Abstract
Complete and robust human genome duplication requires loading minichromosome maintenance (MCM) helicase complexes at many DNA replication origins, an essential process termed origin licensing. Licensing is restricted to G1 phase of the cell cycle, but G1 length varies widely among cell types. Using quantitative single-cell analyses, we found that pluripotent stem cells with naturally short G1 phases load MCM much faster than their isogenic differentiated counterparts with long G1 phases. During the earliest stages of differentiation toward all lineages, MCM loading slows concurrently with G1 lengthening, revealing developmental control of MCM loading. In contrast, ectopic Cyclin E overproduction uncouples short G1 from fast MCM loading. Rapid licensing in stem cells is caused by accumulation of the MCM loading protein, Cdt1. Prematurely slowing MCM loading in pluripotent cells not only lengthens G1 but also accelerates differentiation. Thus, rapid origin licensing is an intrinsic characteristic of stem cells that contributes to pluripotency maintenance.
| Original language | English (US) |
|---|---|
| Article number | e30473 |
| Journal | eLife |
| Volume | 6 |
| DOIs | |
| State | Published - Nov 17 2017 |
Bibliographical note
Funding Information:National Science Foundation Graduate Student Research Fellowship DGE1144081 Jacob Peter Matson National Institutes of Health Training Grant T32CA009138 Ryan M Baxley University of Minnesota Tulloch Chair in Stem Cell Biology, Genetics and Genomics Jakub Tolar National Institutes of Health Research Grant GM074917 Anja-Katrin Bielinsky W. M. Keck Foundation Research Grant Jeremy E Purvis Jeanette Gowen Cook National Institutes of Health Research Grant DP2HD091800 Jeremy E Purvis National Institutes of Health Research Grant GM083024 Jeanette Gowen Cook National Institutes of Health Research Grant GM102413 Jeanette Gowen Cook
Funding Information:
We are grateful to Ran Kafri for advice on ergodic rate analysis. We thank Jeffrey Jones for managerial assistance, Dr. Sam Wolff for microscopy assistance, the UNC Human Pluripotent Stem Cell Core stem cell culture assistance and A Adams, S Wong, M Consuegra, S Goraya, and S Sisk for technical assistance. We also thank Dr. Robert Duronio, Dr. Michael Emanuele, and the Cook lab for helpful discussions. We thank Ron McElmurry and Megan Riddle at the University of Minnesota for conducting teratoma assays, and the Cytogenomics Shared Resource (P30 CA077598) at the University of Minnesota Masonic Cancer Center for karyotype analysis. The UNC Flow Cytometry Core Facility is supported in part by P30 CA016086. This work was supported by a fellowship from the NSF (DGE-1144081) to JPM and by grants from the NIH to JGC (GM083024 and GM102413), RMB (T32-CA009138) JEP (DP2-HD091800) and AKB (GM074917). Additional funding was provided by the WM Keck foundation to JEP and JGC; JT is supported by the Tulloch Chair in Stem Cell Biology, Genetics and Genomics at the University of Minnesota.
Publisher Copyright:
© Matson et al.