Asymmetric cell division in land plants and algae: the driving force for differentiation

• Published in: Nature reviews. Molecular cell biology Vol. 12; no. 3; pp. 177 - 188
• Main Authors: De Smet, Ive, Beeckman, Tom
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2011; Nature Publishing Group
• Subjects: 631/449/2653/2654; 631/449/2653/2656; 631/449/448/1358; 85; 86; Algae; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - growth & development; Biochemistry; Biomedical and Life Sciences; Cancer Research; Cell Biology; Cell Cycle; Cell Differentiation; Cell Division; Cell Polarity; Developmental Biology; Fucus - cytology; Genetic aspects; Life Sciences; Models, Biological; Physiological aspects; Plant Cells; Plant Development; Plants - genetics; review-article; Stem Cells; Stramenopiles - cytology; Belgium; United Kingdom
• ISSN: 1471-0072; 1471-0080
• DOI: 10.1038/nrm3064

Key Points Asymmetric cell division is essential in many organisms to generate cell diversity and tissue patterns and to maintain pools of stem cells. In plants and multicellular algae, asymmetric cell division is of particular importance, as their post-embryonic growth is based on de novo formation of cell types, tissues and even entirely new organs. Daughter cells, which can be initially equivalent or different in size and/or molecular composition, can achieve different cell fates through intrinsic or extrinsic factors that convey positional information. These seemingly distinct mechanisms can rarely be separated, and it is becoming clear that every asymmetric cell division depends on both extrinsic and intrinsic factors simultaneously. Asymmetric cell division in plants involves numerous steps: specification of a subset of cells that will undergo asymmetric cell division; cellular events (such as establishment of polarity, polar localization of proteins, establishment of gradients, correct positioning of the nucleus, polar accumulation of the cytoplasm and formation of the preprophase band, spindle and cell plate); and the asymmetrical distribution and expression of cell fate determinants. Together, these control the identity and future development of both daughter cells into a differentiated tissue or new organ. However, not all steps are necessarily present in every asymmetric cell division process. In animals, the cell cycle has been linked to asymmetric localization of cell fate determinants and, consistently, the regulation of asymmetric cell division needs to be precisely coordinated with cell cycle progression in plants as well. Various developmental processes require asymmetric cell division and use similar, or even the same, mechanisms and/or conserved molecular players. Asymmetric cell division is essential in many organisms, as it generates different cell types and maintains stem cell pools. The identification of key molecular players, and a comparison with the pathways in animals, allows a better mechanistic understanding of asymmetric cell division in plants and algae. Asymmetric cell division generates two cells with different fates and has an important role in plant development. It produces distinct cell types and new organs, and maintains stem cell niches. To handle the constraints of having immobile cells, plants possess numerous unique features to obtain asymmetry, such as specific regulators of intrinsic polarity. Although several components have not yet been identified, new findings, together with knowledge from different developmental systems, now allow us to take an important step towards a mechanistic overview of asymmetric cell division in plants and algae. Strikingly, several key regulators are used for different developmental processes, and common mechanisms can be recognized.