Fig. 1

The expression of mbpa isoforms is developmental- and tissue-specific. (A) Schematic illustration of the mbpa isoforms reported in the Ensembl database (release 90). The numbers to the left indicate the identity of the isoform, the numbers above each isoform indicate the position of the first nucleotide in the coding sequence and the 3’UTR, respectively, and the numbers to the right indicate the total reported length. Note that the reported sequences are not complete at the 3’ends. (B) RNA was purified from zebrafish larvae at the indicated hours post fertilization (hpf), and from adult brain (central nervous system, CNS) or lateral line peripheral nervous system (PNS). RT-PCR was performed with equal amounts of RNA as template with a primer set annealing to exon-1 and -6. Primers amplifying β-actin was included as control. The most prominent DNA bands from the CNS and PNS were sequenced and identified as variants 207 and 211, respectively. (C) Whole-mount in situ hybridization (WISH) was performed on zebrafish larvae at 96 hpf with probes annealing to different positions of the mbpa mRNA, as indicated. The probes annealing to exon-1 (mbpa all isoforms) and exon-6 (mbpa +3’UTR) gave similar results, with a distinct signal in the hindbrain and spinal cord of the CNS (white arrows), and in the posterior (black arrows) and anterior (black arrowheads) lateral line system. The probe annealing to exon-4–5 (mbpa Exon 4 + 5) resulted in a signal in the posterior (black arrows) and anterior (black arrowheads) lateral line system, however, the signal observed in the CNS with the other two probes was completely absent. Images are representative of several larvae from two independent experiments.