When bigger is better: the role of polyploidy in organogenesis

Abstract

Defining how organ size is regulated, a process controlled by not only the number of cells but also the size of the cells, is a frontier in developmental biology. Large cells are produced by increasing DNA content or ploidy, a developmental strategy employed throughout the plant and animal kingdoms. The wide-spread use of polyploidy during cell differentiation makes it important to define how this hypertrophy contributes to organogenesis. I discuss here examples from a variety of animals and plants in which polyploidy controls organ size, the size and function of specific tissues within an organ, or the differentiated properties of cells. In addition, I highlight how polyploidy functions in wound healing and tissue regeneration.

Alterations in sarcomere function modify the hyperplastic to hypertrophic transition phase of mammalian cardiomyocyte development

“…Endoreplication has been shown to play a role in the regulation of cell size during organogenesis (28). In addition to regulating developmental growth, endoreplication is necessary for normal function of various mammalian cell types.…”

Myocardial Regeneration for Humans ― Modifying Biology and Manipulating Evolution ―

“…84 Into adulthood, multiple mammalian organs retain populations of polyploid cells, most notably the heart, 85,86 liver, 69,86,87 and skin. 88 Although these organs possess polyploid cells and have limited regenerative capacity, the relationship between ploidy and regenerative capacity of the organ remains unclear and seems highly variable.…”

“…69 The relationship between hepatocyte ploidy and regenerative capacity of the liver remains an intriguing area of ongoing research, as hepatocytes undergo chromatin reduction during extensive division and liver regeneration. 88 In comparison, the heart comprises cardiomyocytes that transition from single nuclei diploid cells in neonates to binucleated tetraploid adult cells. 69 Binucleated cardiomyocytes are typically unable to complete the cell cycle.…”

Genome management and mismanagement—cell-level opportunities and challenges of whole-genome duplication

“…The ability to generate endopolyploid cells seems to have re-evolved many times and is likely an important adaptation in those tissues or cell types where mitotic division would be deleterious for structural reasons, when rapid growth or large cell size are required, or to allow cell survival when DNA damage makes mitotic division untenable (for review, see Vinogradov et al 2001;Edgar et al 2014;Orr-Weaver 2015). Although there is clearly variation in the biology of endopolyploid cell types in different tissues or species, they do share several important consistent features, such as increased cell size and perhaps altered growth potential and physiology, which we discuss below (e.g., see Levin 1983;Butterfass 1987;Galitski et al 1999;Sugimoto-Shirasu and Roberts 2003;Barow 2006;Orr-Weaver 2015;Scholes and Paige 2015).…”