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F Apiou

Publications and source records attributed to F Apiou.

At least 37 records · Page 2Linked to original sources
PubMed1996

The human interleukin-11 receptor alpha gene (IL11RA): genomic organization and chromosome mapping.

The high-affinity receptor for interleukin-11 (IL-11) is composed of two subunits, IL-11 receptor alpha chain (IL-11R alpha) and gp130, the common subunit of the interleukin-6 (IL-6), ciliary neurotrophic factor (CNTF), leukemia inhibitory factor, and oncostatin M receptors. The IL-11 receptor-specific alpha chain shares homologies with the alpha chain of the CNTF and IL-6 receptors. We isolated and characterized genomic DNA clones encompassing the entire coding sequence of the IL-11R alpha cDNA. The exon-intron organization of the IL-11R gene (HGMW-approved symbol IL11RA) is consistent with the predicted structure of the different domains of the IL-11R alpha protein, confirming evolutionary conservation at the level of gene organization among the hematopoietic cytokine receptor family. The IL-11R gene has been assigned to chromosome 9 band p13 by in situ hybridization using human IL-11R alpha cDNA as a probe. The fact that the ciliary neurotrophic factor (CNTFR) gene has recently been localized on this same band and the conserved genomic structure between IL-11R and CNTFR suggest that they may have evolved from a common ancestor.

Base Sequence↗
PubMed1996

Molecular cloning, functional expression, pharmacological characterization and chromosomal localization of the human metabotropic glutamate receptor type 3.

Glutamic acid is the major excitatory amino acid of the central nervous system which interacts with two receptor families, the ionotropic and metabotropic glutamate receptors. The metabotropic glutamate receptors (mGluRs) are coupled to G proteins and can be divided into three subgroups based on their sequence homology, signal transduction pathway and pharmacology. In this study, we describe the cloning of the cDNA encoding the human metabotropic glutamate receptor type 3 (HmGluR3). It was obtained by reverse transcription-polymerase chain reaction (RT-PCR) with degenerate oligonucleotides corresponding to highly conserved sequences between rat mGluRs. The receptor shows 879 amino acids with 96% amino acid sequence identity with rat mGluR3. It is strongly expressed in fetal and adult whole brain, especially in caudate nucleus and corpus callosum. The gene was identified by fluorescence in situ hybridization on chromosome 7 band q22. Activation of the human mGluR3, permanently expressed in Baby Hamster Kidney (BHK) cells, by excitatory amino acid inhibits the forskolin-stimulated accumulation of intracellular cAMP. The rank order of potency is L-glutamic acid > or = (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R)-ACPD) >> ibotenic acid > quisqualic acid. (RS)-alpha-methyl-4-carboxyphenylglycine [(RS)-MCPG, 1 mM] is without effect on inhibition of forskolin-induced cAMP accumulation by L-glutamic acid.

Amino Acid Sequence↗
PubMed1996

Structural heterogeneity of hsr(11) in the MDA-MB-134 mammary carcinoma cell line.

The MDA-MB-134 cell line was characterized by the presence of two homogeneously staining region (hsr) carrier chromosomes containing sequences from 8p11-p12, 11q13, and 8q24. Using fluorescence in situ hybridization, a detailed study of the organization of this chromosome has been performed. The hsr carrier chromosomes are shown to be identical and to derive from a chromosome 11, on which large segments of the long arm of chromosome 8 are translocated, forming its short arm. The hsr segment is inserted in the long arm, distally to C1NH gene. It is formed by sequences from both chromosomes 8 and 11. For the genes investigated by both methods the number of copies detected by in situ hybridization is compatible with that expected by quantification of Southern blots. In spite of its complexity, a possible mechanism of formation is proposed.

Breast Neoplasms↗
PubMed1996

High glycolysis in gliomas despite low hexokinase transcription and activity correlated to chromosome 10 loss.

