Movie 1.

Two-photon live imaging of neural tube closure in Ciona. Embryo co-electroporated with Msxb1.5kb>PH::mnG (membrane marker; green) and Sox1/2/3>H2B::mApp (nuclear marker; red). Time-lapse acquisition began at the early neurula stage (st. 14) and continued until the early tailbud stage (st. 19). The movie shows the posterior-to-anterior progression of the zipper during neural tube closure.