Biology Reference
In-Depth Information
18
Cell Crawling, Cell Behaviour and
Biomechanics During Convergence
and Extension
Ray Keller
and
Lance Davidson
The morphogenic movements of convergence and extension (narrowing and
lengthening) of embryonic tissues play major roles in gastrulation, neurulation
and body axis formation in vertebrates, and also function in many other
morphogenic processes in both vertebrates and invertebrates. These move-
ments are driven by polarized cell behaviours that appear to pull cells between
one another along the mediolateral axis and thereby elongate or extend the
tissue. Here we discuss the biomechanical relationship between these polarized
cell behaviours and the patterns of cell intercalation, during the active, force-
producing convergence and extension movements occurring in early Xenopus
morphogenesis.
Introduction
A major unresolved issue in morphogenesis is how polarized cell motility
produces the active, orientated intercalation of cells that drives the
convergence and extension movements found throughout the morphogenesis
of metazoans. Convergence and extension refer to the coordinated narrowing
(convergence) and lengthening (extension) movements of tissues during
morphogenesis. Convergence and extension elongate the anterior-posterior
