Quantification of the Gemin2 and Smn protein levels in spinal cord of 5-month-old Gemin2 and Smn heterozygous deficient mice. Gemin2 and Smn protein levels in spinal cord of wild-type, Smn+/−, Smn+/−/Gemin2+/−, and Gemin2+/− mice were compared by quantification of the intensities of Gemin2 and Smn immunoreactive bands from Western blots using a Gemin2-specific antiserum and a monoclonal anti-Smn antibody. Similar protein expression of Gemin2 and Smn was observed in spinal cord tissue of wild-type and Gemin2+/− mice. Only 50% of Smn (*, white bar) and Gemin2 (*, gray bar) protein was expressed in spinal cord of Smn+/− mice. Immunodetection of Gemin2 in spinal cord of Smn+/−/Gemin2+/− mice showed a stronger reduction (−75%) compared with Smn (−50%) (P < 0.05).