A look into nature ´s toolboxPathways of molecular evolution of cell division control discovered
14 October 2022, by Website Team Biologie
Photo: UHH/Schnittger
New insights into the molecular evolution of cell division control
An international research team led by the Department of Biology at Universität Hamburg has identified the elusive protein "Survivin" in plants, which has led to the discovery of relatives of this protein in many eukaryotes. "Survivin" has an essential function in anchoring chromosomes during cell division, but has so far only been found in fungi and animals. The results were published in the scientific journal "Proceedings of the National Academy of Sciences" (PNAS).
Proteins are the molecular machines of life. Among other things, they help to distribute the duplicated chromosomes to the newly developing daughter cells during cell division. One region on the chromosome in particular plays an important role in this process: the centromere. This is where various proteins come together, which, for example, link the chromosomes to the microtubule fibers of the spindle or control this linkage. The spindle then pulls the chromosomes to opposite cell poles so that two new cell nuclei and finally two cells can be formed. The so-called chromosomal passenger complex (CPC) plays an essential role in controlling the anchoring of the chromosomes to the spindle. If the CPC is defective or its function is impaired, severe developmental problems and diseases occur.
A central component of this complex is Survivin, which helps to attach the CPC to the centromere. So far, researchers have only identified this component in fungi and animals. Studies in the plant Arabidopsis thaliana, led by the developmental biologist Prof. Dr. Arp Schnittger from the Department of Biology at Universität Hamburg, have now led to the identification of two Survivin-like proteins - Borealin related interactor 1 and 2 (BORI1 and BORI2). Loss of these proteins is lethal, and reduced production of these proteins leads to severe developmental defects. The identification of Survivin-like proteins in plants then allowed related proteins to be found in almost all non-bacterial organisms.
The breakthrough was the discovery that “Survivin” in plants and many other organisms contains a structurally different, but functionally equivalent chromatin binding domain compared to animals while another, minor part of the animal and plant proteins evolved from the same progenitor. Interestingly, plants and other organisms seem to have "borrowed" the protein domain that is important for contact with the chromosome from bacteria. "Our studies are a nice example of the modularity of protein evolution," says Arp Schnittger. "Furthermore, our studies show how important it is to make use of nature's magnificent diversity, especially in molecular studies."
In the future, Schnittger now wants to work with colleagues at the University of Groningen in the Netherlands to study Survivin function in slime molds, which, interestingly, carry neither the plant nor the animal element for chromosome localization and thus probably are representative for the original equipment of the last common ancestor of plants and animals.
Original publication:
Komaki, S., Tromer, E.C., De Jaeger, G., De Winne, N., Heese, M. & Schnittger, A. (2022) Molecular convergence by differential domain acquisition is a hallmark of chromosomal passenger complex evolution. PNAS, 119 (42). https://doi.org/10.1073/pnas.2200108119