The expression of SMN1, MART3, GLE1 and FUS genes in spinal muscular atrophy.

INTRODUCTION: Spinal muscular atrophy (SMA) is one of the most common genetic causes of death in infants due to a mutation of the motor neuron 1 (SMN1) gene. The SMN1 gene encodes for the multifunctional SMN protein. SMN has been shown to be implicated in pre-mRNA splicing, mRNA transport and translational control. Also other mRNA processing proteins, such as GLE1, Marten (MART3) and Fused in Sarcoma (FUS), have been linked to neurodegenerative diseases. The aim of the study was to determine the expression of SMN, GLE1, MART3 and FUS genes in cell lines of the fibroblasts derived from SMA patients and normal controls.

MATERIAL AND METHODS: Total RNA was extracted from purchased fibroblasts acquired from three SMA type I patients and fibroblasts of three age-matched healthy controls. The RNA was then subjected to qPCR analysis using primers specific for the GLE1, MART3, FUS and SMN1 genes vs. GAPDH as internal control gene.

RESULTS: SMN1 mRNA levels were at least x10 lower in fibroblasts of SMA patients compared to controls. Gle1 and MART3 gene expression was x2 downregulated whereas FUS mRNA levels appeared to be x3 upregulated in SMA cells when compared to controls. We found a high correlation between FUS gene expression level to the SMN1 at gene expression level of fibroblast cell lines of SMA type I patients (r = 0.994, p < 0.0001).

CONCLUSIONS: Our preliminary data show an intriguing expression profile of Gle1, MART3 and FUS genes in SMA, and suggest a critical role of FUS protein in the SMA pathogenesis.