The Abruptex domain of Notch regulates negative interactions between Notch, its ligands and Fringe

Development ◽  
2000 ◽  
Vol 127 (6) ◽  
pp. 1291-1302 ◽  
Author(s):  
J.F. de Celis ◽  
S.J. Bray
Keyword(s):  
Cell Fate ◽  
Extracellular Domain ◽  
Wing Disc ◽  
Missense Mutations ◽  
Negative Effects ◽  
Notch Signalling Pathway ◽  
Notch Activity ◽  
Notch Protein ◽  
Invertebrate Development ◽  
Dorsoventral Boundary

The Notch signalling pathway regulates cell fate choices during both vertebrate and invertebrate development. In the Drosophila wing disc, the activation of Notch by its ligands Delta and Serrate is required to make the dorsoventral boundary, where several genes, such as wingless and cut, are expressed in a 2- to 4-cell-wide domain. The interactions between Notch and its ligands are modulated by Fringe via a mechanism that may involve post-transcriptional modifications of Notch. The ligands themselves also help to restrict Notch activity to the dorsoventral boundary cells, because they antagonise the activation of the receptor in the cells where their expression is high. This function of the ligands is critical to establish the polarity of signalling, but very little is known about the mechanisms involved in the interactions between Notch and its ligands that result in suppression of Notch activity. The extracellular domain of Notch contains an array of 36 EGF repeats, two of which, repeats 11 and 12, are necessary for direct interactions between Notch with Delta and Serrate. We investigate here the function of a region of the Notch extracellular domain where several missense mutations, called Abruptex, are localised. These Notch alleles are characterised by phenotypes opposite to the loss of Notch function and also by complex complementation patterns. We find that, in Abruptex mutant discs, only the negative effects of the ligands and Fringe are affected, resulting in the failure to restrict the expression of cut and wingless to the dorsoventral boundary. We suggest that Abruptex alleles identify a domain in the Notch protein that mediates the interactions between Notch, its ligands and Fringe that result in suppression of Notch activity.

Structural requirements for notch signalling with delta and serrate during the development and patterning of the wing disc of Drosophila

Development ◽  
2000 ◽  
Vol 127 (14) ◽  
pp. 3185-3195 ◽  
Author(s):  
N. Lawrence ◽  
T. Klein ◽  
K. Brennan ◽  
A. Martinez Arias
Keyword(s):  
Function Analysis ◽  
Extracellular Domain ◽  
Wing Disc ◽  
Notch Signalling ◽  
Notch Receptor ◽  
Wing Development ◽  
Ankyrin Repeats ◽  
Loss Of Function ◽  
Structural Requirements ◽  
Notch Protein

The delta and Serrate proteins interact with the extracellular domain of the Notch receptor and initiate signalling through the receptor. The two ligands are very similar in structure and have been shown to be interchangeable experimentally; however, loss of function analysis indicates that they have different functions during development and analysis of their signalling during wing development indicates that the Fringe protein can discriminate between the two ligands. This raises the possibility that the signalling of delta and Serrate through Notch requires different domains of the Notch protein. Here we have tested this possibility by examining the ability of delta and Serrate to interact and signal with Notch molecules in which different domains had been deleted. This analysis has shown that EGF-like repeats 11 and 12, the RAM-23 and cdc10/ankyrin repeats and the region C-terminal to the cdc10/ankyrin repeats of Notch are necessary for both delta and Serrate to signal via Notch. They also indicate, however, that delta and Serrate utilise EGF-like repeats 24–26 of Notch for signalling, but there are significant differences in the way they utilise these repeats.

Immobilization of Notch ligand, Delta-1, is required for induction of notch signaling

2000 ◽  
Vol 113 (23) ◽  
pp. 4313-4318 ◽  
Author(s):  
B. Varnum-Finney ◽  
L. Wu ◽  
M. Yu ◽  
C. Brashem-Stein ◽  
S. Staats ◽  
...  
Keyword(s):  
Cell Fate ◽  
Extracellular Domain ◽  
Notch Ligand ◽  
Cell Fate Decisions ◽  
Plastic Surface ◽  
Ligand Stabilization ◽  
Potential Activity ◽  
Inhibition Of Differentiation ◽  
Notch Ligands ◽  
Notch Activation

