Antisense RNA to the first N-glycosylation gene, ALG7, inhibits proteins N-glycosylation and secretion by Xenopus oocytes

Abstract

N-glycosylation has been shown to affect the rate of glycoprotein transport through the secretory pathway. In order to identify the critical components in the N-glycosylation pathway that directly influence protein secretion, studies were undertaken concerning the effects of downregulation of the first gene in the dolichol pathway, ALG7, on the synthesis, glycosylation, and secretion of native and heterologous proteins by Xenopus laevis oocytes. The strategy involved the use of ALG7 antisense RNA (asRNA) to lower the effective abundance of the ALG7 protein in the oocyte. The results demonstrated that there was an inverse dose-response relationship between ALG7 asRNA and the amount of protein secreted and the fraction of secreted protein which was N-glycosylated. These effects were also observed for heterologously expressed rat salivary a-amylase. Since ALG7 asRNA did not inhibit the overall protein synthesis,it was concluded that downregulation of ALG7 expression directly lowered protein export.