Quantification of mRNAs encoding proteins of the glycosphingolipid catabolism in mouse models of GM2 gangliosidoses and sphingolipid activator protein precursor (prosaposin) deficiency.

We have investigated the mRNA amounts of six lysosomal proteins (beta-hexosaminidase alpha- and beta-subunit, sphingolipid activator protein precursor, GM2 activator protein, lysosomal sialidase, beta-glucocerebrosidase) involved in the degradation of glycosphingolipids. We analyzed extracts from brain tissues of mouse models for lysosomal storage diseases, i.e., the GM2 gangliosidoses and the deficiency of the sphingolipid activator protein precursor (prosaposin). The mRNA levels were quantified by real-time reverse transcription-polymerase chain reaction. Although storage of the respective lysosomal proteins has been reported in human and mice, no increase of their mRNA amounts could be detected here. Our results indicate that there is no transcriptional upregulation of lysosomal proteins in the examined neuronal storage disorders.