RT Journal Article SR Electronic T1 Foxc1 establishes enhancer accessibility for craniofacial cartilage differentiation JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.10.15.340703 DO 10.1101/2020.10.15.340703 A1 Pengfei Xu A1 Haoze Vincent Yu A1 Kuo-Chang Tseng A1 Mackenzie Flath A1 Peter Fabian A1 Neil Segil A1 J. Gage Crump YR 2020 UL http://biorxiv.org/content/early/2020/10/15/2020.10.15.340703.abstract AB The specification of cartilage requires Sox9, a transcription factor with broad roles for organogenesis outside the skeletal system. How Sox9 gains selective access to cartilage-specific cis-regulatory regions during skeletal development had remained unclear. By analyzing chromatin accessibility during the differentiation of neural crest cells into chondrocytes of the zebrafish head, we find that cartilage-associated chromatin accessibility is dynamically established. Cartilage-associated regions that become accessible after neural crest migration are co-enriched for Sox9 and Fox transcription factor binding motifs. In zebrafish lacking Foxc1 paralogs, we find a global decrease in chromatin accessibility in chondrocytes, consistent with a later loss of dorsal facial cartilages. Zebrafish transgenesis assays confirm that many of these Foxc1-dependent elements function as enhancers with region- and stage-specific activity in facial cartilages. We propose that Foxc1-dependent chromatin accessibility helps directs the versatile Sox9 protein to a chondrogenic program in the face.HighlightsDynamic chromatin accessibility across facial cartilage developmentCo-enrichment of Fox- and Sox-binding motifs in accessible regionsFoxc1 establishes accessibility in a subset of facial cartilage enhancersModular activity of Foxc1-dependent cartilage enhancers in zebrafish