The Clathrin adaptor AP-1 and Stratum act in parallel pathways to control Notch activation in sensory organ precursors cells.

sensory organ precursors divide asymmetrically to generate pIIa/pIIb cells, the identity of which relies on activation of Notch at cytokinesis. Although Notch is present apically and basally relative to the midbody at the pIIa-pIIb interface, the basal pool of Notch is reported to be the main contributor for Notch activation in the pIIa cell. Intra-lineage signalling requires appropriate apico-basal targeting of Notch, its ligand Delta and its trafficking partner Sanpodo.

Stratum recruits Rab8 at Golgi exit sites to regulate the basolateral sorting of Notch and Sanpodo.

In , the sensory organ precursor (SOP or pI cell) divides asymmetrically to give birth to daughter cells, the fates of which are governed by the differential activation of the Notch pathway. Proteolytic activation of Notch induced by ligand is based on the correct polarized sorting and localization of the Notch ligand Delta, the Notch receptor and its trafficking partner Sanpodo (Spdo). Here, we have identified Stratum (Strat), a presumptive guanine nucleotide exchange factor for Rab GTPases, as a regulator of Notch activation.

Novel genes upregulated when NOTCH signalling is disrupted during hypothalamic development.

Background: The generation of diverse neuronal types and subtypes from multipotent progenitors during development is crucial for assembling functional neural circuits in the adult central nervous system. It is well known that the Notch signalling pathway through the inhibition of proneural genes is a key regulator of neurogenesis in the vertebrate central nervous system. However, the role of Notch during hypothalamus formation along with its downstream effectors remains poorly defined.

NODAL and SHH dose-dependent double inhibition promotes an HPE-like phenotype in chick embryos.

Holoprosencephaly (HPE) is a common congenital defect that results from failed or incomplete forebrain cleavage. HPE is characterized by a wide clinical spectrum, with inter- and intrafamilial variability. This heterogeneity is not well understood and it has been suggested that HPE involves a combination of multiple gene mutations.

New findings for phenotype-genotype correlations in a large European series of holoprosencephaly cases.

Background: Holoprosencephaly (HPE) is the most common forebrain defect in humans. It results from incomplete midline cleavage of the prosencephalon.

Methods: A large European series of 645 HPE probands (and 699 relatives), consisting of 51% fetuses and 49% liveborn children, is reported.

NOTCH, a new signaling pathway implicated in holoprosencephaly.

Genetics of Holoprosencephaly (HPE), a congenital malformation of the developing human forebrain, is due to multiple genetic defects. Most genes that have been implicated in HPE belong to the sonic hedgehog signaling pathway. Here we describe a new candidate gene isolated from array comparative genomic hybridization redundant 6qter deletions, DELTA Like 1 (DLL1), which is a ligand of NOTCH.

Holoprosencephaly: An update on cytogenetic abnormalities.

Holoprosencephaly (HPE), the most common developmental defect of the forebrain and midface, is caused by a failure of midline cleavage early in gestation. Isolated HPE, which is highly genetically heterogeneous, can be due to major chromosomal abnormalities. Initially, karyotype approach led to the identification of several recurrent chromosomal anomalies predicting different HPE loci.

Array-CGH analysis indicates a high prevalence of genomic rearrangements in holoprosencephaly: an updated map of candidate loci.

Holoprosencephaly (HPE) is the most frequent malformation of the brain. To date, 12 different HPE loci and 8 HPE genes have been identified from recurrent chromosomal rearrangements or from the sequencing of genes from Nodal and SHH pathways. Our cohort of HPE patients presents a high genetic heterogeneity.

MLPA screening reveals novel subtelomeric rearrangements in holoprosencephaly.

Holoprosencephaly (HPE) is the most common developmental brain anomaly in human, associated with a wide spectrum of presentations. The etiology is heterogeneous, due to environmental and genetic factors. Out of 12 cytogenetic candidate loci previously reported, eight were subtelomeric, including the loci in which two of the four major HPE genes were identified (SHH and TGIF).

Phenotypic variability of a 4q34-->qter inherited deletion: MRKH syndrome in the daughter, cardiac defect and Fallopian tube cancer in the mother.

Terminal deletions of the long arm of chromosome 4 are associated with a recognizable phenotype consisting of dysmorphic facial features, cleft palate, upper and lower limb malformations, cardiac defects and growth and mental retardation. Here we report on two female patients, a mother and her daughter, carrying the same 4q34-->qter deletion but presenting with a different phenotype. The mother's presentation is consistent with previous findings in patients with terminal deletions of the long arm of chromosome 4.

Molecular evaluation of foetuses with holoprosencephaly shows high incidence of microdeletions in the HPE genes.

Holoprosencephaly (HPE), the most common structural malformation of the forebrain in humans, can be detected early during pregnancy using prenatal ultrasonography . Among foetuses with a normal karyotype, 14% have mutations in the four main HPE genes (SHH, ZIC2, SIX3 and TGIF). Genomic rearrangements have now been implicated in many genetic diseases, so we hypothesized that microdeletions in the major HPE genes may also be common in HPE foetuses with severe phenotype or other associated malformations.

Transcriptome variations in human CaCo-2 cells: a model for enterocyte differentiation and its link to iron absorption.

Complete clinical expression of the HFE1 hemochromatosis is very likely modulated by genes linked to duodenal iron absorption, whose level is conditioned by unknown processes taking place during enterocyte differentiation. We carried out a transcriptomic study on CaCo-2 cells used as a model of enterocyte differentiation in vitro. Of the 720 genes on the microarrays, 80, 50, and 56 were significantly down-regulated up-regulated, and invariant during differentiation.