Skip to main content
. 2020 Oct 30;9:e59650. doi: 10.7554/eLife.59650

Figure 5. The FMRFa BMP-LA motif has a necessary but low affinity Medea binding site that specifies selective neuronal subtype activity.

Figure 5.

(A–C) Conversion of the Medea-binding GTAT site in the wildtype 445 bp Tv4-neuron-specific FMRFa enhancer to a mutant version, ACTA (that reduces pMad/Medea recruitment; termed Tv4 mGTAT>ACTA–nEGFP), resulted in a complete loss of reporter gene expression in Tv4-neurons (B). Conversion of the Medea-binding GTAT site in the wildtype 445 bp Tv4-neuron-specific FMRFa enhancer to an optimal BMP-AE-like sequence (GACG; termed Tv4 mGTAT>GACG–nEGFP) also resulted in a total loss of reporter expression in Tv4-neurons (C). Numbers in insets indicate the mean ± SD number of EGFP-positive Tv4-neurons per VNC, out of the possible six Tv neurons. (D,E) The Tv4mGTAT>GACG–nEGFP reporter generated strong ectopic reporter activity in VNC midline cells (D) that is lost in the absence of neuronal BMP signaling (E; in wit mutants, witA12/witB11). Full z-projections though the whole VNC are shown. Numbers in insets indicate the mean ± SD number of EGFP-positive neurons per VNC. (D’–D’’’) Images of the midline ectopic EGFP expression generated from Tv4mGTAT>GACG–nEGFP. EGFP expression (green) was exclusively expressed in pMad-immunoreactive cells (magenta); all cells are yellow circled.