Figure 1. Western blot analysis of Cdk7 using anti-Cdk7 antibody (PB9536). Electrophoresis was performed on a 5-20% SDS-PAGE gel at 70V (Stacking gel) / 90V (Resolving gel) for 2-3 hours. Lane 1: MCF-7 Whole Cell Lysate at 40ug, Lane 2: HELA Whole Cell Lysate at 40ug, Lane 3: A549 Whole Cell Lysate at 40ug, Lane 4: HEPG2 Whole Cell Lysate at 40ug, Lane 5: 293T Whole Cell Lysate at 40ug. After electrophoresis, proteins were transferred to a nitrocellulose membrane at 150 mA for 50-90 minutes. Blocked the membrane with 5% non-fat milk/TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-Cdk7 antigen affinity purified polyclonal antibody (Catalog # PB9536) at 0.5 microg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an Enhanced Chemiluminescent detection (ECL) kit (Catalog # EK1002) with Tanon 5200 system. A specific band was detected for Cdk7 at approximately 39 kDa. The expected band size for Cdk7 is at 39 kDa.