Gastrulation in an annual killifish: Molecular and cellular events during germ layer formation in Austrolebias.

Background: Comparative studies beyond the traditional model organisms have been instrumental in enhancing our understanding of the conserved and derived features of gastrulation, a fundamental process in which the germ layers are specified and shaped to form the body axis. Here, we analyzed gastrulation in a vertebrate group with an extreme mode of early development, the annual killifish.

Results: Gastrulation in annual killifish of the genus Austrolebias takes place after the initially dispersed deep blastomeres congregate to form the so-called reaggregate.

Close association of olfactory placode precursors and cranial neural crest cells does not predestine cell mixing.

Vertebrate sensory organs originate from both cranial neural crest cells (CNCCs) and placodes. Previously, we have shown that the olfactory placode (OP) forms from a large field of cells extending caudally to the premigratory neural crest domain, and that OPs form through cell movements and not cell division. Concurrent with OP formation, CNCCs migrate rostrally to populate the frontal mass.

The CK1 gene family: expression patterning in zebrafish development.

Protein kinase CK1 is a ser/thr protein kinase family which has been identified in the cytosol cell fraction, associated with membranes as well as in the nucleus. Several isoforms of this gene family have been described in various organisms: CK1alpha, CK1beta, CK1delta, CK1epsilon and CK1gamma. Over the last decade, several members of this family have been involved in development processes related to wnt and sonic hedgehog signalling pathways.