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F Galibert

Publications and source records attributed to F Galibert.

At least 127 records · Page 7Linked to original sources
PubMed1989

Nucleotide sequence of HIV1-NDK: a highly cytopathic strain of the human immunodeficiency virus.

A highly cytopathic strain of HIV1, named HIV1-NDK, has been isolated from a Zaïrian patient affected with AIDS. This isolate is 10(4) times more cytopathic and infectious than the prototype. To correlate the high cytopathic properties of this strain with genetic variations, we have cloned and sequenced the genome of this isolate. The principal feature which could be drawn from the fine analysis of the HIV1-NDK sequence is that the variability is not clustered in one particular region but rather spread out all along the genome. Only minor differences seem to be responsible for the acute biological effect of HIV1-NDK.

Amino Acid Sequence↗
PubMed1989

Molecular analysis of glycophorin A and B gene structure and expression in homozygous Miltenberger class V (Mi. V) human erythrocytes.

In the Miltenberger class V (Mi. V) condition, red cells lack glycophorin A (GPA) and glycophorin B (GPB) but carry instead an unusual glycoprotein thought to be a hybrid molecule produced by the unequal crossing-over between the closely linked genes encoding for GPA and GPB. By Western blot analysis with rabbit anti-GPA antibodies specific for discrete domains of GPA, it was found that the Mi. V glycoprotein (donor F. M.) contains approximately 60 amino acid residues of GPA at its N-terminus. As a preliminary approach to the molecular analysis of this variant the restriction maps of the GPA and GPB genes were established by Southern blot analysis of genomic DNA and from genomic clones isolated from a human leukocyte library constructed in lambda EMBL4. The GPA and GPB genes cover about 30 kb of DNA and are organized into seven exons (A-1-A-7) and five exons (B-1-B-5), respectively. In addition to the normal genes, a third gene (named inv), closely resembling the GPA and GPB genes, was also identified. In the homozygous Mi. V individual the normal GPA and GPB genes were absent, but an unusual form of gene structure was detected by Southern blot analysis. The Mi. V glycoprotein gene was composed of exon B-1 of the GPB gene followed by exons A-2 and A-3 of the GPA gene and the exons B-3, B-4 and B-5 of the GPB gene. Exon B-1 can be distinguished from exon A-1 of GPA since it is located within a different restriction fragment, but both encode the same amino acid sequence (N-terminal region of the signal peptides). Using the polymerase chain reaction, the junction between exon A-3 and exon B-3 was confirmed by amplification of the DNA region where the putative crossing-over has occurred and it was deduced that the Mi. V glycoprotein is a hybrid molecule composed of amino acid residues 1-58 from GPA fused to amino acid residues 27-72 of GPB. In addition, the finding that part of the signal peptide and the 5'-untranslated region are derived from GPB suggests that the genetic background of the Mi. V variant is rather complex and may involve a cascade of recombination or gene conversion events.

Amino Acid Sequence↗
PubMed1989

Can ribozymes be used to regulate procaryote gene expression?

The in vivo activity of ribozymes designed against mRNA coding for E. coli beta-galactosidase was tested both in intramolecular and in intermolecular conditions. When recombinant M13 phage DNA carrying on the same molecule the information for both the ribozyme and the target was transfected into bacterial cells, ribozyme activity was observed. Conversely, a ribozyme coded by a recombinant M13 vector, but targeted against an mRNA transcribed from the F episome including the remaining part of the beta-galactosidase gene, was inefficient.

Amino Acid Sequence↗
PubMed1989

Sp alpha I/78: a mutation of the alpha I spectrin domain in a white kindred with HE and HPP phenotypes.

Limited tryptic digestion of spectrin (Sp) from seven related individuals manifesting hereditary elliptocytosis (HE) or hereditary pyropoikilocytosis (HPP) phenotypes revealed the presence of a novel peptide with a molecular weight of 78 Kd and a concomitant decrease in the alpha I domain (80-Kd peptide), which is the domain involved in the dimer self-association process. Sp from the normal members of this white family exhibited a normal peptide pattern, as compared with controls. The abnormal peptide pattern was associated with a decreased ability of Sp dimer to self-associate. In this kindred in which three generations were available for study, the clinical manifestations were quite variable and ranged from the asymptomatic HE carrier state to hemolytic HE or to severe anemia requiring splenectomy. The severity of the disease appeared to be correlated both with the amount of mutant spectrin (31% to 69%) and with the excess of the Sp dimer found in the membrane (26% to 60%, compared with a normal value of 5.6% +/- 2.2%). Partial amino acid sequencing showed that the alpha I/78-Kd peptide resulted from cleavage at lysine residue 10 of the alpha I/80-Kd domain. Knowledge of the exon/intron structure of cloned genomic DNA encoding the alpha I domain allowed us to amplify in vitro a DNA fragment containing the third exon of the alpha-spectrin gene. The amplified fragment was subcloned and sequenced. A G to T transversion was found in the 39th codon (AGT for AGG), which changed the normal arginine to a serine. Hybridization of amplified DNAs with allele-specific oligonucleotides corresponding to the normal and mutant sequences confirmed the presence of the mutation in three other HE members of the family (the propositus mother, brother, and sister).

Adult↗
PubMed1989

Human erythrocyte glycophorin C. Gene structure and rearrangement in genetic variants.

We have previously shown that a deletion of approximately 3 kilobases in the unique glycophorin C (GPC) gene, which encodes for the human erythrocyte glycophorins C and D, is associated with the Gerbich (Ge) blood group deficiency (Ge-2,-3 and Ge-2,+3 types) (Le van Kim, C., Colin, Y., Blanchard, D., Dahr, W., London, J. & Cartron, J.P. (1987) Eur. J. Biochem. 165, 571-579). We have now isolated and characterized the structure of the GPC gene from the common Ge+2,+3 donors and from a Ge-2,-3 variant (Ge-2,-3 gene). The GPC gene is organized in four exons distributed over 13.5-kilobase pairs (kbp) DNA and contains two directly repeated domains of 3.4 kbp in length which are likely derived from the recent duplication of a unique ancestral domain. Restriction mapping and sequence analysis indicate that a 3.4-kbp deletion within this gene, arising probably by unequal crossing over between the two repeated domains, is responsible for the formation of the Ge-2,-3 gene. The breakpoints of the deletion are located within introns 2 and 3, and therefore exon 3 is removed. The defective gene is transcribed as a mRNA with a continuous open reading frame extending over 300 nucleotides which is translated into an unusual sialoglycoprotein present on Ge-2,-3 red cells. The primary structure of this new glycoprotein has been deduced from nucleotide sequencing. It is proposed in addition, that another 3.4-kb deletion within the GPC gene eliminates exon 2 only by a similar mechanism and generates a defective gene encoding for the abnormal glycoprotein present on Ge-2,+3 erythrocytes. Interestingly, the same deletion which lead to the rare Ge-2,-3 genetic condition, occurred spontaneously and frequently in the cloned GPC gene during the propagation of the recombinant phages in Escherichia coli. From these observations we suggest that the Ge-2,-3 and Ge-2,+3 genes might represent the two allelic forms of a unique ancestral form of the GPC gene, following successive internal duplication and deletion events.

Amino Acid Sequence↗
PubMed1989

Expression of the human parvovirus B19 protein fused to protein A in Escherichia coli: recognition by IgM and IgG antibodies in human sera.

A 1.4 kb fragment (nucleotides 2430 to 3901) encoding portions of the human parvovirus B19 structural proteins was inserted into the pRIT2 plasmid expression vector containing the gene encoding staphylococcal Protein A under the control of the phage lambda promoter PR. The fusion protein was used to raise antibodies in rabbits. The sera were shown by immune electron microscopy to agglutinate B19 particles and were also shown to recognize the VP2 B19 capsid protein, by Western blot analysis. The B19 antigenicity of the fusion protein was confirmed by immunoblot and enzyme immunoassay with IgG and IgM anti-B19-positive reference human sera.

Antibodies, Viral↗
PubMed1989

New recA mutations that dissociate the various RecA protein activities in Escherichia coli provide evidence for an additional role for RecA protein in UV mutagenesis.

