Genetic analysis of Netrin genes in Drosophila: Netrins guide CNS commissural axons and peripheral motor axons.
Two tandem Netrin genes in Drosophila are expressed at the midline of the developing CNS and in different subsets of neurons, muscles, and epidermal patches. In embryos carrying a small deficiency that deletes both genes, CNS axon commissures are partially missing or thinner. This phenotype is rescued by expressing either Netrin gene at the midline. Pan-neural expression of either gene causes disruption of commissural and longitudinal tracts, indicating that the pattern of Netrin expression is crucial and that Netrins function as instructive cues. The double mutant also shows defects in motor axon projections. Expression of either Netrin gene in all muscles also results in aberrant motor projections. Thus, Drosophila Netrins are required for the guidance of commissural axons at the midline, and of motor axons to their target muscles.
Mitchell
K J
KJ
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley California 94720, USA.
Doyle
J L
JL
Serafini
T
T
Kennedy
T E
TE
Tessier-Lavigne
M
M
Goodman
C S
CS
Dickson
B J
BJ
D000818:Animals; D001369:Axons / Q000502:physiology*; D001483:Base Sequence; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology / Q000502:physiology; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004330:Drosophila / Q000235:genetics*; D004817:Epidermis / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000502:physiology* / Q000648:ultrastructure; D009132:Muscles / Q000502:physiology; D009414:Nerve Growth Factors / Q000235:genetics*; D000075388:Netrin-1; D000075385:Netrins; D016501:Neurites / Q000502:physiology; D017933:Peripheral Nervous System / Q000166:cytology / Q000196:embryology / Q000502:physiology; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D025521:Tumor Suppressor Proteins
D009414:Nerve Growth Factors; D000075385:Netrins; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1; C088894:netrin-2