Sox10ER^T2CreER^T2 mice enable tracing of distinct neural crest cell populations

Background:: Neural crest cells play an important role in craniofacial morphogenesis and many other developmental processes. The formation of neural crest cells (NCCs) in vivo is a highly dynamic process and remains to be fully understood. Results:: To investigate the spatiotemporal patterning of NCCs in vivo, we have generated Sox10ER^T2CreER^T2 (SECE) mice, a transgenic line driving inducible Cre expression in NCCs. Inducing Cre activity at different stages triggered reporter expression in distinct NCC populations in SECE; R26R mice. By optimizing the timing and dosage of tamoxifen administration, we controlled Cre expression specifically in cranial NCCs. Using this approach, we demonstrate an important role for PDGFRα in cranial NCCs mitosis within the mandibular processes. Further reducing Cre activity within the cranial NCCs of SECE; R26R embryos revealed that SECE labels preferentially progenitors of medial nasal process (MNP) rather than the lateral nasal process (LNP), before their formation from the frontonasal prominence (FNP). Conclusions:: Our results indicate that NCCs are formed sequentially from rostral to caudal regions along the neural tube. These findings also suggest that NCCs within the FNP become specified regionally and genetically before they divide into MNP and LNP.