Transmembrane ligand protein of NOTCH1, NOTCH2 and NOTCH3 receptors that binds the extracellular domain (ECD) of Notch receptor in a cis and trans fashion manner (PubMed:21985982, PubMed:10958687). Following transinteraction, ligand cells produce mechanical force that depends of a clathrin-mediated endocytosis, requiring ligand ubiquitination, EPN1 interaction, and actin polymerisation; these events promote Notch receptor extracellular domain (NECD) transendocytosis and triggers Notch signaling through induction of cleavage, hyperphosphorylation, and nuclear accumulation of the intracellular domain of Notch receptors (NICD) (PubMed:10958687, PubMed:18676613). Is required for embryonic development and maintenance of adult stem cells in many different tissues and immune systeme; the DLL1-induced Notch signaling is mediated through an intercellular communication that regulates cell lineage, cell specification, cell patterning and morphogenesis through effects on differentiation and proliferation (PubMed:17194759, PubMed:19562077, PubMed:18997111, PubMed:23695674, PubMed:16495313, PubMed:21238454, PubMed:22282195, PubMed:7671806, PubMed:17960184, PubMed:22529374, PubMed:19389377, PubMed:23699523, PubMed:19144989, PubMed:23688253, PubMed:23806616, PubMed:26114479, PubMed:22940113, PubMed:25220152, PubMed:20081190, PubMed:21572390, PubMed:22096075). Plays a role in brain development at different level, namely by regulating neuronal differentiation of neural precursor cells via cell-cell interaction, most likely through the lateral inhibitory system in an endogenous level dependent-manner (PubMed:7671806, PubMed:18997111). During neocortex development, Dll1-Notch signaling transmission is mediated by dynamic interactions between intermediate neurogenic progenitors and radial glia; the cell-cell interactions are mediated via dynamic and transient elongation processes, likely to reactivate/maintain Notch activity in neighboring progenitors, and coordinate progenitor cell division and differentiation across radial and zonal boundaries (PubMed:23699523). During cerebellar development, regulates Bergmann glial monolayer formation and its morphological maturation through a Notch signaling pathway (PubMed:23688253). At the retina and spinal cord level, regulates neurogenesis by preventing the premature differentiation of neural progenitors and also by maintaining progenitors in spinal cord through Notch signaling pathway (PubMed:19389377, PubMed:26114479). Also controls neurogenesis of the neural tube in a progenitor domain-specific fashion along the dorsoventral axis (PubMed:20081190). Maintains quiescence of neural stem cells and plays a role as a fate determinant that segregates asymmetrically to one daughter cell during neural stem cells mitosis, resulting in neuronal differentiation in Dll1-inheriting cell (PubMed:23695674). Plays a role in immune systeme development, namely the development of all T-cells and marginal zone (MZ) B cells (PubMed:15146182, PubMed:19217325). Blocks the differentiation of progenitor cells into the B-cell lineage while promoting the emergence of a population of cells with the characteristics of a T-cell/NK-cell precursor (By similarity). Upon MMP14 cleavage, negatively regulates Notch signaling in haematopoietic progenitor cells to specifically maintain normal B-cell development in bone marrow (PubMed:21572390). Also plays a role during muscle development. During early development, inhibits myoblasts differentiation from the medial dermomyotomal lip and later regulates progenitor cell differentiation (PubMed:17194759). Directly modulates cell adhesion and basal lamina formation in satellite cells through Notch signaling. Maintains myogenic progenitors pool by suppressing differentiation through down-regulation of MYOD1 and is required for satellite cell homing and PAX7 expression (PubMed:22940113). During craniofacial and trunk myogenesis suppresses differentiation of cranial mesoderm-derived and somite-derived muscle via MYOD1 regulation but in cranial mesoderm-derived progenitors, is neither required for satellite cell homing nor for PAX7 expression (PubMed:25220152). Also plays a role during pancreatic cell development. During type B pancreatic cell development, may be involved in the initiation of proximodistal patterning in the early pancreatic epithelium (PubMed:22529374). Stimulates multipotent pancreatic progenitor cells proliferation and pancreatic growth by maintaining HES1 expression and PTF1A protein levels (PubMed:22096075). During fetal stages of development, is required to maintain arterial identity and the responsiveness of arterial endothelial cells for VEGFA through regulation of KDR activation and NRP1 expression (PubMed:19144989). Controls sprouting angiogenesis and subsequent vertical branch formation througth regulation on tip cell differentiation (PubMed:22282195). Negatively regulates goblet cell differentiation in intestine and controls secretory fat commitment through lateral inhibition in small intestine (PubMed:21238454, PubMed:21915337). Plays a role during inner ear development; negatively regulates auditory hair cell differentiation (PubMed:16495313). Plays a role during nephron development through Notch signaling pathway (PubMed:23806616). Regulates growth, blood pressure and energy homeostasis (PubMed:19562077). Homodimer (PubMed:12794186). Interacts with TJP1 (PubMed:24715457). Interacts with MMP14; inhibits