Opposing actions of histone deacetylase 1 and Notch signalling restrict expression of erm and fgf20a to hindbrain rhombomere centres during zebrafish neurogenesis

The rate and pattern of neurogenesis in the developing vertebrate nervous system is controlled by a complex interplay of intercellular signalling pathways and transcriptional control mechanisms. In the zebrafish hindbrain, Fgf20a promotes transcription of the gene encoding the ETS-domain transcription factor Erm in the non-neurogenic centres of rhombomeres. Here, we demonstrate that the epigenetic regulator, Histone Deacetylase 1 (Hdac1) and the Notch signalling pathway have opposing functions in regulating expression of both erm and fgf20a in the zebrafish hindbrain. Our results show that Hdac1 is required for expression of erm and fgf20a in rhombomeres, and that the Hdac1-dependent expression of these two genes is attenuated in rhombomere boundary regions by Notch signalling activity, thereby restricting erm and fgf20a transcripts to narrow stripes of cells at rhombomere centres.