In response to predation, crabs can reflexively shed their limbs, and over the course of the molt cycle, regenerate a new one
Crabs have a reiterative ability to regenerate a limb primordium in response to reflexive limb loss (autotomy). The developmental transformation of the unorganized limb primordium (i.e. blastema) into a polarized limb differs mechanistically from both embryonic vertebrate limb morphogenesis and insect limb development during metamorphosis. The proliferative and morphogenetic events involved in the organization of the blastema, and how ecdysteroid signaling may influence regional specification in the regenerating limb, are unclear. We are in the process of looking at the limb bud transcriptome at various stages of regeneration using high throughput massively parallel sequencing (RNAseq); several assembly iterations of the limb bud transcriptome at different developmental stages searchable by keyword and BLAST are located here. Through hormone manipulation and hormone signaling ablation experiments (e.g RNA interference) we hope to learn more about the role of ecdysteroid signaling in this process.
The two figures on the left show cell proliferation (through a BrdU incorporation assay- fluorescing cells) and normal blastemal growth and development (H&E section). The figures on the right show blocked proliferation and abnormal development as a consequence of RNAi knockdown of the ecdysteroid receptor.
