Fragile X syndrome (FXS) is a genetic mental retardation disease, with incidence second only to trisomy 21 syndrome. Fragile X mental retardation protein(FMRP), is the causative factor of FXS and encoded by the Fragile X mental retardation1(FMR1)gene, which is widely expressed in cells of the nerve, muscle, and testes. Fragile X related protein 1 (FXR1P) is encoded by a homologous gene to FMR1——Fragile X related gene 1 (FXR1) and can interact with proteins and RNAs. Many illnesses were involved in the altered expression of FXR1. To understand the biological effect of the interaction between FXR1P and CMAS, we constructed a FXR1 overexpression vector and investigated its expression in PC12 (the rat pheochromocytoma) cells and VSMC (vascular smooth muscle cell) and the effect of the overexpression on cell morphology and several cell processes related to CMP-N-acetylneuraminic acid synthetase (CMAS) activity. We demonstrate that the overexpression of FXR1 gene can increase activity of CMAS in PC12 cells and provide a certain degree growth protection for that cells. Thus, it suggests FXR1P is a tissue-specific regulator to alter the concentration of GM1 in PC12 cells, but not in VSMC.