Temporal dynamics of myelination in the zebrafish spinal cord.
Knowledge of the precise timing of myelination is critical to the success of zebrafish-based in vivo screening strategies for potential remyelination therapies. This study provides a systematic review of the timing of myelination in the zebrafish spinal cord and a critique of techniques by which it may be accurately assessed. The onset of myelination was found to be 3 days postfertilization (d.p.f.); earlier than previously reported. This coincided with the dorsal migration and differentiation of oligodendrocytes and the expression of myelin basic protein (Mbp) transcripts and protein. Our data suggests that immunohistochemistry with zebrafish-specific anti-Mbp from 3 d.p.f. is the optimal histological method for myelin visualization, while quantification of myelination is more reliably achieved by quantitative polymerase chain reaction (qPCR) for mbp from 5 d.p.f.. Transgenic fluorescent lines such as olig2:EGFP can be used to assess oligodendrocyte cell number at 3 d.p.f. and the development of new, more specific lines may enable real time visualization of myelin itself. Quantitative ultrastructural analysis revealed that the myelination of zebrafish axons is regulated according to axonal growth and not absolute axonal size. This study confirms the use of the zebrafish larvae as a versatile and efficient in vivo model of myelination and provides a platform on which future myelination screening studies can be based.
MRC Centre for Stem Cell Biology and Regenerative Medicine and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.
Clare E
CE
Buckley
Anita
A
Marguerie
Wendy K
WK
Alderton
Robin J M
RJ
Franklin
D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D049452:Green Fluorescent Proteins; D020439:Growth Cones / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D046529:Microscopy, Electron, Transmission; D023421:Models, Animal; D004676:Myelin Basic Protein / Q000235:genetics / Q000378:metabolism; D009413:Nerve Fibers, Myelinated / Q000378:metabolism* / Q000648:ultrastructure; D055495:Neurogenesis / Q000502:physiology; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D013997:Time Factors; D015027:Zebrafish / Q000196:embryology*
D004676:Myelin Basic Protein; D012333:RNA, Messenger; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins