Video 2.
Life imaging of a PATJ mutant Drosophila embryo expressing DE-Cad–GFP. This video is related to Fig. 2 and recorded as Video 1. Anterior is in the lower left corner. The embryo shown is derived from PATJΔ1 germline clones, lacking the maternal and zygotic expression of PATJ. The video starts shortly after cellularization, showing a rather normal germband elongation and segmentation but an incomplete germband retraction with the posterior end of the germband ending at ∼20% embryonic length instead of 0% as in the wild-type embryos (compare with Video 1). Out of 39 PATJ mutant embryos investigated, eight exhibited defects in germband retraction and head development, five died early in development, and the rest developed normally.