Current research on mechanisms of limb bud development; future difficulties to face over the coming 10 years

Abstract

The developmental mechanisms of limb buds have been studied in developmental biology as a great model of pattern formation. Chick embryos have contributed to the discovery of new principles in developmental biology, as it is easy to observe live embryos and manipulate embryonic tissues. Herein, we outline the current findings and future issues over the next 10 years regarding three themes, based on our research: 1) limb positioning, 2) proximal-distal limb elongation, and 3) digit identity determination. First, how hindlimb position is determined at the molecular level is described in the focus of transforming growth factor-β(TGF-β) signaling molecule, GDF11. Second, we explain how the cell population in the limb bud deforms with developmental progress shaping the limb bud with elongation along the proximal-distal axis. Finally, we describe the developmental mechanisms that determine digit identity through the interdigits.