FIGURE 4:

Full-length Htt is required for perinuclear organelle positioning. (A) Scrambled control (left) or Htt RNAi cells (right) were transfected with full-length Htt and stained for Htt to identify transfected cells and LAMP1. Asterisks identify transfected cells in LAMP1 panels. Scale bar = 20 μm. (C) Schematic of Htt full-length, Htt aa1–1472, and Htt aa1–480. The polyglutamine repeat region begins at aa17 (orange), and there are 36 predicted HEAT repeats spanning the length of the peptide (dark purple speckled). HAP1, which associates with kinesin and dynactin, binds to the Htt N terminus, dynein binds aa601–698, and HAP40 binding site resides at the C terminus. (D) Scrambled control (left side) or Htt RNAi (right side) cells transfected with no DNA, Htt1–480, Htt1–1472, or Htt full-length (Htt FL) were scored for perinuclear (blue), dispersed (red), or dispersed with additional cortical accumulations of LE/lysosomes (green), visualized by staining for LAMP1. To illustrate the change in phenotypes at different Htt construct expression levels, the transfected cells were binned into low or medium expressors vs. high expressors; expression level is signified by the gray ramp; n ≥ 64 cells for each condition. Error bars, ±95% CI.