The total RNA was extracted from the mouse liver tissue， and the cDNA was obtained by reverse transcription. PCR was utilized to amplify the coding fragment for the NR1D1 gene， and the NR1D1 CDS fragment was then ligated into the pcDNA3.1 vector by homologous recombination reactions. The recombinant plasmids were identified by restriction enzyme digestion and sequencing， and the recombinant plasmid was named as pcDNA3.1-NR1D1， and then the pcDNA3.1 plasmids and pcDNA3.1-NR1D1 recombinant plasmids were transfected respectively into the HEK293T cells and named as control group and pcDNA3.1-NR1D1 transfection group.After 48 h，the extraction of total RNA and total protein from cell samples were performed，and the expression levels of NR1D1 mRNA and protein were detected by real-time fluorescence quantitative PCR（RT-qPCR） and Western blotting methods， respectively. Meanwhile， the similarities of NR1D1 coding sequence（CDS） between the mice and other species were analyzed by DNAStar software and MEGA7 software， and the phylogenetic trees were constructed. In addition， the amino acid composition，hydrophilicity/hydrophobicity， transmembrane regions， signal peptides， secondary and tertiary structures of the NR1D1 protein were analyzed with online tools， such as ExPASy， ProtScale， SingalP5.0， TMHMM-2.0， PhosphoSitePlus^?， SOPMA and SWISS-MODEL.

The restriction enzyme digestion and sequencing results showed that the overexpression vector pcDNA3.1-NR1D1 was successfully constructed. Compared with control group， the expression levels of NR1D1 mRNA and protein in the cells in pcDNA3.1-NR1D1 transfection group were significantly increased （P<0.01）. In addition， the bioinformatics analysis revealed that the similarities of the Mus musculus NR1D1 CDS region with Homo sapiens， Rattus norvegicus， Cricetulus griseus， Pan troglodytes， Oryctolagus cuniculus， Canis lupus familiaris， Sus scrofa， Equus caballus， Bos taurus， Ovis aries， Capra hircus， Felis catus and Danio rerio were 90.0%， 94.8%， 86.5%， 90%， 89.6%， 88.3%， 89.7%， 89.8%， 88.8%， 89.1%， 89.1% and 65.1%， respectively. The phylogenetic tree showed that the Mus musculus NR1D1 gene was the closest genetically to the Cricetulus griseus and Rattus norvegicus， and the most distant from Danio rerio. Mouse NR1D1 protein was a hydrophobic basic protein， not a secreted protein or a transmembrane protein， which contained 12 phosphorylation sites and 10 ubiquitination sites. The secondary structure of mouse NR1D1 protein included 54.63% random coil， 26.50% α-helix， 12.68% extended chain， and 6.18% β-turn， and NR1D1 protein had larger similarity and less variation in tertiary structure compared with the human.

The mouse NR1D1 gene overexpression vector pcDNA3.1-NR1D1 is successfully constructed， and its overexpression efficiency is verified in the HEK293T cells， which provide the basis for further research on the function of NR1D1 gene and protein.