Effect of elongation factor 1α promoter and SUMF1 over in vitro expression of N-acetylgalactosamine-6-sulfate sulfatase

Morquio A is an autosomal recessive disease caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS), leading to the lysosomal accumulation of keratan-sulfate and chondroitin-6-sulfate. We evaluated in HEK293 cells the effect of the cytomegalovirus immediate early enhancer/promoter (CMV) or the elongation factor 1α (EF1α) promoters, and the coexpression with the sulfatase modifying factor 1 (SUMF1) on GALNS activity. Four days postransfection GALNS activity in transfected cells with CMV-pIRES-GALNS reached a plateau, whereas in cells transfected with EF1α-pIRES-GALNS continued to increase until day 8. Co-transfection with pCXN-SUMF1 showed an increment up to 2.6-fold in GALNS activity. Finally, computational analysis of transcription factor binding-sites and CpG islands showed that EF1α promoter has long CpG islands and high-density binding-sites for Sp1 compared to CMV. These results show the advantage of the SUMF1 coexpression on GALNS activity and indicate a considerable effect on the expression stability using EF1α promoter compared to CMV.