DLK protein is stabilized in response to trophic factor withdrawal in embryonic sensory neurons. (A) Measurement of relative amount of Dlk transcript by real-time qRT-PCR in −NGF vs. +NGF culture conditions. n = 3 technical replicates. Error bar represents SD. −NGF vs. +NGF: 1.036 ± 0.0234. (B) 8-h time course of trophic factor withdrawal in −NGF-treated DRGs and +NGF controls in the presence of 5 µM cycloheximide. (C) Quantification of three repeated trials of experiment performed in B. Plotted is the relative amount of DLK remaining at a given time compared with the amount at time 0. Error bars are SDs. Each time course was fit to a line in GraphPad Prism software. *, P = 0.0109 when comparing the slopes of the two lines with ANCOVA. (D) DRGs were treated with the given conditions for 3 h and lysed. OA, 200 nM okadaic acid. MG132 was used at 30 µM. Both OA and MG132 treatment resulted in an increase in DLK protein levels. MW (kD), molecular weight in kilodaltons.