Two-dimensional gel analysis of proteins from human trisomy 21 fetal liver tissue after DEAE-Sepharose chromatography.

Isoelectrofocusing two-dimensional polyacrylamide gel electrophoresis (IEF-2D-PAGE) offers the opportunity to detect typical alterations in the protein pattern from directly prepared liver tissue of fetuses with trisomy 21 and normal controls. The fractionation of the cell lysate by differential centrifugation into various subcellular components (nuclei, membranes, polyribosomes, cytoplasmic proteins) and fractionation of the proteins through DEAE-Sepharose chromatography allows detection of protein differences. In the 19th week of pregnancy it is possible to establish only three differences in the protein patterns between liver tissue from trisomy 21-fetuses and normal controls. All three proteins are synthesized in euploid controls at a higher level than in trisomy 21-liver tissue and are supposed to be consequences of primary gene dosage effects. The molecular mass of the individual proteins ranges from 14 kdaltons to 31 kdaltons. The data reported here raise the question whether some of the differences found by others represent different gene expression of cells under tissue culture conditions and/or of cells derived from different tissues, or developmental stages.