Article
- The EMBO Journal (2008) 27, 1309 - 1320
- doi:10.1038/emboj.2008.72
Published online: 10 April 2008
Subject Categories:
Quantitative proliferation dynamics and random chromosome segregation of hair follicle stem cells
Sanjeev K Waghmare1, Rajat Bansal1, Jayhun Lee1,a, Ying V Zhang1,a, David J McDermitt1 and Tudorita Tumbar1
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
Correspondence to:
Tudorita Tumbar, Department of Molecular Biology and Genetics, Cornell University, Biotech 258, Ithaca, NY 14850, USA. Tel.: +1 607 255 6542; Fax: +1 607 255 6249; E-mail: tt252@cornell.edu
aThese authors contributed equally to this work
Received 17 December 2007; Accepted 17 March 2008
Abstract
Regulation of stem cell (SC) proliferation is central to tissue homoeostasis, injury repair, and cancer development. Accumulation of replication errors in SCs is limited by either infrequent division and/or by chromosome sorting to retain preferentially the oldest 'immortal' DNA strand. The frequency of SC divisions and the chromosome-sorting phenomenon are difficult to examine accurately with existing methods. To address this question, we developed a strategy to count divisions of hair follicle (HF) SCs over time, and provide the first quantitative proliferation history of a tissue SC during its normal homoeostasis. We uncovered an unexpectedly high cellular turnover in the SC compartment in one round of activation. Our study provides quantitative data in support of the long-standing infrequent SC division model, and shows that HF SCs do not retain the older DNA strands or sort their chromosome. This new ability to count divisions in vivo has relevance for obtaining basic knowledge of tissue kinetics.
Keywords:
- hair follicle stem cells,
- immortal strand hypothesis,
- label retaining cells,
- proliferation history
