Fig. 2

mbpb expression is similar, but not identical to mbpa expression. (A) Schematic representation of the isoforms reported in the Ensembl database (release 90) originating from two different transcription start sites in the golli/mbpb gene unit. 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. Isoforms 205 and 202 encode the Golli protein, while the isoforms 203 and 201 encode Mbpb. (B) RNA was purified from zebrafish larvae at the indicated hours post fertilization, and from the adult brain (CNS) or lateral line (PNS). RT-PCR was performed with equal amounts of RNA as template with primers recognizing either mbpb or golli mRNA. A primer set for β-actin was included as a control. (C) WISH performed on zebrafish larvae at 96 hpf with a probe specific for mbpb mRNA resulted in a robust signal in the hindbrain and ventral spinal cord (white arrows), and posterior (black arrow) and anterior (white arrowhead) lateral line system. Furthermore, mbpb mRNA was detected in a symmetrical pattern in the dorsolateral spinal cord (black arrowheads). Note the presence of mbpb mRNA in the myelin sheaths covering the fine axons travelling laterally from the midline in the hindbrain, best visible in the dorsal view of the head region. Images are representative of two individual experiments with at least 15 larvae examined for each WISH probe in each experiment.