As indicated in Fig 1, immunodetection of glutamylated tubulin (Glut-Tub, Fig 1A ) and acetylated-tubulin (Ace-Tub, Fig 1B ) show solitary rod-like structures that project 1 μm away from the OPC cell body which, when assayed by double immunofluorescence, display also γ-tubulin staining at their cell-proximal end (Fig 1, merged images and projection in S1 Video ).