Analysis of Proteolytic Processes and Enzymatic Activities in the Generation of Huntingtin N-Terminal Fragments in an HEK293 Cell Model
A, HEK293 cells were non-transfected (NTf) or transfected with cDNA encoding htt N171-18Q. Cell lysates were analyzed by immunoblots incubated with antibodies 2B4 or 1H6. B, HEK293 cells were transfected with htt cDNAs shown at the top of the figure, followed by lysis and SDS-PAGE. Arrowheads identify substrates or cleavage products that are generated at approximately equally levels for short and expanded polyglutamine lengths. The lack of an effect of polyglutamine length on cleavage efficiency was observed for both N171 and N586 based constructs. Immunoblots were probed with the htt81-90 antibody (1∶3000). The images shown are representative of at least 3 repetitions of the experiment. EH = endogenous htt.