 This is why misexpression of Cerberus can cause the heart to fold in the opposite direction during development.When Cerberus is “knocked down” and BMP and Wnt are up regulated the head does not form.Other experiments using mice that this gene has been “knocked out” showed no head defects, which suggest that it is the combination of the up regulation of BMP and Wnt along with the absence of Cerberus that causes this defect.