Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by loss of motor neurons in the spinal cord (1). SMA is caused by deletion or loss-of-function mutations in the SMN (Survival of Motor Neuron) gene (2). Gemin5, the protein product of human chromosome 5q33.3 (3), associates directly with SMN and is a part of the SMN complex containing Gemin2, Gemin3, Gemin4 and Gemin6 as well as several spliceosomal snRNP proteins (2,4). The SMN complex plays an essential role in spliceosomal snRNP assembly in the cytoplasm and is required for pre-mRNA splicing of the nucleus (2). The SMN complex is found in both the cytoplasm and the nucleus (2). The nuclear form is concentrated in subnuclear bodies called gems (Gemini of the coiled bodies) (2,5,6). Gemin5 interacts with several snRNP core proteins including SmB, SmD1, SmD2, SmD3 and SmE (7). The amino terminal half of Gemin5 contains 13 WD repeat domains and a coiled-coil motif near the C-terminus (7).