Cell-cell interactions mediated by Notch and its ligands are known to effect many cell fate decisions in both invertebrates and vertebrates. However, the mechanisms involved in ligand induced Notch activation are unknown. Recently it was shown that, in at least some cases, endocytosis of the extracellular domain of Notch and ligand by the signaling cell is required for signal induction in the receptive cell. These results imply that soluble ligands (ligand extracellular domains) although capable of binding Notch would be unlikely to activate it. To test the potential activity of soluble Notch ligands, we generated monomeric and dimeric forms of the Notch ligand Delta-1 by fusing the extracellular domain to either a series of myc epitopes (Delta-1(ext-myc)) or to the Fc portion of human IgG-1 (Delta-1(ext-IgG)), respectively. Notch activation, assayed by inhibition of differentiation in C2 myoblasts and by HES1 transactivation in U20S cells, occurred when either Delta-1(ext-myc) or Delta-1(ext-IgG) were first immobilized on the plastic surface. However, Notch was not activated by either monomeric or dimeric ligand in solution (non-immobilized). Furthermore, both non-immobilized Delta-1(ext-myc) and Delta-1(ext-IgG) blocked the effect of immobilized Delta. These results indicate that Delta-1 extracellular domain must be immobilized to induce Notch activation in C2 or U20S cells and that non-immobilized Delta-1 extracellular domain is inhibitory to Notch function. These results imply that ligand stabilization may be essential for Notch activation.

Interactions among Delta, Serrate and Fringe modulate Notch activity during Drosophila wing development

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2951-2962 ◽  
Author(s):  
T. Klein ◽  
A.M. Arias
Keyword(s):  
Notch Signalling ◽  
Dominant Negative ◽  
Wing Development ◽  
Notch Signalling Pathway ◽  
Notch Ligand ◽  
Drosophila Wing ◽  
Signalling Molecule ◽  
Dorsoventral Boundary ◽  
Notch Ligands ◽  
Specific Nuclear Protein

The Notch signalling pathway plays an important role during the development of the wing primordium, especially of the wing blade and margin. In these processes, the activity of Notch is controlled by the activity of the dorsal specific nuclear protein Apterous, which regulates the expression of the Notch ligand, Serrate, and the Fringe signalling molecule. The other Notch ligand, Delta, also plays a role in the development and patterning of the wing. It has been proposed that Fringe modulates the ability of Serrate and Delta to signal through Notch and thereby restricts Notch signalling to the dorsoventral boundary of the developing wing blade. Here we report the results of experiments aimed at establishing the relationships between Fringe, Serrate and Delta during wing development. We find that Serrate is not required for the initiation of wing development but rather for the expansion and early patterning of the wing primordium. We provide evidence that, at the onset of wing development, Delta is under the control of apterous and might be the Notch ligand in this process. In addition, we find that Fringe function requires Su(H). Our results suggest that Notch signalling during wing development relies on careful balances between positive and dominant negative interactions between Notch ligands, some of which are mediated by Fringe.

Effects of SEL-12 presenilin on LIN-12 localization and function in Caenorhabditis elegans

Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3599-3606 ◽  
Author(s):  
D. Levitan ◽  
I. Greenwald
Keyword(s):  
Plasma Membranes ◽  
General Factor ◽  
Missense Mutations ◽  
Protein Activity ◽  
App Processing ◽  
Notch Activity ◽  
C Elegans ◽  
Vulval Precursor Cells ◽  
Genes Encoding ◽  
And Function

Presenilins have been implicated in the development of Alzheimer's disease and in facilitating LIN-12/Notch activity. Here, we use genetic methods to explore the relationship between C. elegans LIN-12 and SEL-12 presenilin. Reducing sel-12 activity can suppress the effects of elevated lin-12 activity when LIN-12 is activated by missense mutations but not when LIN-12 is activated by removal of the extracellular and transmembrane domains. These results suggest that SEL-12 does not function downstream of activated LIN-12. An active SEL-12::GFP hybrid protein accumulates in the perinuclear region of the vulval precursor cells (VPCs) of living hermaphrodites, consistent with a localization in endoplasmic reticulum/Golgi membranes; when sel-12 activity is reduced, less LIN-12 protein accumulates in the plasma membranes of the VPCs. Together with the genetic interactions between lin-12 and sel-12, these observations suggest a role for SEL-12 in LIN-12 processing or trafficking. However, SEL-12 does not appear to be a general factor that influences membrane protein activity, since reducing sel-12 activity does not suppress or enhance hypomorphic mutations in other genes encoding membrane proteins. We discuss potential parallels for the role of SEL-12/presenilin in facilitating LIN-12/Notch activity and in amyloid precursor protein (APP) processing.

