of apoptosis at sites of morphogenetic tissue fusion may not necessarily indicate a functional role, but rather a secondary outcome. The next question is: why do cells die during fusion of embryonic epithelia? Our study of the spatio-temporal distribution of dying cells during mouse neurulation revealed apoptosis predominantly associated with three main events: bending and fusion of the neural ...

The morphogenesis of rhombomeres (neuromeres) caudal to the preotic sulcus during neurulation in rat embryos is described. A model is proposed to explain the development of the characteristic neuromeric sulci and interneuromeric gyri based on the cytoskeletal elements and the kinetic behaviour of the neural epithelium. Evidence obtained from a study of control, cytochalasin D-treated and colchi...

Pitx-1 is a member of the family of bicoid-related vertebrate homeobox genes; it was originally identified as a tissue-specific transcriptional regulator of the proopiomelacortin gene. Here we report on the embryonic expression of Xpitx-1, which is expressed in the anterior neural ridge and in the cement gland Anlage during late gastrulation/early neurulation. In tadpole stage embryos Xpitx-1 t...

We have cloned Xenopus orthologues of the Drosophila planar cell polarity (PCP) gene Prickle. Xenopus Prickle (XPk) is expressed in tissues at the dorsal midline during gastrulation and early neurulation. XPk is later expressed in a segmental pattern in the presomitic mesoderm and then in recently formed somites. XPk is also expressed in the tailbud, pronephric duct, retina, and the otic vesicl...