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M Abitbol

Publications and source records attributed to M Abitbol.

At least 55 records · Page 3Linked to original sources
PubMed1998

Identification of a new heterozygous point mutation in the COL1A2 gene leading to skipping of exon 9 in a patient with joint laxity, hyperextensibility of skin and blue sclerae. Mutations in brief no. 166. Online.

A heterozygous deletion of exon 9 in the COL1A2-mRNA of a patient with symptoms of both the Ehlers-Danlos-Syndrome and the Osteogensis Imperfecta is described. In the genomic DNA of the patient, exon 9 is homozygously present. We identified a novel heterozygous point mutation in the splice donor site of intron 9, leading to a G-->A substitution in position +5. This mutation leads to heterozygous skipping of exon 9 in the COL1A2-mRNA of this patient. The deletion results in a shortened (by 18 amino acids) but in frame 12(1) chain, which probably leads to the formation of abberantly processed triple helices.

Alternative Splicing↗
PubMed1998

Insulin-like 4 (INSL4) gene expression in human embryonic and trophoblastic tissues.

Polypeptide growth factors play an important role in the regulation of human embryonic development. Insulin-like 4 gene (INSL4) is a member of the insulin family, which includes insulin, IGF-I, IGF-II, relaxin, and INSL3. Using RT-PCR, we previously found abundant INSL4 mRNA in the human placenta. In this study, we examined the chronology and spatial expression of this gene in sections of human placenta and conceptus by means of in situ hybridization. Expression of the IGF-II gene was studied as a positive control. INSL4 distribution was tissue- and cell-specific. Indeed, INSL4 mRNA was most abundant in syncytiotrophoblast cells. In fetal tissues, INSL4 mRNA was identified in the perichondrium of all four limbs, vertebrae, and ribs. Moreover, INSL4 mRNA was abundant in interbone ligaments. These findings indicate that the INSL4 gene may play an important role in trophoblast development and regulation of bone formation. IGF-II mRNA, in agreement with the literature, are mainly located in the mesodermal core in the villous trophoblast and in most embryonic tissues.

Gene Expression Regulation, Developmental↗
PubMed1998

Gillespie syndrome phenotype with a t(X;11)(p22.32;p12) de novo translocation.

PURPOSE: To report a patient with a phenotype suggestive of Gillespie syndrome and with a chromosomal abnormality. METHODS: Clinical evaluation showed bilateral superior coloboma, foveal hypoplasia, and inferior cerebellar hypoplasia. Karyotyping as well as investigation of the PAX6 gene were performed. RESULTS: The karyotype of the patient disclosed a de novo translocation t(X;11)(p22.32;p12). Fluorescent in situ hybridization and the search for mutations excluded direct implication of the PAX6 gene. CONCLUSION: This is, to our knowledge, the first report of a chromosomal abnormality detected in a patient with a Gillespie syndrome phenotype.

Abnormalities, Multiple↗
PubMed1998

From CRX to CRD.

Explore the source record for details and available documents.

Animals↗
PubMed1998

Mapping of a congenital microcoria locus to 13q31-q32.

Congenital microcoria is an autosomal dominant disorder characterized by a pupil with a diameter <2 mm. It is thought to be due to a maldevelopment of the dilator pupillae muscle of the iris, and it is associated with juvenile-onset glaucoma. A total genome search for the location of the congenital microcoria gene was launched in a single large family. We found linkage between the disease and markers located on 13q31-q32 (Zmax = 9.79; theta = 0). Haplotype analysis narrowed the linked region to an interval <8 cM between markers D13S1239 proximally and D13S1280 distally.

Chromosome Mapping↗
PubMed1998

[Computed tomography of intrahepatic pancreatic pseudocysts].

