Specification of Drosophila neuropeptidergic neurons by the splicing component brr2
Fig 4
Axonal pathfinding and BMP pathway activation are affected in brr2 mutants.
(A-B) Expression of proFMRFa, ap-Gal4>UAS-GFP and buttonless-lacZ (btn>lacZ), in control and brr2 mutant (brr209c117) VNCs, at stage AFT (thoracic segments T1-T3). (A) In control, the six lateral Tv4 neurons project their axons (GFP- and proFMRFa-positive) into the three dorso-medial DNHs (btn>lacZ expressing; dashed circles). Box inset shows close-up on one DNH. (B) In brr2 mutants, the three DNHs are present, but Tv4 neurons fail to innervate the organ. (C-D) Transgenic expression of gbb in the Ap cluster of brr2 mutants (ap>gbb; brr209c117) fails to rescue proFMRFa and pMad (2–5 focal plane projections; stage AFT).