Department of Radiation Biology, Oslo University Hospital, Oslo, Norway.
Department of Biosciences, University of Oslo, Oslo, Norway.
Open Biol. 2021 Aug;11(8):210116. doi: 10.1098/rsob.210116. Epub 2021 Aug 4.
Cellular asymmetry plays a major role in the ageing and evolution of multicellular organisms. However, it remains unknown how the cell distinguishes 'old' from 'new' and whether asymmetry is an attribute of highly specialized cells or a feature inherent in all cells. Here, we investigate the segregation of three asymmetric features: old and new DNA, the spindle pole body (SPB, the centrosome analogue) and the old and new cell ends, using a simple unicellular eukaryote, . To our knowledge, this is the first study exploring three asymmetric features in the same cells. We show that of the three chromosomes of , chromosome I containing the new parental strand, preferentially segregated to the cells inheriting the old cell end. Furthermore, the new SPB also preferentially segregated to the cells inheriting the old end. Our results suggest that the ability to distinguish 'old' from 'new' and to segregate DNA asymmetrically are inherent features even in simple unicellular eukaryotes.
细胞不对称性在多细胞生物的衰老和进化中起着重要作用。然而，目前尚不清楚细胞如何区分“旧”和“新”，以及不对称性是高度特化细胞的属性还是所有细胞固有的特征。在这里，我们使用一种简单的单细胞真核生物来研究三个不对称特征的分离：旧和新的 DNA、纺锤体极体（SPB，中心体类似物）以及旧和新的细胞末端。据我们所知，这是首次在同一细胞中探索三个不对称特征的研究。我们表明，在含有新亲本链的三个 染色体中，I 染色体优先分配到继承旧细胞末端的细胞中。此外，新的 SPB 也优先分配到继承旧端的细胞中。我们的结果表明，区分“旧”和“新”以及不对称地分配 DNA 的能力是即使在简单的单细胞真核生物中也是固有的特征。