PURPOSE: Intrahepatic pseudocyst complicating pancreatitis is a rare event. The goals of this paper are to report the computed tomographic (CT) features of intrahepatic pseudocyst and to analyze the role of percutaneous puncture and percutaneous drainage in the diagnosis and treatment of intrahepatic pseudocyst. MATERIAL AND METHODS: Three cases of intrahepatic pseudocyst studied by CT were retrospectively reviewed. Percutaneous puncture of the intrahepatic pseudocyst was performed in two cases, and was subsequently followed by percutaneous drainage of the intrahepatic pseudocyst in one case. RESULTS: In the three cases, intrahepatic pseudocysts appeared like multiple, hypoattenuating, homogeneous intrahepatic fluid collections, associated with intrahepatic bile duct dilatation in one case. In the two cases in which it was performed, percutaneous puncture of the pseudocyst revealed an elevated amylase level, thus confirming the diagnosis. In one case, percutaneous puncture revealed superinfection, thus indicating percutaneous drainage of the pseudocyst. CONCLUSION: The diagnosis of intrahepatic pseudocyst should be suggested in the presence of pancreatic lesions and a single or multiple intrahepatic fluid collections visible on CT. CT allows percutaneous puncture of the pseudocyst to be done, thus confirming the diagnosis and indicating subsequent performance of percutaneous drainage in complicated cases.

Aged↗
PubMed1997

Expression of myosin VIIA during mouse embryogenesis.

The gene encoding myosin VIIA is responsible for the mouse shaker-1 phenotype, which consists of deafness and balance deficiency related to cochlear and vestibular neuroepithelial defects. In humans, a defective myosin VIIA gene is responsible for Usher syndrome type IB, which associates congenital deafness, vestibular dysfunction and retinitis pigmentosa. In an attempt to progress in the understanding of the function(s) of myosin VIIA, we studied the expression of the myosin VIIA gene during mouse embryonic development. Embryos from day 9 (E9) to E18 were analyzed by in situ hybridization and immunohistofluorescence. The myosin VIIA mRNA and protein were consistently detected in the same embryonic tissues throughout development. Myosin VIIA was first observed in the otic vesicle at E9, and later in a variety of tissues. The olfactory epithelium and the liver express it as early as E10. In the retinal pigment epithelium, choroid plexus, adrenal gland and tongue, expression begins at E12 and in the testis and the adenohypophysis at E13. In the small intestine, kidney and hair follicles of the vibrissae, expression of myosin VIIA starts only at E15. Myosin VIIA expression was observed only in epithelial cell types, most of which possess microvilli or cilia. Interestingly, myosin VIIA expression seems to be concomitant with the appearance of these structures in the epithelial cells, suggesting a role for this myosin in their morphogenesis. The cellular location of myosin VIIA within sensory hair cells and olfactory receptor neurons also argues for a role of this protein in the synaptic vesicle trafficking.

Adrenal Glands↗
PubMed1997

In vivo adenovirus-mediated gene transfer to newborn rat retinal pigment epithelial cells.

A successful surgical access to the subretinal space is critical for achieving adenovirus-mediated gene transfer to the retinal pigment epithelial (RPE) cells or photoreceptor cells. We report a novel surgical approach allowing an efficient delivery of recombinant replication-deficient adenoviral vectors into the subretinal space of newborn rats. Our data suggest that this method may be useful for infecting reproducibly large area of the RPE cell layer of normal newborn rats and should be applicable to RCS pups. We also show the feasibility of infecting ex vivo RPE cells in culture using the same recombinant adenoviral vector.

Animals↗
PubMed1997

Moderate intergenerational and somatic instability of a 55-CTG repeat in transgenic mice.

Myotonic dystrophy (DM) is associated with the expansion of a (CTG)n trinucleotide repeat in the 3' untranslated region (UTR) of the DM protein kinase gene (DMPK). The (CTG)n repeat is polymorphic and varies in size between 5 and 37 repeats in unaffected individuals whereas in affected patients there are between 50 and 4,000 CTGs. The size of the (CTG)n repeat, which increases through generations, generally correlates with clinical severity and age of onset. The instability of the CTG repeat appears to depend on its size as well as on the sex of the transmitting parent. Moreover, mitotic instability analysis of different human DM tissues shows length mosaicism between different cell lineages. The molecular mechanisms of triplet instability remain elusive. To investigate the role of genomic sequences in instability, we produced transgenic mice containing a 45-kb genomic segment with a 55-CTG repeat cloned from a mildly affected patient. In contrast to other mouse models containing CAG repeats within cDNAs, these mice showed both intergenerational and somatic repeat instability.

