The lifespan quantitative trait locus gene Securin controls hematopoietic progenitor cell function

The percentage of murine hematopoietic stem and progenitor cells, which present with a loss of function upon treatment with the genotoxic agent hydroxyurea, is inversely correlated to the mean lifespan of inbred mice, including the long-lived C57B116 and short-lived DBA/2 strains. Quantitative trait locus mapping in BXD recombinant inbred strains identified a region spanning 12.5 cM on the proximal part of chromosome 11 linked to both the percentage of dysfunctional hematopoietic stem and progenitor cells as well as regulation of lifespan. By generating and analyzing reciprocal congenic mice for this locus, we demonstrate that this region indeed determines the sensitivity of hematopoietic stem and progenitor cells to hydroxyurea. These cells do not present, as previously anticipated, with differences in cell cycle distribution; neither do they present with changes in the frequency of cells undergoing apoptosis, senescence, replication stalling and re-initiation activity, excluding the possibility that variations in proliferation, replication or viability underlie the distinct response of these cells from the congenic and parental strains. An epigenetic aging dock in blood cells was accelerated in C57BL/6 mice congenic for the DBA/2 version of the locus. We verified pituitary tumor-transforming gene1 (Pttg1)/Securin as the quantitative trait gene regulating the differential response of hematopoietic stem and progenitor cells to hydroxyurea treatment and which might therefore be linked to the regulation of lifespan.