Detection of Insig-1 mRNA and protein expression in INS-1-Insig-1 stable cells. An Insig-1 stable cell line was generated by overexpression of Insig-1 in INS-1 cells, Insig-1 gene and protein expression were confirmed by RT-PCR and Western blot analysis, respectively. A) A mouse specific anti-Insig-1 primary antibody was used to detect mouse Insig-1 protein by Western blot analysis. GAPDH was used as control for protein loading. B) Relative expression of Insig-1 protein compared to GAPDH. 1, 2 and 3 represent control INS-1 cells, INS-1-Insig-1 cell line 1 and 2, respectively. *P < 0.05. C) Mouse Insig-1 mRNA expression was detected by RT-PCR, INS-1-Insig-1 cell line 2 is shown and used for further experiments. M: Marker.