Researchers in the College of Life Sciences investigating how our bodies are generated during embryonic development have uncovered critical signaling events that determine vertebrate body length.
The work reported in the leading Open Access journal, PLoS Biology, reveals that body length depends on the activity of a key signal Fibroblast Growth Factor (FGF), which maintains an important cell group known as axial stem cells. These special cells are found at the tail end of the embryo and progressively give rise to the tissues of the body, including muscle, backbone and spinal cord.
Researchers in Kate Storey’s laboratory in the Division of Cell & Developmental Biology, identified these cells using molecular markers and by manipulating FGF signaling specially in the tailbud demonstrated that they are maintained by this signal. They further showed that increasing activity of the vitamin A derivative, retinoic acid, in the tailbud inhibits FGF, and that this leads to loss of the axial stem cell state. Opposition of these two signaling pathways occurs in other parts of our bodies, such the limb, raising the possibility that a similar signaling mechanism controls the dimensions of further key elements of our body plan.
Olivera-Martinez I, Harada H, Halley PA, Storey KG (2012) Loss of FGF-Dependent Mesoderm Identity and Rise of Endogenous Retinoid Signalling Determine Cessation of Body Axis Elongation. PLoS Biol 10(10): e1001415. doi:10.1371/journal.pbio.1001415
Image: FGF8 gene expression (blue) at the tail tip and at the leading edge of expanding limb bud (as well as in forming muscle blocks in the body).