Dynamic expression of lamin B1 during adult neurogenesis in the vertebrate brain

In mammals, specific brain regions such as the dentate gyrus (DG) of the hippocampus and the subventricular zone (SVZ) of the lateral ventricles harbor adult neural stem/progenitor cells (ANSPCs) that give rise to new neurons and contribute to structural and functional brain plasticity. In contrast, other vertebrates such as salamanders and zebrafish exhibit a widely distributed neurogenic niches throughout the brain, suggesting a greater neurogenic capacity in adulthood. However, the mechanisms underlying this divergence in neurogenic potential among vertebrates remain elusive. To address this, we examined the expression dynamics of a critical epigenetic regulator for the long-term maintenance of murine ANSPCs, lamin B1, during adult neurogenesis across the vertebrate spectrum.

Lamin B1 expression patterns during adult neurogenesis are conserved among mammals including mouse, naked mole-rat, and ferret. However, these patterns differ between mammals and anamniotes. In mammals, neural stem cells and neuroblasts exhibited higher lamin B1 levels, and differentiated neurons possessed lower lamin B1 levels. On the other hand, anamniotes showed the opposite patterns of lamin B1 expression, with higher levels in neurons compared to stem cells.

Our study shows that the lamin B1 expression pattern during adult neurogenesis differs between species, and that changes in lamin B1 protein sequence may contribute to the differences in lamin B1 expression patterns. This study highlights potential differences in cell-autonomous epigenetic regulation in the maintenance of ANSPC pools in the adult brain among species.