Sox8 reprogram ectoderm into ear vesicles and auditory neurons [smartseq2]

The vertebrate inner ear arises from a pool of progenitors with the potential to give rise to all the sense organs and cranial ganglia of the head1-6. Here we explore the molecular mechanisms that control ear specification from these progenitors. Using a multi-omics approach combined with loss-of-function experiments we identify a core transcriptional circuit that imparts ear identity, along with non-coding elements that integrate this information. This analysis places the transcription factor Sox8 at the top of the ear determination network. Introducing Sox8 into cranial ectoderm not only converts non-ear cells into ear progenitors, but also activates the cellular programmes for ear morphogenesis and neurogenesis. Thus, Sox8 emerges as a master regulator of ear identity and may be a key factor for sense organ cell reprogramming. Chick embryos were electroporated at head fold stages with Pax2E1-EGFP reporter constructs. Embryos were grown at 38°C until the desired somite stages (ss8-9, ss11-12, ss14-15). Heads were cut rostral to the first somite and processed for dissociation. EGFP+ single cells were collected by FACS into 96 well plates containing 2.3ul of lysis buffer. Single cell RNA libraries were generated and submitted for PE 75bp sequencing with the HiSeq4000.