Given that DDX3 interacts with HCV core and NS5A16, 17, 18, 34 and is down-regulated by HCV infection (Fig. 1a), HCV infection may interfere with the DDX3-augmented transactivation activity of HNF4 on MTP promoter leading to reduced MTP expression by which, at least in part, HCV infection induces liver steatosis. This evidence concerns the gene MTTP and fatty liver disease.