Figure 3

Domain 4 of CCN1-Fc is required to induce CCN1 pre-mRNA splicing. (A) INA-6 cells were incubated with either 2.5 μg/ml recombinant CCN1-Fc full-length protein, or an equivalent amount of truncated CCN1 isoforms (CCN1-Fc 1-3, CCN1-Fc 1-2, and CCN1-Fc 1). Semi-quantitative PCR with intron-containing CCN1 primers showed that exposure to truncated CCN1 proteins comprising domains 1, 1-2, or 1-3 did not induce complete CCN1 mRNA splicing. (B) Splicing of CCN1 pre-mRNA induced by 2.5 μg/ml full-length CCN1-Fc was reversed by GRGDSP peptide (50 μg/ml in culture media) but not by addition of the control peptide GRADSP. One representative experiment out of three is shown.