Loss of chromosome 10 was observed in 10 out of 12 xenografted glioblastomas studied. Chromosome 10 carries the gene coding the hexokinase type 1 isoenzyme (HK-I), which catalyses the first step of glycolysis, which is essential in brain tissue and glioblastomas. We investigated the relationships between the relative chromosome 10 number, the amount of HK-I mRNA, HK-I activity and its intracellular distribution, and glycolysis-related parameters such as the lactate-pyruvate ratio, lactate dehydrogenase (LDH) and ATP contents. Individual tumour HK-I mRNA amounts were 23-65% lower than that of normal human brain and reflected the relative decrease of chromosome 10 number (alpha < 0.01). Total HK activities of individual glioblastomas varied considerably but were constantly (a mean of seven times) lower than that of normal brain tissue. The mitochondria-bound HK-I fraction of individual tumours was generally over 50%, compared with that of normal brain tissue. As shown by lactate - pyruvate ratios, in all the gliomas, glycolysis was elevated to an average of 3-fold that measured in normal brain. An elevated ATP content was also constantly noted. Adaptation of glioblastoma metabolism to the chromosome 10 loss and to the HK-I transcription unit emphasises the critical role of glycolysis in their survival. We hypothesise that HK-I, the enzyme responsible for initiating glycolysis necessary for brain function, may approach its lowest limit in gliomas, thereby opening therapeutic access to pharmacological anti-metabolites affecting energy metabolism and tumour growth.

Adenosine Triphosphate↗
PubMed1996

Constitutive amplification of a zinc finger protein gene in cattle.

The human OZF gene encodes a protein consisting essentially of zinc finger motifs of the Krüppel type. Evolutionary studies revealed amplification of the bovine OZF gene in cattle. Domestic cattle includes two major subspecies: taurine (Bos primigenius taurus) and zebu (B. p. indicus). Amplified sequences were found in both subspecies and mapped to the same locus of chromosome X in band q11. No amplification was found in other bovids and in particular in Bison, the closest related genus to the genus Bos. One copy of the amplified locus was cloned and sequenced. It encodes a protein sharing 95% identity with the human OZF protein. The bovine OZF gene was detected in an additional locus on chromosome 18 in both Bos and Bison, in band q23-24, which is likely to represent the ancestral position of the OZF gene. This is the first evidence of gene amplification in a mammalian species during evolution.

Amino Acid Sequence↗
PubMed1996

Demonstration of homoeologies between human and lemur chromosomes by chromosome painting.

Human-specific probes for chromosomes 3, 7, 9, 14, 19, and 21 were used to paint chromosomes of three lemur species: Eulemur fulvus mayottensis, E. macaco macaco, and Lemur catta. Chromosomes 1 and 3 of E. f. mayottensis are homoeologous to human chromosomes 3, 9, 14, and 21, as previously suggested by chromosome banding. Probes for human chromosomes 7 and 19 produced unexpectedly strong signals in the centromeric regions of all lemur chromosomes, suggesting that sequences homologous to nonrepeated sequences of the human genome have been amplified during the formation of constitutive heterochromatin in lemurs.

Animals↗
PubMed1996

Fine mapping of human HOX gene clusters.

The chromosome localization of human HOX gene clusters has been reinvestigated by fluorescence in situ hybridization (FISH). Three loci were precisely localized in 7p15.3 (HOXA@), 17q21.3 (HOXB@) and 12q13.3 (HOXC@). The localization of HOXD@ was confirmed to 2q31.

Cells, Cultured↗
PubMed1995

Loss of chromosome 3p arm differentiating tumorigenic from non-tumorigenic cells derived from the same SV40-transformed human mammary epithelial cells.

After immortalization of human normal mammary epithelial cells by replication-defective SV40 genome integration, 2 cultures were developed independently. Both had the same integration site, in band 9q21, but rapidly diverged karyotypically. After a few passages, one, designated SC2T2, exhibited near-diploid (a) and the other, designated SL2T2, near-tetraploid (b) karyotypes. The simplest formulas were 44, X, -X, der(3;22) (q10;q10), der(4) t(4;9)(q34;q12), +8, +9, add(13)(p1), der(19) t(8;19)(q21;p13.3), add(22)(p1) for karyotype (a) and 93, XXXX, add(1)(q12), add(11)(q13), +20 for karyotype (b). A number of alterations were further acquired with passages. Both cell cultures were tumorigenic, but their efficiency of grafting in nude mice largely differed: it was low for SL2T2 and high for SC2T2 cultures. All cultures of the xenografted tumors, obtained from either SL2T2 or SC2T2, exhibited the same clonal anomalies as those characterizing karyotype (a). It was concluded that only cells with karyotype (a) were tumorigenic, and that the difference in the tumorigenic potential of cultures SC2T2 and SL2T2 was related to their richness in cells with this karyotype. The comparison of the various karyotypes, together with data obtained in other cell types transformed by SV40, suggests that the acquisition of tumorigenicity in S2T2 mammary epithelial cells may be related to the loss of chromosome 3p arm.

Breast Neoplasms↗
PubMed1995

Integration of viral sequences into the c-myc gene in two mammary adenocarcinomas induced by polyomavirus in athymic nude mice.

