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Chad A. Dickey, Adeela Kamal, Karen Lundgren, Natalia Klosak, Rachel M. Bailey, Judith Dunmore, Peter Ash, Sareh Shoraka, Jelena Zlatkovic, Christopher B. Eckman, Cam Patterson, Dennis W. Dickson, N. Stanley Nahman, Michael Hutton, Francis Burrows, Leonard Petrucelli
Published in Volume 117, Issue 3
J Clin Invest. 2007; 117(3):648–658 doi:10.1172/JCI29715
Abstract | Full text | PDF | Supplemental material
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Figure 3
Targeted knockdown of primary components of the chaperone pathway promotes robust and rapid reductions in protein levels.

(A) HeLa cells were transfected in duplicate with a scrambled nonsilencing siRNA control or 2 independent siRNAs per gene, targeting the indicated components of the chaperone cycle. After 72 hours, the cells were treated with EC102 (1 μM) for an additional 24 hours and harvested for Western analyses. Knockdown efficiency at the protein level for both siRNAs targeting 7 of the 8 genes was greater than 60% and averaged 80%. Only siRNAs targeting Hsp70 had modest reductions of approximately 30%. Induction of Hsps by EC102 was also prevented by their knockdown, with the exception of Hsp70. GAPDH immunoreactivity was assessed on each membrane to control for loading differences. The panel shown is representative for all membranes. Based on similar knockdown efficiencies, these siRNAs were pooled for subsequent studies. Quantitation was assessed by densitometry. (B) HeLa cells were transfected with either nonsilencing siRNA control or 2 siRNA pools targeting Hsp90 or HSF1. The cells were harvested at the indicated time points. Partial knockdown was apparent after 24 hours for both genes, and immunoreactivity decreased further with each additional 24-hour interval. The 72-hour time point was chosen for subsequent studies to avoid issues associated with toxicity.