FIG. 6.

CDO enhances the activity of Ngn1 and its heterodimerization with E proteins. (A) Ngn1-specific reporter gene activity. C17.2 cells were cotransfected in growth medium with an Ngn-responsive luciferase reporter construct and the indicated combinations of expression vectors for Ngn1, E12, and CDO. The luciferase activity was assessed 48 h after transfection and normalized to an internal control reporter (Renilla luciferase). Activity is reported as fold stimulation above that obtained with cells transfected with the reporter plasmid but only control vectors lacking cDNA. Values are means of triplicate determinations performed four independent times. (B) Coimmunoprecipitation of Ngn1(myc) and E47 in C17.2 neural progenitors and 10T1/2 cells. Cells were cotransfected with the indicated combinations of expression vectors for Ngn1 and CDO. Twenty-four hours later, cells were shifted to DM and cultured further for 24 h. Cells were lysed and lysates were subjected to coimmunoprecipitation with antibody to the endogenous E47 protein. Immunoprecipitations were Western blotted for Ngn1(myc), E47, and CDO expression.