Endocytosis in wild-type, heterozygous and homozygous Cb Cln3Δex7/8 cells Dextran-FITC uptake in wild-type, heterozygous and homozygous CbCln3Δex7/8 precursor cells is shown. In wild-type (CbCln3+/+, left panel) and heterozygous (CbCln3+/Δex7/8, middle panel) cells, dextran-FITC label was observed in a perinuclear-clustered vesicular pattern with scattered labeled vesicles also present in the periphery. In contrast, dextran-FITC label of homozygous mutant (CbCln3Δex7/8/Δex7/8, right panel) cells was reduced overall and exhibited smaller stained vesicles with less perinuclear clustering. Confocal images were captured with identical exposure settings. 40 × magnification.