Animals↗
PubMed1997

A new dimension for the human genome project: towards comprehensive expression maps.

The current Human Genome Project is largely devoted to structural characterisation of our genome. We now need international co-ordination of a second phase of genome analysis, the systematic construction of expression maps using both basic and high-resolution expression assays. Databases recording different types of expression pattern for a variety of human cell types need to be established and co-ordinated. There is a compelling need for a database of gene expression in early human development, but the scarcity of human material for study requires optimisation of research strategies and co-ordination of expression studies in early human and mouse development.

Animals↗
PubMed1997

SOX22 is a new member of the SOX gene family, mainly expressed in human nervous tissue.

SOX (SRY box-containing) genes share a particular DNA-binding domain, called HMG, with the mammalian testis-determining gene SRY Several SOX genes have already been shown to be transcription factors involved in the decision of important cell fates during development. Here we report the cloning of a new human member of the SOX gene family, SOX22. The corresponding protein contains several domains that are also present in other paralogous SOX proteins. The SOX22 gene maps to chromosome 20 on band p13 and does not appear to be clustered with any other SOX gene mapped to date. SOX22 mRNA is expressed in various fetal and adult organs and tissues, suggesting that this gene plays roles in both differentiation and maintenance of several cell types.

Age Factors↗
PubMed1996

Characterization and chromosomal localization of the gene for human rhodopsin kinase.

G-protein-dependent receptor kinases (GRKs) play a key role in the adaptation of receptors to persistent stimuli. In rod photoreceptors rhodopsin kinase (RK) mediates rapid desensitization of rod photoreceptors to light by catalyzing phosphorylation of the visual pigment rhodopsin. To study the structure and mechanism of GRKs in human photoreceptors, we have isolated and characterized cDNA and genomic clones derived from the human RK locus using a bovine rhodopsin kinase cDNA fragment as a probe. The RK locus, assigned to chromosome 13 band q34, is composed of seven exons that encode a protein 92% identical in amino acid sequence to bovine rhodopsin kinase. The marked difference between the structure of this gene and that of another recently cloned human GRK gene suggests the existence of a wide evolutionary gap between members of the GRK gene family.

Amino Acid Sequence↗
PubMed1996

Human myosin VIIA responsible for the Usher 1B syndrome: a predicted membrane-associated motor protein expressed in developing sensory epithelia.

The gene encoding human myosin VIIA is responsible for Usher syndrome type III (USH1B), a disease which associates profound congenital sensorineural deafness, vestibular dysfunction, and retinitis pigmentosa. The reconstituted cDNA sequence presented here predicts a 2215 amino acid protein with a typical unconventional myosin structure. This protein is expected to dimerize into a two-headed molecule. The C terminus of its tail shares homology with the membrane-binding domain of the band 4.1 protein superfamily. The gene consists of 48 coding exons. It encodes several alternatively spliced forms. In situ hybridization analysis in human embryos demonstrates that the myosin VIIA gene is expressed in the pigment epithelium and the photoreceptor cells of the retina, thus indicating that both cell types may be involved in the USH1B retinal degenerative process. In addition, the gene is expressed in the human embryonic cochlear and vestibular neuroepithelia. We suggest that deafness and vestibular dysfunction in USH1B patients result from a defect in the morphogenesis of the inner ear sensory cell stereocilia.

Alternative Splicing↗
PubMed1996

Human Usher 1B/mouse shaker-1: the retinal phenotype discrepancy explained by the presence/absence of myosin VIIA in the photoreceptor cells.