To isolate strains with new recA mutations that differentially affect RecA protein functions, we mutagenized in vitro the recA gene carried by plasmid mini-F and then introduced the mini-F-recA plasmid into a delta recA host that was lysogenic for prophage phi 80 and carried a lac duplication. By scoring prophage induction and recombination of the lac duplication, we isolated new recA mutations. A strain carrying mutation recA1734 (Arg-243 changed to Leu) was found to be deficient in phi 80 induction but proficient in recombination. The mutation rendered the host not mutable by UV, even in a lexA(Def) background. Yet, the recA1734 host became mutable upon introduction of a plasmid encoding UmuD*, the active carboxyl-terminal fragment of UmuD. Although the recA1734 mutation permits cleavage of lambda and LexA repressors, it renders the host deficient in the cleavage of phi 80 repressor and UmuD protein. Another strain carrying mutation recA1730 (Ser-117 changed to Phe) was found to be proficient in phi 80 induction but deficient in recombination. The recombination defect conferred by the mutation was partly alleviated in a cell devoid of LexA repressor, suggesting that, when amplified, RecA1730 protein is active in recombination. Since LexA protein was poorly cleaved in the recA1730 strain while phage lambda was induced, we conclude that RecA1730 protein cannot specifically mediate LexA protein cleavage. Our results show that the recA1734 and recA1730 mutations differentially affect cleavage of various substrates. The recA1730 mutation prevented UV mutagenesis, even upon introduction into the host of a plasmid encoding UmuD* and was dominant over recA+. With respect to other RecA functions, recA1730 was recessive to recA+. This demonstrates that RecA protein has an additional role in mutagenesis beside mediating the cleavage of LexA and UmuD proteins.

Bacterial Proteins↗
PubMed1989

c-kit mRNA expression in human and murine hematopoietic cell lines.

The c-kit proto-oncogene belongs to the tyrosine kinase receptor family. Although its ligand is still unknown, there is increasing evidence to suggest its involvement in hematopoiesis. In order to detect lineage or differentiation related specificity, we have studied c-kit mRNA expression in both human and murine hematopoietic organs and cell lines. We show that c-kit mRNA expression is found at early stages of erythroid and myeloid differentiation. There is however, no evidence of c-kit expression in the lymphoid lineage. Our results suggest a possible role for c-kit as a receptor in the early stages of the erythroid/myeloid differentiation.

Animals↗
PubMed1989

[Nucleotide mapping and a kinetic model of a heteroplasmic deletion of 4,666 base pairs from mitochondrial DNA in the Kearns-Sayre syndrome].

We report the nucleotidic mapping of a 4,666 base pairs deletion of the human mitochondrial DNA localized at positions 8571 and 13237 in a Kearns-Sayre syndrome patient. The gene fusion between the 15 N terminal amino acid residues of ATP synthetase subunit 6 and the 303 C terminal aminoacids of NADH dehydrogenase yields a potential protein of 35,000 d MW called A6-ND5. Deletion boundaries show a short inverted repeat ATCXTA. The heteroplasmic deletion mechanism is discussed in view of these data.

Amino Acid Sequence↗
PubMed1989

Nucleotide sequence and structural organization of the human FMS proto-oncogene.

The human proto-oncogene c-fms [FMS] on chromosome 5q33.3 encodes a transmembrane glycoprotein with tyrosine kinase activity that functions as the cell surface receptor for the macrophage colony stimulating factor (CSF-1 or M-CSF). Overlapping bacteriophage clones that included 35 kb of the FMS locus and contained the complete coding sequence of the CSF-1 receptor were subjected to nucleotide sequencing analysis. Comparison with the cDNA sequence of the human c-fms gene indicated that at least one 5' noncoding exon is located far upstream (ca. 26 kb) from sequences encoding the CSF-1 receptor. The FMS coding sequence consists of 21 small exons and heterogeneously sized introns, ranging from 6.3 kb to less than 0.1 kb in complexity.

Base Sequence↗
PubMed1989

In vitro amplification of T cell gamma gene rearrangements: a new tool for the assessment of minimal residual disease in acute lymphoblastic leukemias.

In order to improve the level of sensitivity and specificity of detection of bone marrow minimal residual disease in the acute lymphoid leukemias, we have performed amplification by the polymerase chain reaction of T cell receptor gamma chain gene rearrangements. Cloning and sequencing of amplified leukemic DNA allowed the construction of a clone-specific anti-junctional oligonucleotide to be used for subsequent detection of minimal infiltration by this clone. Using such an oligonucleotide, it was possible to distinguish clonal DNA from polyclonal T lymphocytes and to detect infiltration by this clone at 10(-6) dilution into germline DNA. We therefore describe a generally applicable method for the detection of minimal residual disease in both T-ALL and the majority of B lineage ALLs.

Gene Amplification↗
PubMed1989

The use of clone-specific anti-VJ junction oligonucleotides to identify minor clonal lymphoid populations.

The polymerase chain reaction was used to amplify rearrangements of T-cell receptor gamma genes from 2 leukemic DNA samples involving the same variable segment. One V-J junction was sequenced and an anti-junctional oligonucleotide synthesized. This oligonucleotide was used as probe on in vitro amplified DNA. We show that this strategy allows the detection of the corresponding clonal DNA at dilutions of up to 10(6) fold in germline DNA. Moreover we demonstrate that it is possible to differentiate this clone from the second leukemic clone and from polyclonal T-cells.

Burkitt Lymphoma↗
PubMed1989

In vitro growth properties and PCR ras gene analysis of a murine embryonal carcinoma cell line harboring an amplified c-Ki-ras gene.

Ras proto-oncogenes are thought to be involved in both proliferation and malignant processes. We examined some growth properties of a murine embryonal carcinoma cell line (ECC), PCC4, that have been shown previously to be amplified for the c-KI-ras gene. Our results show that doubling time and plating efficiency are not significantly affected by such amplification. To examine the possible link between malignant behavior and c-Ki-ras alteration, we investigated activating mutations in this PCC4 cell line as well as in other ECC. Analysis of the in vitro amplified Ki-ras gene by PCR technology has not revealed point mutations in any of the ECC examined.

Animals↗
PubMed1988

Cloning and expression of a cDNA for human thioredoxin.

Thioredoxin is the best representative enzyme of a group of proteins, widely distributed and possessing dithiol-disulfide oxidoreductase activity. We have constructed a cDNA library from messenger RNAs isolated from a lymphoblastoid B cell line (Epstein-Barr virus-immortalized normal human lymphocytes). Screening of this library with synthetic oligonucleotide probes, constructed from the NH2-terminal amino acid sequence of a protein produced by this line, allowed us to identify a full-length cDNA clone coding for human thioredoxin. The open reading frame (315 nucleotides long) codes for a protein of 104 amino acids (excluding the initial methionine). This protein possesses the highly conserved enzymatic active site common to plant and bacterial thioredoxins: Trp-Cys-Gly-Pro-Cys (amino acids 30-34). These data provide for the first time the complete primary sequence of a thioredoxin of mammalian origin. Recombinant human thioredoxin, expressed in Escherichia coli, possesses a dithiol-reducing enzymatic activity as assayed on mammalian and plant substrates. It is able to reduce the interchain disulfide bridges of murine pentameric IgM and porcin insulin and also to activate vegetal NADP-malate dehydrogenase. Studies of human thioredoxin mRNA expression and regulation in immunocompetent cells of human origin indicate that the protein is weakly expressed in resting lymphocytes and monocytes, but the level of human thioredoxin mRNA transcription is quite important in activated monocytes and established dividing human cell lines.

Amino Acid Sequence↗
PubMed1988

Primary structure and functional organization of Drosophila 1731 retrotransposon.

We have determined the nucleotide sequence of the Drosophila retrotransposon 1731. 1731 is 4648 bp long and is flanked by 336 bp terminal repeats (LTRs) previously described as being reminiscent of provirus LTRs. The 1731 genome consists of two long open reading frames (ORFs 1 and 2) which slightly overlap each other. The ORF 1 and 2 present similarities with retroviral gag and pol genes respectively as shown by computer analysis. The pol gene exhibits several enzymatic activities in the following order: protease, endonuclease and reverse transcriptase. It is possible that 1731 also encompasses a ribonuclease H activity located between the endonuclease and reverse transcriptase domains. Moreover, comparison of the 1731 pol gene with the pol region of copia shows similarities extending over the protease, endonuclease and reverse transcriptase domains. We show that codon usage in the two retrotransposons is different. Finally, no ORF able to encode an env gene is detected in 1731.

Animals↗
PubMed1988

Viruslike particles containing knob-associated histidine-rich protein are secreted into the culture medium of Plasmodium falciparum in vitro cultures.

This report describes the isolation of a viruslike particle from in vitro cultures of the human malaria parasite P. falciparum. Electronmicroscopic observations suggest that the particles are liberated into the culture medium by budding from the erythrocyte membrane. The density of the free particles is 1.16, they contain nucleic acid and two distinct molecular species of the knob-associated Histidine-rich protein. Proteins of the particles are recognized by sera from malaria patients. The previously described knobs may correspond to viral coats inserted in the membrane.

Animals↗