed production and may offer new opportunities to create more sustainable crops that can withstand harsher environmental conditions. The findings were recently published in a prestigious journal Science.
Cells are not static things; they change from one type to another. Activation of a particular collection of genes affects how cells specialize in performing specific tasks and when they divide or differentiate. Cell biologists such as Albert Cairo and Karel Riha use a combination of sophisticated scientific methods to study the microworld of the plant. Cell biology is currently undergoing a revolution, the traditional perspective of cell organization is expanding to new horizons.
“We now know that the cell not only contains the traditional membrane-delineated organelles, but that many molecular processes are confined within less defined membrane-less organelles called biomolecular condensates (biocondensates). Over the past decade, the importance of these biocondensates has begun to be recognized. Now we we contribute to this field by showing how a specific type of biocondensate is formed at the end of meiosis and inhibits protein synthesis,” explains Albert Cairo, the first author of this study.
“This, on the one hand, stops the meiotic processes, but on the other hand, it indicates the beginning of the generation of genetically different cells,” adds Cairo. But that’s not all. The research team believes that similar mechanisms are at work in other organisms and cellular structures, including cell differentiation or stress responses.
The discovery of the members of Karel Riha’s laboratory could have a major societal impact.
“We are living in a climate emergency. Although plants can cope with various stresses, including high temperatures and drought, their development and reproduction can be severely impaired. This means that we face the risk of a sharp decline in productivity when productivity needs to be increased to meet human demand. And that’s why plant research should now be one of the priorities,” explains Karel Riha, author and head of the research group.
The main mission of the laboratory is to elucidate the fundamental biological processes closely related to plant reproduction and seed formation, which in many plants translates into fertility.
“Research results show that biomolecular condensates play an important role in plant productivity, and their behavior is likely linked to environmental stress. It is therefore clear that our discovery is the first step in the development of new solutions that result in sustainable product production in harsher conditions,” explains Albert Cairo.
The technical approaches taken by the team are truly commendable and the publication of this study Science He is confident that Rihan’s lab is headed in the right direction.
The road to discovery
Study of meiosis in a model plant Arabidopsis thaliana especially difficult. The research team focused on unusual and rare cells hidden in tiny flower buds measuring 0.1-0.4 mm. Moreover, the meiotic division steps that are the focus of the study happen quickly—the entire process takes five to six hours. Therefore, it is not easy to catch them. The research team must use state-of-the-art technologies and a significant amount of creativity and imagination to explore this process.
Rihan’s team had to create conditions for live imaging of meiotic division inside the anther (the part of the stamen that contains the pollen). The team used advanced microscopy and became one of only two laboratories in the world to observe plant meiosis live. Another important experience gained by the team was the adoption of protoplast technology. Protoplasts are isolated plant cells that lack a surrounding cell wall, making them easier to manipulate genetically and visualize under a microscope. This technology allowed the team to clarify some problems more quickly and efficiently than using meiotic cells.
Anna Vargova made a significant contribution to the understanding of the newly described complex mechanism. Pavlina Mikulkova showed her expertise and magic hand with the lens as she performed live cell imaging of meiosis using a Lightsheet microscope. The research team was supported by CEITEC’s core facility CELLIM and the Plant Sciences Core Facility. The research took more than eight years and was funded by the Youth and Sports grant project REMAP of the Czech Ministry of Education. “Without the long-term funding we have, it would be extremely difficult to develop such a complex project. In fact, at one point it seemed to us that our limit was only our imagination, and I believe that this was very important for our large-scale discovery,” says Albert Cairo.
Reference: “Meiotic exit Arabidopsis Albert Cairo, Anna Vargova, Neha Shukla, Claudio Capitao, Pavlina Mikulkova, Sona Valuchova, Jana Pecinkova, Petra Bulankova and Karel Riha, 4 August 2022. Science.
Interestingly, this project does not involve any external collaboration, which is unusual for international research institutes like CEITEC. In this case, the research group took a completely new direction and the study was completed only by members of Karel Rihan’s research group.
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