Usher syndrome type 1 (USH1) associates severe congenital deafness, vestibular dysfunction and progressive retinitis pigmentosa leading to blindness. The gene encoding myosin VIIA is responsible for USH1B. Mutations in the murine orthologous gene lead to the shaker-1 phenotype, which manifests cochlear and vestibular dysfunction, without any retinal defect. To address this phenotypic discrepancy, the expression of myosin VIIA in retinal cells was analyzed in human and mouse during embryonic development and adult life. In the human embryo, myosin VIIA was present first in the pigment epithelium cells, and later in these cells as well as in the photoreceptor cells. In the adult human retina, myosin VIIA was present in both cell types. In contrast, in mouse, only pigment epithelium cells expressed the protein throughout development and adult life. Myosin VIIA was also found to be absent in the photoreceptor cells of other rodents (rat and guinea-pig), whereas these cells expressed the protein in amphibians, avians and primates. These observations suggest that retinitis pigmentosa of USH1B results from a primary rod and cone defect. The USH1B/shaker-1 paradigm illustrates a species-specific cell pattern of gene expression as a possible cause for the discrepancy between phenotypes involving defective orthologous genes in man and mouse. Interestingly, in the photoreceptor cells, myosin VIIA is mainly localized in the inner and base of outer segments as well as in the synaptic ending region where it is co-localized with the synaptic vesicles. Therefore, we suggest that myosin VIIA might play a role in the trafficking of ribbon-synaptic vesicle complexes and the renewal processes of the outer photoreceptor disks.

Adult↗
PubMed1995

The rat phospholipase C beta 4 gene is expressed at high abundance in cerebellar Purkinje cells.

Inositol phospholipid-specific phospholipase C (PLC) generates two important second messengers, inositol triphosphate and diacylglycerol. The recently cloned rat PLC beta 4 cDNA is highly homologous to the norpA cDNA of Drosophila melanogaster. We have mapped the PLC beta 4 gene expression in rat brain tissue sections by in situ hybridization. The PLC beta 4 gene is expressed at high abundance in cerebellar Purkinje cells and neurones of the substantia nigra, the median geniculate bodies and the thalamic nuclei. PLC beta 4 transcripts are also detected in the mammillary nuclei, the neocortex, the habenula and the olfactory bulbs. The specific pattern of gene expression we have observed should help to clarify the relationships between the PLC beta 4 and various constituents of second-messenger systems involved in transduction mechanisms triggered by the stimulation of seven transmembrane domain receptors. The strong gene expression in Purkinje cells and retinal neurones suggests that PLC beta 4 may be involved in the pathogenesis of mouse and human neurological diseases characterized by ataxia and retinal degeneration.

Animals↗
PubMed1995

PAX-genes expression during human embryonic development, a preliminary report.

PAX-genes encode important transcriptional factors during embryogenesis. They are also involved in human diseases, Waardenburg syndrome, Aniridia and tumors. We report in the present paper a preliminary in situ hybridization study of PAX3-, PAX5- and PAX6-gene expression during human embryonic development. PAX3-gene is expressed in the neural groove before closure, and in the closed neural tube. Afterwards, its expression is observed in the mesencephalon, the rhombencephalon and the spinal cord. PAX5-gene expression is restricted to the mesencephalon-rhombencephalon boundary and the spinal cord. PAX6-gene is expressed early in the neural tube, just after its closure. Afterwards, its expression is observed in the forebrain, the rhombencephalon, the somites and the spinal cord. These patterns of expression are observed early during human embryonic development and are specific in time and space. This preliminary report shows the feasibility of in situ hybridization methodology for studying the expression of developmental genes during the early stages of human embryogenesis. It opens the way to study the pathogenesis of polymalformative syndromes and tumorigenesis.

Chromosome Mapping↗
PubMed1994

[Pathology of opsins and vision disorders].

Mutations of the gene encoding rhodopsin are responsible for 30% of the cases autosomal dominant retinitis pigmentosa. Rhodopsin molecules are key G-coupled transmembrane proteins initiating the visual transduction cascade in rods. These cells are specialized retinal cells allowing the detection of low intensity lights. Mutations in the rhodopsin gene lead to the progressive destruction of rods, clinically translated by night blindness, a progressive bilateral loss of the peripheral visual field, and predominant alterations of the rod component of the electroretinograms. Inherited colour vision deficiencies are mainly caused by alterations of the genes encoding coloured opsins. These proteins are G-coupled receptors specialized in visual transduction in the cones. These sensorial cells are localized in the center of the neural retina where they allow the detection of refined details and chromatic lights. Rearrangements of the genes encoding the green and the red color pigments are responsible for daltonism.

Color Vision Defects↗