Mekayla A. Storer

DNA deoxyribonucleic acid H3K27me3 histone 3 lysine 27 trimethylation H3K9me2 histone 3 lysine 9 dimethylation H3K9me3 histone 3 lysine 9 trimethylation RNA ribonucleic acid TSSs transcription start sites Introduction During early development as cell transition from multipotency to committed cell fates, the chromatin remains accessible so that cells can respond to differentiation cues and activate genes required for differentiation and acquisition of identity.

Highlights • Senescent neural precursor cells accumulate in the hippocampus with age • Senescent precursor accumulation is coincident with declining adult neurogenesis • Ablating senescent precursors increases precursor proliferation and neurogenesis • Ablating senescent precursors improves hippocampus-dependent spatial memory Summary Senescent cells are responsible, in part, for tissue decline during aging.

Highlights • Pdgfra-expressing mesenchymal cells from uninjured digits establish the blastema • Adult digit tip regeneration is distinct from embryonic digit development • The blastema state is environmentally determined • The regenerative environment enables mesenchymal lineage plasticity Summary Here, we investigate the origin and nature of blastema cells that regenerate the adult murine digit tip.