used for T7 polymerase-driven in vitro transcription reactions
(Promega). HA-DDX5 and FLAG-RORγt were in vitrotranscribed and translated using an in vitro transcription and translation (TNT)
system according to the manufacturer’s protocol (Promega).
Alternatively, pGEX4.1-DDX5 (wildtype and helicase-dead mutant) constructs were
transformed into BL21 to synthesize recombinant full-length GST-hDDX5 proteins.
Full-length His-tagged human RORγt was purified in three steps through
Ni-Resin, S column, and gel-filtration on AKTA. 0.5µg of each
recombinant protein was incubated in the presence or absence of 200 µM
ATP, 300ng in vitro transcribed Rmrp in coIP buffer containing
25mM Tris (pH 8.0), 100mM NaCl, 0.5% NP40, 10mM MgCl2, 10%
glycerol, 1X protease inhibitor, RNaseInhibitor (Invitrogen), and PhosphoSTOP
(Roche). GST-DDX5 was enriched on glutathione beads (GE), HA-DDX5,
FLAG-RORγt, and His-RORγt were enriched using anti-HA,
(Covance), anti-FLAG (Sigma), and anti-His antibodies (Santa Cruz Bio) coupled
to Anti-Mouse immunoglobulin Dynabeads (Dynal, Invitrogen).