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Biomedical subjects

D Cherif

Publications and source records attributed to D Cherif.

14 recordsLinked to original sources
PubMed1992

The 11q23 breakpoint in acute leukemia with t(11;19)(q23;p13) is distal to those of t(4;11), t(6;11) and t(9;11).

Thirteen cosmid probes were mapped on the long arm of chromosome 11 between 11q22 and 11q24 by nonradioactive in situ hybridization. Starting with these localizations and those of other probes mapped to 11q23, four acute leukemias with translocations involving 11q23 were studied with the same method. The translocation breakpoints of the t(4;11)(q21;q23), t(6;11)(q27;q23), t(9;11)(p21-p22;q23), and t(11;19)(q23;p13) were confirmed to be distal to CD3D. The probe cC111-304 was proximal to the t(11;19) breakpoint while distal to the breakpoints of the other rearrangements. In view of the diversity of chromosomal abnormalities involving band 11q23, our finding extends the molecular heterogeneity of the breakpoint localization in leukemias with rearrangements involving 11q23.

Adolescent↗
PubMed1992

Mapping of the formin gene and exclusion as a candidate gene for the autosomal recessive form of limb-girdle muscular dystrophy.

Limb-Girdle Muscular Dystrophy (LGMD) is a myopathy with clinical and transmission heterogeneity. The recessive form, LGMD2, has been recently mapped by linkage analysis to 15q. As an attempt to identify the gene involved in this pathology, we tested as candidate gene the LD locus, called LD for limb deformity. This gene has recently been identified and mapped to chromosome 15q13-q14. It is homologous to the murine formin gene which is localized to mouse chromosome 2. Mutations in this murine gene have been shown to cause limb deformity and kidney defect. YAC clones containing the LD gene were isolated and utilised to confirm the cytogenetic localisation. Internal DNA polymorphisms of the LD locus were analyzed in LGMD2 and CEPH families. The LD gene was mapped between the alpha cardiac actin gene and the D15S24 locus. Crossovers between the LGMD2 and the LD loci excluded the LD gene as a candidate for LGMD2.

Base Sequence↗
PubMed1991

The gene for the type II (p75) tumor necrosis factor receptor (TNF-RII) is localized on band 1p36.2-p36.3.

The gene encoding the type II (p75) tumor necrosis factor receptor (TNF-RII) has been localized on human chromosome 1, band 1p36.2 by nonradioactive in situ hybridization. The gene encoding the type I (p55) TNF-R, which is structurally homologous to the type II (p75) TNF-R, has been previously localized on chromosome 12 band 12p13. Thus, despite their probable common ancestry, the genes for the two TNF-Rs are localized on different chromosomes.

Base Sequence↗
PubMed1991

Regional mapping of the Batten disease locus (CLN3) to human chromosome 16p12.

The gene for Batten disease (CLN3) has been mapped to human chromosome 16 by demonstration of linkage to the haptoglobin locus, and its localization has been further refined using a panel of DNA markers. The aim of this work was to refine the genetic and physical mapping of this disease locus. Genetic linkage analysis was carried out in a larger group of families by using markers for five linked loci. Multipoint analysis indicated a most likely location for CLN3 in the interval between D16S67 and D16S148 (Z = 12.5). Physical mapping of linked markers was carried out using somatic cell hybrid analysis and in situ hybridization. A mouse/human hybrid cell panel containing various segments of chromosome 16 has been constructed. The relative order and physical location of breakpoints in the proximal portion of 16p were determined. Physical mapping in this panel of the markers for the loci flanking CLN3 positioned them to the bands 16p12.1----16p12.3. Fluorescent in situ hybridization of metaphase chromosomes by using these markers positioned them to the region 16p11.2-16p12.1. These results localize CLN3 to an interval of about 2 cM in the region 16p12.

Chromosome Mapping↗
PubMed1990

Two distinct mechanisms for the SCL gene activation in the t(1;14) translocation of T-cell leukemias.

Molecular study of a t(1;14)(p32;q11) translocation found in an acute T-cell leukemia (Kd cells) with a relatively mature phenotype is reported. Complex DNA rearrangements were characterized in the TCR alpha/delta locus. Besides a productive V alpha/J alpha assembly found on the normal allele, two deletions within the J alpha cluster were identified in the translocated allele. The translocation breakpoints involved the TCR delta gene on chromosome 14 and the SCL locus on chromosome band Ip32 that was recently shown to be activated by the t(1;14) translocation of the DU 528 leukemic cell line. Significantly, both Kd and DU 528 translocation breakpoints were located at the boundaries of D delta or J delta segments and were clustered in a 10 kb genomic fragment of the SCL gene. The presence of recombination signal motifs (heptamer-12/23 bp spacer-nonamer) on both normal chromosome partners, and N nucleotide addition on both derivative chromosomes involved the recombinase system in the translocation event. The SCL locus was highly expressed as a 5 kb transcript in Kd cells and, as already reported, as a 2 kb transcript in DU 528 cells. Importantly, a 5 kb SCL transcript was also detected in immature nonlymphoid hematopoietic cells but not in normal mature T cells, suggesting that it might correspond to the normal SCL transcript. Taken together, our data support the notion that the involvement of the SCL gene in the leukemogenic process may occur through overexpression of an apparently normal transcript (Kd cells) or expression of a truncated RNA (DU 528 cells).

