Figure 2.

CELF2 promotes exon 3 skipping and decreases the protein expression of TREM2. (A) Western blot analysis of the fl-TREM2 minigene co-transfected with EGFP-fused CELF1 or CELF2 into HEK cells. Protein expression was detected using antibodies as indicated. EGFP-LacZ was used as a control. Bar chart shows TREM2 protein levels relative to Lamin B (arbitrary unit). Error bars represent the SD (n = 7). Tukey’s test was used for statistical evaluation. (B) HEK cells that stably express the fl-TREM2 minigene were transfected with EGFP-CELF2, and the EGFP-positive cells were separated from the EGFP-negative cells via fluorescence-activated cell sorting. The cells were subjected to western blot, using antibodies as indicated (lest panel). The box plot shows TREM2 protein expression levels relative to GAPDH (arbitrary units). The collected EGFP-positive and EGFP-negative cells were considered as a pair at each sorting, and the two-tailed paired t test was used for statistical analysis (n = 6). (C) RT-PCR products of TREM2 in THP-1 cells treated with siRNA and cycloheximide (CHX) were resolved by polyacrylamide gels (upper panel). The lower panel shows western blot results of CELF proteins in siRNA-treated THP-1 cells.