We report the analysis of polyomavirus (Py) DNA integration into chromosomal DNA of two Py-induced mammary adenocarcinomas of athymic nude mice. Prior observations had established that these tumors had high levels of episomal Py DNA, making analysis of integration sites difficult. Propagation of tumor cells in culture allows the isolation of lines which have lost episomal Py DNA but are still tumorigenic and thus can be used for in situ and Southern analysis of Py sequences. The data reported here support the conclusion that Py DNA integrated into and next to the c-myc gene, adding further importance to this tumor system which, in its modifications of c-myc expression, appears to be similar to some human mammary cancers. In situ hybridization experiments on metaphase chromosomes of tumor cells showed that (i) in both cases, there was a single integration site at the same position on the same chromosome in all cells of a given tumor, and (ii) integration sites were different in the two tumors; in one, it was located on chromosome 15, near the c-myc proto-oncogene, and in the other, it was situated in the distal part of chromosome 1. We have demonstrated a probable rearrangement between chromosome 1 and chromosome 15, in the region of Py insertion, thus suggesting that a specific site on chromosome 15 is involved in tumorigenesis. The discovery that Py DNA was integrated at specific sites in host chromosomes raised the questions of whether such integrations were correlated with the activation of specific oncogenes. The rearrangements of the c-myc proto-oncogene observed on Southern blot analysis for both tumors, along with similar integration patterns of Py sequences, the overexpression of the c-myc gene, and the synthesis of abnormal oversized hybrid transcripts between c-myc and Py genes, favor this hypothesis. Finally, the analysis of episomal Py DNA in various tumors shows viral populations presenting a specific deletion in a part of the Py late region. This deleted region in the episomal virus genome was systematically found integrated in chromosomal DNA, thus arguing for the importance of Py integration in the induction of mammary tumor.

Adenocarcinoma↗
PubMed1995

Partial nucleotide sequence and chromosomal localization of a bovine zinc finger gene ZNF164.

A clone carrying an open reading frame coding for a novel zinc finger protein of the Krüppel family was isolated from a bovine genomic library and designated ZNF 164 (zinc finger protein 164). Partial sequencing revealed that it contained at least 13 zinc finger motifs preceded by a lysine-rich region of 60 amino acids. The ZNF164 protein shared approximately 60% similarity with several zinc finger proteins but did not appear to be orthologous with a previously identified gene. Using fluorescence in situ hybridization, the ZNF164 gene was mapped to bovine chromosome band 17q24.

Amino Acid Sequence↗
PubMed1994

Evidence for long-range oncogene activation by hepadnavirus insertion.

Insertional mutagenesis of host genes, a common oncogenic strategy of slow transforming retroviruses, has recently been described for a DNA virus of the hepadnavirus group: the woodchuck hepatitis virus. This virus causes insertional activation of myc genes, mainly the intronless N-myc2 oncogene, in > 50% of woodchuck liver tumours. In most remaining tumours, N-myc2 is overexpressed without any apparent genetic alteration. To elucidate the role of the virus in such cases, we have cloned and analysed single integration sites in four woodchuck tumours carrying wild-type myc alleles. All sites were clustered within < 20 kb in a single locus, in which scarce unique sequences showed no detectable transcriptional activity. By fluorescent in situ hybridization, N-myc2 and the new locus (win) were localized to the same region of the long arm of the woodchuck X chromosome, and a 150-180 kb intervening distance was deduced from pulse-field gel analysis. The detection of viral integrations in win in additional tumours that produced abundant N-myc2 transcripts further substantiates the link between these two loci in woodchuck tumorigenesis. We propose that efficient activation of the N-myc2 promoter by the hepadnavirus enhancer acting over a long distance might operate in liver cell transformation.

Animals↗
PubMed1994

Putative oncogenic role of the erythropoietin receptor in murine and human erythroleukemia cells.

To determine whether the erythropoietin receptor (Epo-R) plays a role in the course of malignant erythropoietic disorders, this gene was studied in murine and human erythroleukemia cells. An altered Epo-R gene was found in a murine Friend erythroleukemia cell line, FCL1, due to a spleen focus-forming virus (SFFV) long terminal repeat insertion within the noncoding region of the first exon, leading to Epo-R mRNA overexpression. A similar mechanism of Epo-R activation has previously been described in the T3CL-2 Friend erythroleukemia cell line. An elevated number of Epo-binding sites has been observed in two human erythroleukemia cell lines, TF-1 and UT7. In UT7 cells, homogeneously staining region of the short arm of chromosome 19 [hsr (19)] was evidenced, which contained an amplification of the Epo-R gene. This Epo-R gene amplification was confirmed by the quantification of Southern blots in which the intensity of the Epo-R signal was compared in UT7 DNA and in DNA from normal cells. The Epo-R gene was present in UT7 at a mean number of seven to eight copies per cell. Interestingly, the Epo-R gene was rearranged; the breakpoint region was located near the 3' end of the gene, 3 kb downstream from the end of the last exon. Taken together, these results suggest that, in both murine and human systems, genetic alterations of the Epo-R gene are not rare events and could be involved in the occurrence of the erythroleukemic process.

