Cell fate determination by ubiquitin-dependent regulation of translation

Metazoan development depends on accurate execution of differentiation programs that allow pluripotent stem cells to adopt specific fates. Differentiation is brought about by global changes to chromatin architecture and transcriptional networks, yet whether other regulatory events support cell fate determination is less well understood. Using human embryonic stem cell and Xenopus models, we identified the vertebrate-specific ubiquitin ligase Cul3KBTBD8 as an essential regulator of neural crest specification. Cul3KBTBD8 monoubiquitylates NOLC1 and its paralog TCOF1, whose mutation underlies the craniofacial disorder Treacher Collins Syndrome that is characterized by a loss of cranial neural crest cells. Ubiquitylation of NOLC1 and TCOF1 drives formation of a platform that connects RNA polymerase I with ribosome modification enzymes, thereby altering the translational program of differentiating cells to support the generation of neural crest cells. We conclude that the dynamic regulation of ribosome function is an important feature of cell fate determination. Overall design: Ribosome profiling and mRNA-Seq