Effects of individual segmental trisomies of human chromosome 21 syntenic regions on hippocampal long-term potentiation and cognitive behaviors in mice

As the genomic basis for Down syndrome (DS), human trisomy 21 is the most common genetic cause of intellectual disability in children and young people. The genomic regions on human chromosome 21 (Hsa21) are syntenic to three regions in the mouse genome, located on mouse chromosome 10 (Mmu10), Mmu16, and Mmu17. Recently, we have developed three new mouse models using chromosome engineering carrying the genotypes of Dp(10)1Yey/+, Dp(16)1Yey/+, or Dp(17)1Yey/+, which harbor a duplication spanning the entire Hsa21 syntenic region on Mmu10, Mmu16, or Mmu17, respectively. In this study, we analyzed the hippocampal long-term potentiation (LTP) and cognitive behaviors of these models. Our results show that, while the genotype of Dp(17)1Yey/+ results in abnormal hippocampal LTP, the genotype of Dp(16)1Yey/+ leads to both abnormal hippocampal LTP and impaired learning/memory. Therefore, these mutant mice can serve as powerful tools for further understanding the mechanism underlying cognitively relevant phenotypes associated with DS, particularly the impacts of different syntenic regions on these phenotypes.

Research Highlights
► Models trisomic for the entire human chromosome 21 syntenic region on mouse chromosome 10, 16, or 17.
► First postnatal phenotypes of these mouse models carrying the individual trisomies.
► The trisomy on mouse chromosome 10 leads to normal LTP and cognitive behaviors.
► The trisomy on mouse chromosome 16 causes impairment in LTP and cognitive behaviors.
► The trisomy on mouse chromosome 17 causes impairment in LTP not cognitive behaviors.