title: O-fucosylation of DLL3 is required for its function during somitogenesis.
abstract: Delta-like 3 (DLL3) is a member of the DSL family of Notch ligands in amniotes. In contrast to DLL1 and DLL4, the other Delta-like proteins in the mouse, DLL3 does not bind in trans to Notch and does not activate the receptor, but shows cis-interaction and cis-inhibitory properties on Notch signaling in vitro. Loss of the DSL protein DLL3 in the mouse results in severe somite patterning defects, which are virtually indistinguishable from the defects in mice that lack lunatic fringe (LFNG), a glycosyltransferase involved in modifying Notch signaling. Like LFNG, DLL3 is located within the trans-Golgi, however, its biochemical function is still unclear. Here, we show that i) both proteins interact, ii) epidermal growth factor like repeats 2 and 5 of DLL3 are O-fucosylated at consensus sites for POFUT1, and iii) further modified by FNG proteins in vitro. Embryos double homozygous for null mutations in Dll3 and Lfng are phenotypically indistinguishable from the single mutants supporting a potential common function. Mutation of the O-fucosylation sites in DLL3 does not disrupt the interaction of DLL3 with LFNG or full length Notch1or DLL1, and O-fucosylation-deficient DLL3 can still inhibit Notch in cis in vitro. However, in contrast to wild type DLL3, O-fucosylation-deficient DLL3 cannot compensate for the loss of endogenous DLL3 during somitogenesis in the embryo. Together our results suggest that the cis-inhibitory activity of DLL3 observed in cultured cells might not fully reflect its assumed essential physiological property, suggest that DLL3 and LFNG act together, and strongly supports that modification of DLL3 by O-linked fucose is essential for its function during somitogenesis.
authors: Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany.
authors: Katrin
authors: K
authors: Serth
authors: Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany.
authors: Karin
authors: K
authors: Schuster-Gossler
authors: Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Molecular Immunology, Marchioninistrasse 25, 81377, Munich, Germany.
authors: Elisabeth
authors: E
authors: Kremmer
authors: Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany.
authors: Birte
authors: B
authors: Hansen
authors: Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany.
authors: Britta
authors: B
authors: Marohn-Köhn
authors: Institut für Molekularbiologie OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, 30625, Hannover, Germany.
authors: Achim
authors: A
authors: Gossler
mesh_terms: D000818:Animals; D016466:CHO Cells; D002135:Calcium-Binding Proteins; D006224:Cricetinae; D003412:Cricetulus; D005643:Fucose / Q000378:metabolism*; D016695:Glycosyltransferases / Q000378:metabolism; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009024:Morphogenesis / Q000502:physiology*; D051880:Receptors, Notch / Q000378:metabolism; D019170:Somites / Q000196:embryology*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; C512925:Dlk1 protein, mouse; C511877:Dll3 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; D005643:Fucose; D016695:Glycosyltransferases; C498392:Lfng protein, mouse