Fig. 6

Effects of ELOVL3 promoter region variant and expression on duck fat deposition and fatty acid composition. A Different lengths of a fragment of ELOVL3 promoter region cloned by PCR. B Relative luciferase activity of different promoter fragments. F1–F7, fluorescence activity values detected after transfection of ICP1 cells with fluorescence vectors containing promoter truncated fragments of different lengths, using pRL-TK as reference (n = 3 biological replicates). C Relative luciferase activity of the mallard and Pekin duck core promoter haplotype vectors (n = 3 biological replicates). D Schematic diagram of transcription factor prediction which was affected by candidate causal SNP in core promoter regions. The solid line in the figure indicates the normal binding of transcription factors, and the dotted line indicates the reduced binding ability of transcription factors in the prediction results. The green line indicates the transcription factors that have not changed their binding ability before and after the mutation, and the red line indicates the transcription factors that have changed their binding ability after the mutation. E The relative luciferase activity of the mutant-type (− 619 > G-) haplotype and the wild-type (− 619 > A-) core promoter haplotype vectors in the ICP1 cell line (n = 3 biological replicates). Three luciferase reporter gene constructs were generated. They share identical backbone sequences except for the polymorphisms shown on the left. F The effect of transcription factor HLF on the relative luciferase activity (n = 3 biological replicates). G mRNA levels of ELOVL3 were analyzed by Q-PCR in ELOVL3^OE and ELOVL3^NC cells before and after induction (n = 3 biological replicates). H Oil Red O staining to assess lipid accumulation at day 2 post-induction for ELOVL3^NC and ELOVL3^OE cells. The scale bar represents 20 μm (n = 3 biological replicates). I Cell Counting Kit-8 assay (CCK8) examines the proliferation of ELOVL3^OE and ELOVL3^NC cells over 5 days. Each cell number is counted by the standard curve established by CCK8 of the respective cells (n = 6 biological replicates). J The lipid droplet content of ELOVL3^OE and ELOVL3^NC cells obtained by Oil Red O staining and extraction methods (n = 3 biological replicates). K mRNA levels of PPARγ and FABP4 were analyzed by Q-PCR before and post-induction (n = 3 biological replicates). L Gas chromatography to assess fatty acid composition at day 2 post-induction for ELOVL3^NC and ELOVL3^OE cells. Data are shown as mean ± SD of three biological replicates. An independent sample t-test was used to analyze the statistical differences between groups. The level of significance is presented as ns (not significant), ∗ (P < 0.05), ∗  ∗ (P < 0.01), ∗  ∗  ∗ (P < 0.001)