Vertebrate retinal ganglion cells are selected from competent progenitors by the action of Notch

Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3637-3650 ◽  
Author(s):  
C.P. Austin ◽  
D.E. Feldman ◽  
J.A. Ida ◽  
C.L. Cepko
Keyword(s):  
Cell Fate ◽  
Ganglion Cells ◽  
Notch Pathway ◽  
Cell Types ◽  
Projection Neurons ◽  
Specific Cell ◽  
Vitro Assay ◽  
Notch Activity

The first cells generated during development of the vertebrate retina are the ganglion cells, the projection neurons of the retina. Although they are one of the most intensively studied cell types within the central nervous system, little is known of the mechanisms that determine ganglion cell fate. We demonstrate that ganglion cells are selected from a large group of competent progenitors that comprise the majority of the early embryonic retina and that differentiation within this group is regulated by Notch. Notch activity in vivo was diminished using antisense oligonucleotides or augmented using a retrovirally transduced constitutively active allele of Notch. The number of ganglion cells produced was inversely related to the level of Notch activity. In addition, the Notch ligand Delta inhibited retinal progenitors from differentiating as ganglion cells to the same degree as did activated Notch in an in vitro assay. These results suggest a conserved strategy for neurogenesis in the retina and describe a versatile in vitro and in vivo system with which to examine the action of the Notch pathway in a specific cell fate decision in a vertebrate.

Conservation of the Notch signalling pathway in mammalian neurogenesis

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1139-1148 ◽  
Author(s):  
J.L. Pompa de la ◽  
A. Wakeham ◽  
K.M. Correia ◽  
E. Samper ◽  
S. Brown ◽  
...  
Keyword(s):  
Cell Fate ◽  
Notch Pathway ◽  
Stem Cell Differentiation ◽  
Notch Signalling ◽  
Signalling Pathway ◽  
Notch Signalling Pathway ◽  
Altered Expression ◽  
Cell Fate Decisions ◽  
Targeted Mutation ◽  
Multiple Cell

The Notch pathway functions in multiple cell fate determination processes in invertebrate embryos, including the decision between the neuroblast and epidermoblast lineages in Drosophila. In the mouse, targeted mutation of the Notch pathway genes Notch1 and RBP-Jk has demonstrated a role for these genes in somite segmentation, but a function in neurogenesis and in cell fate decisions has not been shown. Here we show that these mutations lead to altered expression of the Notch signalling pathway homologues Hes-5, Mash-1 and Dll1, resulting in enhanced neurogenesis. Precocious neuronal differentiation is indicated by the expanded expression domains of Math4A, neuroD and NSCL-1. The RBP-Jk mutation has stronger effects on expression of these genes than does the Notch1 mutation, consistent with functional redundancy of Notch genes in neurogenesis. Our results demonstrate conservation of the Notch pathway and its regulatory mechanisms from fly to mouse, and support a role for the murine Notch signalling pathway in the regulation of neural stem cell differentiation.

scholarly journals Radical and lunatic fringes modulate notch ligands to support mammalian intestinal homeostasis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Preetish Kadur Lakshminarasimha Murthy ◽  
Tara Srinivasan ◽  
Matthew S Bochter ◽  
Rui Xi ◽  
Anastasia Kristine Varanko ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Secretory Cells ◽  
Notch Activity ◽  
Crypt Base ◽  
Notch Ligands ◽  
Cell Zone

Notch signalling maintains stem cell regeneration at the mouse intestinal crypt base and balances the absorptive and secretory lineages in the upper crypt and villus. Here we report the role of Fringe family of glycosyltransferases in modulating Notch activity in the two compartments. At the crypt base, RFNG is enriched in the Paneth cells and increases cell surface expression of DLL1 and DLL4. This promotes Notch activity in the neighbouring Lgr5+ stem cells assisting their self-renewal. Expressed by various secretory cells in the upper crypt and villus, LFNG promotes DLL surface expression and suppresses the secretory lineage . Hence, in the intestinal epithelium, Fringes are present in the ligand-presenting ‘sender’ secretory cells and promote Notch activity in the neighbouring ‘receiver’ cells. Fringes thereby provide for targeted modulation of Notch activity and thus the cell fate in the stem cell zone, or the upper crypt and villus.

scholarly journals Ventralization of the Drosophila embryo by deletion of extracellular leucine-rich repeats in the Toll protein.