DLL1-induced Notch signaling (PubMed:21572390). Interacts with MAGI1 (via PDZ domain); forms a complex with CTNNB1 and CDH2 and promotes recruitment to the adherens junction and stabilization on the cell surface (PubMed:15908431). Interacts with PSEN1; undergoes a presenilin-dependent gamma-secretase cleavage that releases a Dll1-intracellular form (PubMed:12794186). Interacts with MFAP5 (PubMed:15788413). Interacts with MIB1 (PubMed:21985982). Interacts with NEURL1B; leads to ubiquitination (PubMed:17003037, PubMed:19723503). Interacts with NEURL1 (PubMed:19723503). Interacts with SYNJ2BP; enhances DLL1 protein stability, and promotes Notch signaling in endothelial cells (By similarity). Interacts with MAGI1, MAGI2, MAGI3 and MPDZ (By similarity). Interacts (via ubiquitin) with EPN1 (via IUM domain); binding with NOTCH1 attached to neighboring cell, promotes ligand ubiquitination and EPN1 interaction, leading to NECD transendocytosis and Notch signaling. Interacts with NOTCH1 (By similarity). Distributed around adherens junction in the apical endfeet through interactions with MAGI1. In the embryo, expressed in the paraxial mesoderm and nervous system. Expressed at high levels in adult heart and at lower levels, in adult lung. Highly expressed in satellite cells from masseter and tongue than in satellite cells from leg and extraocular muscle.? (PubMed:25220152). Expressed until 15 dpc. Expression then decreases and increases again in the adult. In differentiating somites, is expressed at low levels in cells emerging from the dorsomedial lip and subsequently throughout myotomes. In the limb buds, is found in myoblasts and myocytes but not in the progenitor cells (PubMed:17194759). Highly expressed in the endothelium and in the smooth muscle layer starting at 13.5 dpc in arterial vessels, but not in veins. At 12.5 dpc, there is no detectable expression in arteries or veins. This pattern persists until 18.5 dpc (PubMed:19144989). Strongly expressed in developing muscle of tongue, cheek, and in extraocular muscle at 11.5 dpc. Found at 18 dpc and P21 in head muscle (PubMed:25220152). Detected in a subset of cells in the ventricular zone (VZ), the intermediate zone (IZ) and the cortical plate (CP) of neocortex and in the ganglionic eminences at 13.5 dpc. At later stages, such as at 16.5 dpc, found in the VZ and IZ, but at very low levels in the CP of the neocortex (PubMed:18997111). Highly expressed in embryonic cells located in the ventricular zone (VZ) of the retinal neuroepithelium that form clusters; is first detected in cells located in the central retina. As the retina grows, expression spreads peripherally along the expanding neurogenic region, being always absent from the ciliary margin zone (CMZ) (PubMed:19389377). Induced by PTF1A in multipotent pancreatic progenitor cells (PubMed:22096075). Induced by CDX1 and CDX2 during somitogenesis and goblet cell differentiation (PubMed:22015720). Ubiquitinated by MIB (MIB1 or MIB2), leading to its endocytosis and subsequent degradation. Ubiquitinated; promotes recycling back to the plasma membrane and confers a strong affinity for NOTCH1 (PubMed:18676613). Multi-ubiquitination of LYS-613 by MIB1 promotes both cis and trans-interaction with NOTCH1, as well as activation of Notch signaling (PubMed:21985982). Ubiquitinated by NEURL1B (PubMed:17003037). Phosphorylated in a membrane association-dependent manner. Phosphorylation at Ser-696 requires the presence of Ser-693, whereas phosphorylation at Thr-638 and Ser-693 occurs independently of the other sites. Phosphorylation is required for full ligand activity in vitro and affects surface presentation, ectodomain shedding, and endocytosis. Cleaved by MMP14; negatively regulates DLL1-induced Notch signaling in HPCs, modulating B-lymphocyte differentiation in bone marrow (PubMed:21572390). Undergoes two consecutive processing events: a shedding event, partially by ADAM10, that generates a soluble extracellular form and an intracellular membrane-anchored form, followed by a gamma-secretase cleavage releasing an intracellular fragment (PubMed:12794186). O-fucosylated. Can be elongated to a disaccharide by MFNG. Heterozygous Dll1 mice mutants are lighter and smaller, with altered fat to lean ratio and have increased blood pressure and a slight bradycardia. The animals have reduced cholesterol and triglyceride levels in blood (PubMed:19562077). Heterozygous Dll1 mice mutants and hypomorphic Dll1 mice mutants survive until birth, despite significantly reduced Notch activity (PubMed:17194759). Conditional knockout in inner ear leads to an early and excessive production of hair cells and have vestibular defects (PubMed:16495313). Conditional knockout in a small proportion of neural precursor cells reduces neurogenesis, whereas conditional knockout in a large proportion promotes premature neurogenesis (PubMed:18997111). Hypomorph Dll1 pups mutant survive until birth but are smaller. Conditional knockout Dll1 mice mutant in epidermis, survive and have no gross abnormalities (PubMed:17960184). Hypomorph Dll1 mice mutant survive until birth and have severe skeletal muscle defects (PubMed:19144989). Heterozygous Dll1 mutant embryos show disrupted muscle growth (PubMed:25220152). Conditional knockout Dll1 mice mutant show disorganization of Bergmann fibers, ectopic localization of Bergmann glia in the molecular layer and a reduction in the number of Bergmann glia (PubMed:23688253).