Fig. 3.

Mapping of htt N-terminal cleavage. a Antibody mapping of mhtt proteolytic cleavage in htt-N233-82Q-transfected cells (+) and as control nontransfected cells (−). 48 h after transfection, cell lysates were analyzed by immunoblot with the N-terminal htt antibodies N18, 1C2, htt 55–66, htt 81–90, and htt 115–129. All antibodies, except htt 115–129, recognized the mhtt cleavage product (arrow) running approximately 10 kDa lower on SDS-PAGE than the main mhtt protein product. b The N-terminal fragment of htt-N171-18Q (approximately 18 kDa) migrates on SDS-PAGE in the same molecular range as the protein htt-N120-18Q detected on immunoblot with the antibody htt 81–90. c The protein htt-N120-82Q, the N-terminal cleavage fragment of htt-N233-82Q (arrow) and d of htt-FL-82Q from transfected HEK 293 cells have the same mobility on SDS-PAGE compared to the mhtt cleavage fragment from brain homogenate of HD N171-82Q line 81 transgenic (tg) mouse (lowest arrow) shown on immunoblot with the antibody htt 81–90