PUBLICATION
Zebrafish topped is required for ventral motor axon guidance
- Authors
- Rodino-Klapac, L.R., and Beattie, C.E.
- ID
- ZDB-PUB-040826-8
- Date
- 2004
- Source
- Developmental Biology 273(2): 308-320 (Journal)
- Registered Authors
- Beattie, Christine
- Keywords
- Motoneurons; Genetic mosaics; Genetic interactions; Axial muscle; Axon guidance; Intermediate targets
- MeSH Terms
-
- Mosaicism
- Zebrafish Proteins/genetics*
- Zebrafish Proteins/physiology*
- Zebrafish/embryology*
- Zebrafish/genetics*
- Animals
- Motor Neurons/cytology*
- Motor Neurons/physiology
- Mutation
- Muscle Fibers, Fast-Twitch/cytology
- Muscle Fibers, Fast-Twitch/physiology
- Genes, Recessive
- Axons/physiology
- Genes, Lethal
- Efferent Pathways/cytology
- Efferent Pathways/embryology*
- PubMed
- 15328015 Full text @ Dev. Biol.
Citation
Rodino-Klapac, L.R., and Beattie, C.E. (2004) Zebrafish topped is required for ventral motor axon guidance. Developmental Biology. 273(2):308-320.
Abstract
Zebrafish primary motor axons extend along stereotyped pathways innervating distinct regions of the developing myotome. During development, these axons make stereotyped projections to ventral and dorsal myotome regions. Caudal primary motoneurons, CaPs, pioneer axon outgrowth along ventral myotomes; whereas, middle primary motoneurons, MiPs, extend axons along dorsal myotomes. Although the development and axon outgrowth of these motoneurons has been characterized, cues that determine whether axons will grow dorsally or ventrally have not been identified. The topped mutant was previously isolated in a genetic screen designed to uncover mutations that disrupt primary motor axon guidance. CaP axons in topped mutants fail to enter the ventral myotome at the proper time, stalling at the nascent horizontal myoseptum, which demarcates dorsal from ventral axial muscle. Later developing secondary motor nerves are also delayed in entering the ventral myotome whereas all other axons examined, including dorsally projecting MiP motor axons, are unaffected in topped mutants. Genetic mosaic analysis indicates that Topped function is non-cell autonomous for motoneurons, and when wild-type cells are transplanted into topped mutant embryos, ventromedial fast muscle are the only cell type able to rescue the CaP axon defect. These data suggest that Topped functions in the ventromedial fast muscle and is essential for motor axon outgrowth into the ventral myotome.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping