Heterogeneity of gene expression and rarity of replication hampers molecular analysis of β-cell mass restoration in the adult pancreas. Single-cell RNA sequencing of murine pancreases was conducted, with or without partial pancreatectomy, to show transcriptional dynamics in the β-cell replication process. The transcriptional trait describes heterogeneity of Ins1-expressing β-cells, one cluster of replicating β-cells with high expression of cell proliferation markers Pcna and Mki67 was observed. Transient activation of ER stress responders (like Atf6 and Hspa5) was also seen during the transition to replication, along with elevated expression of tumor suppressors – such as Trp53, Rb1 and Brca1 – and DNA damage responders, like Atm, Atr, Rad51, Chek1 and Chek2. This shows the fine balance of cell cycle progression and protection from DNA damage. Taken together, these results provide a high resolution map depicting a sophisticated genetic circuit for replication of the β-cells.
