Berndt, A.J., Othonos, K.M., Lian, T., Flibotte, S., Miao, M., Bhuiyan, S.A., Cho, R.Y., Fong, J.S., Hur, S.A., Pavlidis, P., Allan, D.W. (2020). A low affinity cis-regulatory BMP response element restricts target gene activation to subsets of Drosophila neurons. eLife 9(): e59650.
FlyBase ID
FBrf0247280
Publication Type
Research paper
Abstract
Retrograde BMP signaling and canonical pMad/Medea-mediated transcription regulate diverse target genes across subsets of Drosophila efferent neurons, to differentiate neuropeptidergic neurons and promote motor neuron terminal maturation. How a common BMP signal regulates diverse target genes across many neuronal subsets remains largely unresolved, although available evidence implicates subset-specific transcription factor codes rather than differences in BMP signaling. Here we examine the cis-regulatory mechanisms restricting BMP-induced FMRFa neuropeptide expression to Tv4-neurons. We find that pMad/Medea bind at an atypical, low affinity motif in the FMRFa enhancer. Converting this motif to high affinity caused ectopic enhancer activity and eliminated Tv4-neuron expression. In silico searches identified additional motif instances functional in other efferent neurons, implicating broader functions for this motif in BMP-dependent enhancer activity. Thus, differential interpretation of a common BMP signal, conferred by low affinity pMad/Medea binding motifs, can contribute to the specification of BMP target genes in efferent neuron subsets.
