Objective To get the full-length presenilin-1 (PSEN1) cDNA encoding sequence and analyze itsmolecular characteristics. Methods Full-length PSEN1 cDNA was cloned from total RNA from brain tissue of tree shrewby RT-PCR and RACE-PCR. The molecular characteristics were compared with PSEN1 in other mammals and evaluatedusing biology softwares such as DNAMAN, MEGA and others. Quantitative reverse transcription PCR and western blotassays were used to examine the mRNA and protein expression pattern of PSEN1 in various tissues of tree shrew. ResultsThe open reading frame sequence of PSEN1 was 1128 bp and encoded 375 amino acids. We constructed a phylogeneticfamily tree and compared their PSEN1 amino acid sequences. Tree shrew PSEN1 was closer to humans and non-humanprimates than mouse and rat. The expression of PSEN1 mRNA and protein was obviously higher in the brain than that ofother organ tissues. Conclusions We successfully cloned the PSEN1 gene in tree shrew and provided comparative analysiswith other species. These findings provide a theoretical basis for further study on the function of this gene and the establishment of animal models of Alzheimer’s disease (AD).