Defining the role of RA in craniofacial musculoskeletal patterning - contact PD/PI: segura, alia project summary retinoic acid (RA) is a key signaling pathway that has various roles across embryonic…

Defining the role of RA in craniofacial musculoskeletal patterning - contact PD/PI: segura, alia project summary retinoic acid (RA) is a key signaling pathway that has various roles across embryonic development. RA embryopathies encompass a multitude of birth defects resulting from an excess or lack of maternal diet-derived RA. Craniofacial malformations have been identified as a phenotype of a loss of function of CYP26 and aldh family members, required in degrading and synthesizing RA, respectively. Our lab has identified malformations in muscle and tendons of the lower jaw in zebrafish resulting from a mutation in CYP26B1. Studying craniofacial malformations as a result of teratogenic and suboptimal doses of RA requires attention as a loss of RA synthesizing and catabolizing genes have demonstrated clinical relevance with hearing loss and craniofacial defects identified in patients carrying variant alleles in CYP26B1. I want to understand the role RA plays in tendon condensation and subsequent muscle elongation in the lower jaw. I hypothesize that RA is produced by tenocytes and required for multiple tissues in the lower jaw in regulating cell guidance and adhesion programs to permit proper musculoskeletal integration. Here, I will utilize zebrafish to model the craniofacial defects brought on by disrupted RA signaling. I aim to identify the CYP26, aldh and RA receptors that are present at the time of tendon condensation and how their absence affects tenocyte behavior using fluorescent in situ hybridization and crispr-knockout strategies. I also aim to look upstream of tendon condensation and determine the transcription factors required for establishing the RA system in the lower jaw using linage tracing studies and transgenic signaling pathway readouts. Next, I aim to understand how RA is influencing tenocytes at the transcriptomic and translation levels. Here, I will use single- cell RNA-SEQ approaches, and ribosome profiling to study RA's gene regulatory mechanisms. My proposed work will allow US to understand the extent of RA in forming musculoskeletal attachments in the lower jaw and how disruptions in RA signaling leads to craniofacial defects. Project summary