Amino Acid Sequence↗
PubMed1990

New localizations of VH sequences by in situ hybridization with biotinylated probes.

The chromosomal localization of genes of three VH families (VH 1-3) was performed using in situ hybridization with biotinylated probes. Significantly strong signals were observed on chromosome 14, band 14q32, and on bands 16p11 and 15q11, although less frequently. Signal intensity and frequency were more important on chromosome 14 with all three probes, and on chromosome 16 with the VH2 and VH3 probes, while chromosome 15 was more marked than 16 with the VH1 probe. The localization of VH gene on chromosomes other than 14 suggests that several genes of the VH family had been simultaneously translocated in evolution and that the newly localized VH sequences may be pseudogenes.

Biotin↗
PubMed1990

In situ hybridization ascertains the presence of a translocation t(6;11) in an acute monocytic leukemia.

In situ hybridization was performed in a case of acute monoblastic leukemia (FAB type M5b) with a rearrangement of the long arm of chromosome 11. Cytogenetic analysis after R- and G-banding showed an apparent deletion of 11q with a breakpoint at 11q23, and a translocation t(6;11) was suspected in certain metaphases. In situ hybridization with a biotinylated cosmid probe hybridizing at 11q25 confirmed the translocation t(6;11)(q27;q23). Use of nonradioactive in situ hybridization techniques for more precise characterization of chromosomal rearrangements in malignant cells is emphasized.

Bone Marrow↗
PubMed1990

Gene mapping.

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Chromosome Mapping↗
PubMed1990

Simultaneous localization of cosmids and chromosome R-banding by fluorescence microscopy: application to regional mapping of human chromosome 11.

A technique for nonradioactive in situ hybridization on human metaphase chromosomes has been developed to localize human cosmid clones. The simple procedure using two fluorescent dyes (fluorescein and propidium iodide) allows the simultaneous identification of chromosomal R-bands and hybridization signal in a single screening of the slides. This technique has been used for rapid correlation of the genetic and physical map of chromosome 11q13-qter in the region of genes responsible for ataxia-telangiectasia and tuberous sclerosis.

Cell Line↗
PubMed1990

Fluorescence in situ hybridization on metaphase chromosomes with biotinylated probes. In situ hybridization, biotin labeling, cosmids, gene mapping, oncogene amplification.

In situ hybridization on metaphase chromosomes have been used to localize specific nucleic acid sequences. Initially, the nucleic acid probes were labeled isotopically. Over the past few years, non isotopic techniques have considerably progressed, and are being applied to a large spectrum of biological and clinical problems.

Biotin↗
PubMed1989

Detection of single-copy genes by nonisotopic in situ hybridization on human chromosomes.

A technique of in situ hybridization on metaphase chromosomes with biotinylated DNA probes is described. This technique was used to localize unique DNA sequences on chromosomes and allowed a localization of two probes 1.8 and 1.3 kb long. The hybridization signal appears like two, twin, spots on the two sister chromatids, allowing a clear distinction from the background. Moreover a chromosomal localization is possible by counting a relatively small number of mitoses compared with the technique using 3H-labeled DNA probes.

Biotin↗
PubMed1989

Selection of cells with different chromosomal localizations of the amplified c-myc gene during in vivo and in vitro growth of the breast carcinoma cell line SW 613-S.

The c-myc gene is amplified in the human breast carcinoma cell line SW 613-S. At early in vitro passages, the extra copies of the gene were mainly localized in double minute chromosomes (DMs), as shown by in situ hybridization with a biotinylated c-myc probe. However, cells without DMs were also present in which the c-myc genes were found integrated into any of several distinct chromosomes (mainly 7q+, 4 and 4q+, and 1). When this cell line was propagated in vitro, the level of c-myc amplification decreased because cells with DMs and a high amplification level were lost and replaced by cells without DMs and having a low amplification level. On the contrary, when early passage SW 613-S cells were grown in vivo, as subcutaneous tumours in nude mice, cells with numerous DMs and a high level of c-myc amplification were selected for. In one cell line (SW 613-Tu1) established from such a tumour, the DM-containing cells were substituted at late passages for cells with a high number of c-myc copies integrated within an abnormally banded region, at band 17q24 of a 17q+ chromosome. When only cells with integrated genes were present, this cell line was still highly tumorigenic indicating that the localization of the c-myc genes in DMs was not required for these cells to be tumorigenic in nude mice. Furthermore, cells of the secondary tumours induced by SW 613-Tu1 did not contain any DMs showing that in vivo growth did not promote the release of integrated c-myc copies into DMs.

Blotting, Southern↗