1. Academic Validation
  2. Polyploidy in Xenopus lowers metabolic rate by decreasing total cell surface area

Polyploidy in Xenopus lowers metabolic rate by decreasing total cell surface area

  • Curr Biol. 2023 Apr 14;S0960-9822(23)00391-3. doi: 10.1016/j.cub.2023.03.071.
Clotilde Cadart 1 Julianne Bartz 2 Gillian Oaks 2 Martin Ziyuan Liu 2 Rebecca Heald 3
Affiliations

Affiliations

  • 1 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA. Electronic address: clotilde.cadart@berkeley.edu.
  • 2 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA.
  • 3 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA. Electronic address: bheald@berkeley.edu.
Abstract

Although polyploidization is frequent in development, Cancer, and evolution, impacts on animal metabolism are poorly understood. In Xenopus frogs, the number of genome copies (ploidy) varies across species and can be manipulated within a species. Here, we show that triploid tadpoles contain fewer, larger cells than diploids and consume oxygen at a lower rate. Drug treatments revealed that the major processes accounting for tadpole energy expenditure include cell proliferation, biosynthesis, and maintenance of plasma membrane potential. While inhibiting cell proliferation did not abolish the oxygen consumption difference between diploids and triploids, treatments that altered cellular biosynthesis or electrical potential did. Combining these results with a simple mathematical framework, we propose that the decrease in total cell surface area lowered production and activity of plasma membrane components including the Na+/K+ ATPase, reducing energy consumption in triploids. Comparison of Xenopus species that evolved through polyploidization revealed that metabolic differences emerged during development when cell size scaled with genome size. Thus, ploidy affects metabolism by altering the cell surface area to volume ratio in a multicellular organism.

Keywords

Kleiber’s law; Xenopus; cell size; energy budget; metabolism; oxygen consumption rate; polyploidy; scaling.

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