Figure 4.

DDX3 activates AREG mRNA translation

(A) Schematic diagram showing humanized Renilla luciferase (hRL) reporters containing either or both of the 5′ and -3′ UTRs of AREG.

(B) In vivo translation assay using the indicated hRL reporters in siC- or siD#1-transfected SAS cells. The activity of human firefly luciferase (hFL) encoded by the same reporters was used as an internal control. Bar graph shows relative hRL/hFL activity (mean ± SD); ∗p < 0.01.

(C) Schematic diagram showing DDX3 in which two RecA-like domains are labeled in blue and violet and 11 conserved motifs (Q, I-VI), and the two mutations are indicated. An in vivo translation assay was performed using the indicated hRL reporters in endogenous DDX3-depleted (by siD#1) and exogenous DDX3 (wild-type or mutants)-overexpressing SAS cells. Bar graph shows relative hRL/hFL activity.

(D) SAS cells were transfected with siD#1 and the indicated DDX3 expression vectors. The lysates were analyzed by immunoblotting using antibodies as indicated.

(E) DDX3 modulates the translation of AREG mRNA via both its 5′ and -3′ UTR.