Specific Drosophila Dscam juxtamembrane variants control dendritic elaboration and axonal arborization.
Drosophila Dscam isoforms are derived from two alternative transmembrane/juxtamembrane domains (TMs) in addition to thousands of ectodomain variants. Using a microRNA-based RNA interference technology, we selectively knocked down different subsets of Dscams containing either the exon 17.1- or exon 17.2-encoding TM. Eliminating Dscam[TM1] reduced Dscam expression but minimally affected postembryonic axonal morphogenesis. In contrast, depleting Dscam[TM2] blocked axon arborization. Further removal of Dscam[TM1] enhanced the loss-of-Dscam[TM2] axonal phenotypes. However, Dscam[TM1] primarily regulates dendritic development, as evidenced by the observations that removing Dscam[TM1] alone impeded elaboration of dendrites and that transgenic Dscam[TM1], but not Dscam[TM2], effectively rescued Dscam mutant dendritic phenotypes in mosaic organisms. These distinct Dscam functions can be attributed to the juxtamembrane regions of TMs that govern dendritic versus axonal targeting of Dscam as well. Together, we suggest that specific Drosophila Dscam juxtamembrane variants control dendritic elaboration and axonal arborization.
Shi
Lei
L
Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Yu
Hung-Hsiang
HH
Yang
Jacob S
JS
Lee
Tzumin
T
D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology*; D015815:Cell Adhesion Molecules; D003712:Dendrites / Q000502:physiology*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D014644:Genetic Variation / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009024:Morphogenesis / Q000235:genetics; D019006:Neural Cell Adhesion Molecules / Q000235:genetics / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology
D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; C491736:Dscam1 protein, Drosophila; D008565:Membrane Proteins; D019006:Neural Cell Adhesion Molecules; D020033:Protein Isoforms