Search results for "Homeobox"

The Echinoid hbox12/pmar1/micro1 multigene family: expression, functions and evolution

2017

The aristaless (Arx) gene: one gene for many "interneuronopathies".

2009

The ARX (Aristaless-related (X-linked) homeobox) gene is not only present in arthropods and their ancestors, but also in vertebrates including humans (ARX orthologs). The gene is composed of 5 coding exons and it is expressed predominantly in foetal and adult brain and skeletal muscle. In this review we report on our experience and review the existing literature on the genotype and phenotype heterogeneity associated with ARX abnormalities in humans ranging from severe neuronal migration defects (e.g., lissencephaly), to mild forms of X-linked mental retardation without apparent brain abnormalities. The ARX-related disorders are reviewed focusing on their clinical features and on the role of…

Age-dependent epileptic encephalopathy associated with an unusual co-occurrence of ZEB2 and SCN1A variants.

2020

Mowat-Wilson syndrome is a genetic disorder associated with a variable phenotype including peculiar facial features associated with intellectual disability, epilepsy, language impairment, and multiple congenital anomalies caused by heterozygous mutation of the ZEB2 gene. The ZEB2 protein is a complex transcription factor that encompasses multiple functional domains that interact with the regulatory regions of target genes including those involved in brain development. Recently, it has been documented that ZEB2 regulates the differentiation of interneuron progenitors migrating from the medial ganglionic eminence to cortical layers by repression of the Nkx2-1 homeobox transcription factor. It…

Segment polarity and DV patterning gene expression reveals segmental organization of theDrosophilabrain

2003

The insect brain is traditionally subdivided into the trito-, deuto- and protocerebrum. However, both the neuromeric status and the course of the borders between these regions are unclear. The Drosophila embryonic brain develops from the procephalic neurogenic region of the ectoderm, which gives rise to a bilaterally symmetrical array of about 100 neuronal precursor cells, called neuroblasts. Based on a detailed description of the spatiotemporal development of the entire population of embryonic brain neuroblasts, we carried out a comprehensive analysis of the expression of segment polarity genes (engrailed, wingless, hedgehog, gooseberry distal,mirror) and DV patterning genes (muscle segmen…

EphrinB2 repression through ZEB2 mediates tumour invasion and anti-angiogenic resistance.

2016

Diffuse invasion of the surrounding brain parenchyma is a major obstacle in the treatment of gliomas with various therapeutics, including anti-angiogenic agents. Here we identify the epi-/genetic and microenvironmental downregulation of ephrinB2 as a crucial step that promotes tumour invasion by abrogation of repulsive signals. We demonstrate that ephrinB2 is downregulated in human gliomas as a consequence of promoter hypermethylation and gene deletion. Consistently, genetic deletion of ephrinB2 in a murine high-grade glioma model increases invasion. Importantly, ephrinB2 gene silencing is complemented by a hypoxia-induced transcriptional repression. Mechanistically, hypoxia-inducible facto…

Osteogenic commitment and differentiation of human mesenchymal stem cells by low‐intensity pulsed ultrasound stimulation

2018

Low-intensity pulsed ultrasound (LIPUS) as an adjuvant therapy in in vitro and in vivo bone engineering has proven to be extremely useful. The present study aimed at investigating the effect of 30 mW/cm(2) LIPUS stimulation on commercially available human mesenchymal stem cells (hMSCs) cultured in basal or osteogenic medium at different experimental time points (7d, 14d, 21d). The hypothesis was that LIPUS would improve the osteogenic differentiation of hMSC and guarantying the maintenance of osteogenic committed fraction, as demonstrated by cell vitality and proteomic analysis. LIPUS stimulation (a) regulated the balance between osteoblast commitment and differentiation by specific network…

The ladybird homeobox genes are essential for the specification of a subpopulation of neural cells

2004

AbstractIn Drosophila, neurons and glial cells are produced by neural precursor cells called neuroblasts (NBs), which can be individually identified. Each NB generates a characteristic cell lineage specified by a precise spatiotemporal control of gene expression within the NB and its progeny. Here we show that the homeobox genes ladybird early and ladybird late are expressed in subsets of cells deriving from neuroblasts NB 5-3 and NB 5-6 and are essential for their correct development. Our analysis revealed that ladybird in Drosophila, like their vertebrate orthologous Lbx1 genes, play an important role in cell fate specification processes. Among those cells that express ladybird are NB 5-6…

Six3 demarcates the anterior-most developing brain region in bilaterian animals

2010

Abstract Background The heads of annelids (earthworms, polychaetes, and others) and arthropods (insects, myriapods, spiders, and others) and the arthropod-related onychophorans (velvet worms) show similar brain architecture and for this reason have long been considered homologous. However, this view is challenged by the 'new phylogeny' placing arthropods and annelids into distinct superphyla, Ecdysozoa and Lophotrochozoa, together with many other phyla lacking elaborate heads or brains. To compare the organisation of annelid and arthropod heads and brains at the molecular level, we investigated head regionalisation genes in various groups. Regionalisation genes subdivide developing animals …

Clinical spectrum of eye malformations in four patients with Mowat-Wilson syndrome

2015

Mowat-Wilson syndrome (MWS) is a rare genetic syndrome characterized by a specific facial gestalt, intellectual deficiency, Hirschsprung disease and multiple congenital anomalies. Heterozygous mutations or deletions in the zinc finger E-box-binding homeobox2 gene (ZEB2) cause MWS. ZEB2 encodes for Smad-interacting protein 1, a transcriptional co-repressor involved in TGF-beta and BMP pathways and is strongly expressed in early stages of development in mice. Eye abnormalities have rarely been described in patients with this syndrome. Herein, we describe four patients (two males and two females; mean age 7 years) with MWS and eye malformations. Ocular anomalies included, iris/retinal coloboma…

The transcription factor ZEB1 (deltaEF1) promotes tumour cell dedifferentiation by repressing master regulators of epithelial polarity.

2007

Epithelial to mesenchymal transition (EMT) is implicated in the progression of primary tumours towards metastasis and is likely caused by a pathological activation of transcription factors regulating EMT in embryonic development. To analyse EMT-causing pathways in tumouri-genesis, we identified transcriptional targets of the E-cadherin repressor ZEB1 in invasive human cancer cells. We show that ZEB1 repressed multiple key determinants of epithelial differentiation and cell–cell adhesion, including the cell polarity genes Crumbs3, HUGL2 and Pals1-associated tight junction protein. ZEB1 associated with their endogenous promoters in vivo, and strongly repressed promotor activities in reporter …