The molecular networks regulating basic physiological processes in a cell can be converted into mathematical equations (eg differential equations) and solved by a computer. The division cycle of eukaryotic cells is an important example of such a control system, and fission yeast is an excellent test organism for the computational modelling approach. The mathematical model is tested by simulating wild-type cells and many known cell cycle mutants. This paper describes an example where this approach is useful in understanding multiple rounds of DNA synthesis (endoreplication) in fission yeast cells that lack the main (B-type) mitotic cyclin, Cdc13. It is proposed that the key physiological variable driving progression through the cell cycle during balanced growth and division is the mass/DNA ratio, rather than the mass/nucleus ratio.
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http://dx.doi.org/10.1093/bfgp/2.4.298 | DOI Listing |
Cytoskeleton (Hoboken)
January 2025
Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo, Japan.
Cytokinesis in animal and fungal cells requires the contraction of actomyosin-based contractile rings formed in the division cortex of the cell during late mitosis. However, the detailed mechanism remains incompletely understood. Here, we aim to develop a novel cell-free system by encapsulating cell extracts obtained from fission yeast cells within lipid vesicles, which subsequently leads to the formation of a contractile ring-like structure inside the vesicles.
View Article and Find Full Text PDFNat Struct Mol Biol
January 2025
Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany.
Intron removal during pre-mRNA splicing is of extraordinary complexity and its disruption causes a vast number of genetic diseases in humans. While key steps of the canonical spliceosome cycle have been revealed by combined structure-function analyses, structural information on an aberrant spliceosome committed to premature disassembly is not available. Here, we report two cryo-electron microscopy structures of post-B spliceosome intermediates from Schizosaccharomyces pombe primed for disassembly.
View Article and Find Full Text PDFNat Commun
January 2025
Instituto de Biología Funcional y Genómica, Zacarías González 2, Salamanca, 37007, Spain.
Accurate gametogenesis requires the establishment of the telomere bouquet, an evolutionarily conserved, 3D chromosomal arrangement. In this spatial configuration, telomeres temporarily aggregate at the nuclear envelope during meiotic prophase, which facilitates chromosome pairing and recombination. The mechanisms governing the assembly of the telomere bouquet remain largely unexplored, primarily due to the challenges in visualizing and manipulating the bouquet.
View Article and Find Full Text PDFMol Biol Cell
January 2025
Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
The Munc13/UNC-13 family protein Ync13 is essential for septum integrity and cytokinesis in fission yeast. To further explore the mechanism of Ync13 functions, spontaneous suppressors of mutants, which can suppress the colony-formation defects and lysis phenotype of mutant cells, are isolated and characterized. One of the suppressor mutants, -, shows defects in the cytokinetic contractile ring constriction, septation, and daughter-cell separation, similar to mutant.
View Article and Find Full Text PDFFoods
December 2024
Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia.
In winemaking, malolactic fermentation (MLF), which converts L-malic acid to L-lactic acid, is often applied after the alcoholic fermentation stage to improve the sensory properties of the wine and its microbiological stability. MLF is usually performed by lactic acid bacteria, which, however, are sensitive to the conditions of alcoholic fermentation. Therefore, the development of wine yeast strains capable of both alcoholic fermentation and MLF is an important task.
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