Robustness in the feedback control of the retinoic acid network response to environmental disturbances (BioMark-qRT-PCR)

Retinoic acid (RA) is a central developmental signal whose perturbation results in teratogenic outcomes. RA is tightly regulated during early embryonic development to achieve fine-tuning of the instructive and permissive signals regulating multiple developmental processes including head formation. We aim to identify the key mechanisms underlying the homeostatic regulation and tuning of the retinoic acid signaling levels, the disruption of which in the head lead to wide ranging developmental malformations including microcephaly and other craniofacial defects. We performed transient physiological RA signaling disturbances during Xenopus laevis embryogenesis followed by kinetic gene expression analysis of the recovery at multiple time points. We considered multiple experimental perturbations including exogenous addition of 10 nM RA, inhibition of RA production by 50 uM DEAB (an inhibitor of RALDH2 enzyme) and no exposure control. We obtained data from six independent clutches for each experimental condition. The embryos were isolated at multiple time points (t=0, 1.5, 3, and 4.5 hours) following two hours of perturbation and a wash.