1 2 An aging-independent replicative lifespan in a symmetrically dividing eukaryote 3 4 Eric C. Spiveya,b,*, Stephen K. Jones Jr.a,b,*, James R. Rybarskia, Fatema A. Saifuddina, and Ilya 5 J. Finkelsteina,b,c,1 6 7 a Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 8 b Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 9 c Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 10 * Equal contribution 11 1 Correspondence:
[email protected], Department of Molecular Biosciences, The 12 University of Texas at Austin, Austin, TX 78712. Office: 512-471-1394 13 Abstract 14 The replicative lifespan (RLS) of a cell—defined as the number of cell divisions before death— 15 has informed our understanding of the mechanisms of cellular aging. However, little is known 16 about aging and longevity in symmetrically dividing eukaryotic cells because most prior studies 17 have used budding yeast for RLS studies. Here, we describe a multiplexed fission yeast lifespan 18 micro-dissector (multFYLM) and an associated image processing pipeline for performing high- 19 throughput and automated single-cell micro-dissection. Using the multFYLM, we observe 20 continuous replication of hundreds of individual fission yeast cells for over seventy-five 21 generations. Surprisingly, cells die without the classic hallmarks of cellular aging, such as 22 progressive changes in size, doubling time, or sibling health. Genetic perturbations and drugs can 23 extend the RLS via an aging-independent mechanism. Using a quantitative model to analyze 24 these results, we conclude that fission yeast does not age and that cellular aging and replicative 25 lifespan can be uncoupled in a eukaryotic cell.