1995 ◽  
Vol 6 (5) ◽  
pp. 587-596 ◽  
Author(s):  
K A Winans ◽  
C Hashimoto
Keyword(s):  
Cell Fate ◽  
Transmembrane Protein ◽  
Signal Transduction Pathway ◽  
Extracellular Domain ◽  
Drosophila Embryo ◽  
Transduction Pathway ◽  
Wild Type ◽  
Truncated Form ◽  
Biochemical Analyses ◽  
Leucine Rich Repeats

Dorsoventral polarity of the Drosophila embryo is established by a signal transduction pathway in which the maternal transmembrane protein Toll appears to function as the receptor for a ventrally localized extracellular ligand. Certain dominant Toll alleles encode proteins that behave as partially ligand-independent receptors, causing embryos containing these proteins to become ventralized. In extracts of embryos derived from mothers carrying these dominant alleles, we detected a polypeptide of approximately 35 kDa in addition to full-length Toll polypeptides with antibodies to Toll. Our biochemical analyses suggest that the smaller polypeptide is a truncated form of Toll lacking extracellular domain sequences. To assay the biological activity of such a shortened form of Toll, we synthesized RNA encoding a mutant polypeptide lacking the leucine-rich repeats that comprise most of Toll's extracellular domain and injected this RNA into embryos. The truncated Toll protein elicited the most ventral cell fate independently of the wild-type Toll protein and its ligand. These results support the view that Toll is a receptor whose extracellular domain regulates the intrinsic signaling activity of its cytoplasmic domain.

PTPN11 Mutational Spectrum in Juvenile Myelomonocytic Leukemia and Noonan Syndrome.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3417-3417 ◽  
Author(s):  
Christian P. Kratz ◽  
Charlotte M. Niemeyer ◽  
Bruce D. Gelb ◽  
Marco Tartaglia ◽  
Mignon L. Loh
Keyword(s):  
Cell Fate ◽  
Noonan Syndrome ◽  
Somatic Mutations ◽  
Heart Defects ◽  
Lymphoblastic Leukemia ◽  
Juvenile Myelomonocytic Leukemia ◽  
Acute Monocytic Leukemia ◽  
Missense Mutations ◽  
Ptpn11 Mutation ◽  
Myelomonocytic Leukemia

Abstract Somatic, heterozygous missense mutations in the PTPN11 proto-oncogene encoding SHP-2 are identified in 35% of patients with juvenile myelomonocytic leukemia (JMML). Other non-syndromic hematologic malignancies in which somatic PTPN11 mutations have been detected are pediatric myelodysplastic syndrome, acute monocytic leukemia (FAB-M5 AML) and common or B-cell precursor acute lymphoblastic leukemia. Germline PTPN11 mutations are found in 50% of patients with Noonan syndrome (NS), an autosomal dominant disorder characterized by facial anomalies, short stature and congenital heart defects. Infants with NS are predisposed to developing JMML (NS/JMML); however, the course of NS/JMML tends to be milder and self-resolving. JMML that is not associated with NS have a poor prognosis and are currently being treated with intensive regimens such stem cell transplantation. Differentiating JMML from NS/JMML is of critical clinical relevance and also provides interesting questions about the pathogenesis of these diseases. To that end, we have compared the spectrum of mutations in patients with isolated JMML, NS/JMML and NS alone. The assembly of all known published and unpublished germline and somatic exon 3 and 13 PTPN11 mutations detected in ours and other laboratories (78 pts with PTPN11 mutation positive isolated JMML; 18 pts with PTPN11 mutation positive NS/JMML) reveal that the identity of the affected residues or the type of substitution differ between NS and JMML, even though the resulting molecular defects appear to be functionally similar. In NS defects in exons 4, 7 and 8 account for approximately one-half of cases. On the contrary, mutations affecting these exons are rarely identified in JMML. A few germline NS-causative mutations affect the same residues of SHP-2 that are also altered by somatic mutations in non-syndromic JMML. In almost all of the cases, the germline and somatic mutations affecting identical residues differ with respect to the amino acid substitution. There are 2 major hot spots: 7 out of 18 patients (39%) with NS/JMML carry the T73I substitution. In isolated JMML the E76K mutation is detected most often (18 out of 78 patients (23%)). We describe 2 novel JMML mutations (E76M, G503V) and 2 novel NS/JMML mutations (R598W, S502A). Six mutations associated with isolated NS are also observed in NS/JMML. These findings imply the presence of a germline mutation needs to be excluded in all mutation positive neonates with presumed isolated JMML. In addition, our findings raise a number of research questions: First, are somatic PTPN11 mutations alone sufficient to initate leukemia and what are the molecular factors influencing the consequences of a PTPN11 mutation in hematopoietic cells? Second, do identical mutations have different consequences on cell fate of hematopoetic cells depending on whether they occur as germline or somatic events? Do some patients with isolated NS and PTPN11 mutation develop transient myeloproliferation of hematopoetic cells which may be subtle and unrecognised?

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