Animals↗
PubMed1994

The OZF gene encodes a protein consisting essentially of zinc finger motifs.

A novel member of the zinc finger Krüppel family was isolated as a cDNA clone from the human mammary cell line HBL100. It contains an open reading frame consisting of 32 amino acid residues followed by ten zinc finger motifs and was accordingly named OZF (Only Zinc Fingers). Assuming that translation initiation starts at the unique methionine codon, 22 codons downstream of the beginning of the open reading frame as suggested by in vitro translation of OZF mRNA, the OZF protein is 292 residues long and has an estimated molecular mass of 33 kDa. The OZF gene is located in band q13.1 of the long arm of human chromosome 19. It is expressed as a single mRNA in liver, skeletal muscle and mammary cells and as two mRNA species in heart muscle. Absent or very low levels of expression were observed in brain, lung, placenta, kidney and human fibroblasts in culture. Thus, the OZF protein, which consists essentially of a DNA/RNA binding domain, may act as a tissue-specific modulator of gene expression.

Amino Acid Sequence↗
PubMed1994

Organization and chromosomal assignment of two human PAG gene loci: PAGA encoding a functional gene and PAGB a processed pseudogene.

A cDNA, designated PAG, was recently isolated by differential cloning between an untransformed and a ras-transformed human mammary cell line. Higher levels of expression were found to be associated with cell proliferation. The absence in the pag protein of known consensus sequence, as well as its close relationship with a gene product involved in the differentiation of a mouse erythroleukemia cell line, has suggested that the PAG gene belongs to a family of genes associated with cell proliferation and differentiation. To further characterize this gene, a physical map has been established from a human genomic cosmid library. The PAG gene spans 13 kb of DNA and contains six exons. The promoter region is GC-rich and contains a TFIID motif located 25 nucleotides upstream of the potential site for initiation of transcription and potential recognition sites for a variety of trans-acting factors. Using fluorescence in situ hybridization, the PAG gene was mapped to human chromosome band 1p34.1. A pseudogene was also isolated, sequenced, and mapped to human chromosome band 9p22.

Base Sequence↗
PubMed1994

Chromosomal localization and sequence analysis of a human episomal sequence with in vitro differentiating activity.

The genomic fragment carrying the human activator of liver function, previously described as an episome capable of inducing differentiation upon transfection into a dedifferentiated rat hepatoma cell line, was mapped on human chromosome 12q24.2-12q24.3. This chromosomal location was indistinguishable by in situ hybridization from that of the gene coding for the hepatic transcription factor HNF1. The sequence of the integrated form of the episome as well as its flanking sequences show that it is rich in retroposons. It contains a human ribosomal protein L21 processed pseudogene, one truncated L1Hs sequence, and 10 Alu repeats, which belong to different subfamilies.

Adult↗
PubMed1994

Mapping of 18 probes on human chromosome 18 using single- and double-color FISH.

Fluorescence in situ hybridization (FISH) techniques were applied to the mapping of 18 probes from chromosome 18, permitting seven new assignments: D18S16 (18p11.31), D18S12 (18p11.1), D18S1 (18q12.2), D18S13 (18q21.31), D18S18 (18q21.31), D18S14 (18q21.33), and D18S17 (18q23). In addition, the localization of D18S3 in 18p11.3 was confirmed and that of D18S6, previously mapped in 18p11, was changed to 18q21.13. Finally, a more accurate mapping for nine probes was proposed: D18S7 (18q12.2), D18S10 (18q12.2), D18S24 (18q21.13), D18S8 (18q21.13), GRP (18q21.31), BCL2 (18q21.33), D18S5 (18q22.1), D18S19 (18q22.1), and D18S11 (18q22.3). The ordering of probes located in close proximity was made possible by combined use of single-color FISH with direct assignment on banded chromosomes, chromosomal length measurements, and double-color FISH.

Chromosome Mapping↗