The transcription factor Zfh1 is involved in the regulation of neuropeptide expression and growth of larval neuromuscular junctions in Drosophila melanogaster.

Different aspects of neural development are tightly regulated and the underlying mechanisms have to be transcriptionally well controlled. Here we present evidence that the transcription factor Zfh1, the Drosophila member of the conserved zfh1 gene family, is important for different steps of neuronal differentiation. First, we show that late larval expression of the neuropeptide FMRFamide is dependent on correct levels of Zfh1 and that this regulation is presumably direct via a conserved zfh1 homeodomain binding site in the FMRFamide enhancer. Using MARCM analysis we additionally examined the requirement for Zfh1 during embryonic and larval stages of motoneuron development. We could show that Zfh1 cell autonomously regulates motoneuronal outgrowth and larval growth of neuromuscular junctions (NMJs). In addition, we find that the growth of NMJs is dependent on the dosage of Zfh1, suggesting it to be a downstream effector of the known NMJ size regulating pathways.