The Oliferenko Group
Group Leader: Dr Snezhana Oliferenko
Cellular dynamics of growth and division
We study how cells establish polarized states and navigate the mitotic division. These processes require a defined intracellular organization that is robust across a variety of environmental conditions. Yet, it shows a remarkable plasticity as cells progress through the cell cycle and respond to the extracellular cues. This balance between order and plasticity is at heart of cellular physiology. Its disruption has severe physiological consequences and could lead to developmental defects and disease.
We focus on how the endomembrane system functions together with the cytoskeletal polymers in defining the cellular organization. The essential feature of eukaryotic cells is the presence of internal membranes and in particular, the membrane-bound nucleus. The outer membrane of the nuclear envelope is continuous with the endoplasmic reticulum and therefore the dynamics of these organelles are tightly linked. Nuclear and ER geometry change as cells grow, divide and interact with their environment. During mitosis cells remodel their nuclear membranes to accommodate the mitotic spindle assembly, chromosome segregation and formation of the daughter nuclei. Understanding how nuclear organization is controlled during cellular growth and proliferation is of major biological and medical interest. We study how the nuclei grow and remodel, how the nuclear envelope dynamics is entrained into the cell cycle and how different strategies of mitotic nuclear envelope management arise in evolution.
We use two related species of fission yeast with markedly different mitotic programs, Schizosaccharomyces pombe and Schizosaccharomyces japonicus, as the sister model organisms. We integrate yeast genetics, genomics, biochemistry and experimental biophysics together with high-end live cell imaging and image analyses. Importantly, the unique comparative approach allows us to understand how the basic functional modules underlying cellular physiology are assembled to achieve phenotypic diversity.
Eukaryotic cells segregate chromosomes in either "open" or "closed" mitosis, depending on whether the nuclear envelope breaks down or remains intact. Higher eukaryotes such as humans undergo open mitosis whereas many unicellular eukaryotes divide chromosomes without losing nucleocytoplasmic integrity (left). Similarly to higher eukaryotes and in stark contrast to its relative Schizosaccharomyces pombe, the fission yeast Schizosaccharomyces japonicus ruptures the nuclear envelope during mitosis (right).
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