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Biomedical subjects

F Galibert

Publications and source records attributed to F Galibert.

At least 163 records · Page 9Linked to original sources
PubMed1986

Isolation of cDNA clones and complete amino acid sequence of human erythrocyte glycophorin C.

Two cDNA clones for glycophorin C, a transmembrane glycoprotein of the human erythrocyte which carries the blood group Gerbich antigens, have been isolated from a human reticulocyte cDNA library. The clones were identified with a mixture of 32 oligonucleotide probes (14-mer) which have been synthetized according to the amino acid sequence Asp-Pro-Gly-Met-Ala present in the N-terminal tryptic peptide of the molecule. The primary structure of glycophorin C deduced from the nucleotide sequence of the 460 base-pair insert of the pGCW5 clone indicates that the complete protein is a single polypeptide chain of 128 amino acids clearly organized in three distinct domains. The N-terminal part (residues 1-57, approximately) which is N- and O-glycosylated is connected to a hydrophilic C-terminal domain (residues 82-128, approximately) containing 4 tyrosine residues by a hydrophobic stretch of nonpolar amino acids (residues 58-81, approximately) probably interacting with the membrane lipids and permitting the whole molecule to span the lipid bilayer. Northern blot analysis using a 265-base-pair restriction fragment obtained by DdeI digestion of the inserted DNA shows that the glycophorin C mRNA from human erythroblasts is approximately 1.4 kilobases long and is present in the human fetal liver and the human K562 and HEL cell lines which exhibit erythroid features. The glycophorin C mRNA, however, is absent from adult liver and lymphocytes, indicating that this protein represents a new erythrocyte-specific probe which might be useful to study erythroid differentiation.

Amino Acid Sequence↗
PubMed1986

Immunochemical detection of proteins related to the human c-myc exon 1.

Published sequence data of the human c-myc gene indicate the presence of a coding capacity for a polypeptide of 188 residues within the first exon. Using antibodies raised against five synthetic peptides corresponding to different non-over-lapping parts of this polypeptide, two proteins of 32 kd and 58 kd antigenically related to the synthetic peptides have been detected in extracts of human cells. The confidence of this detection has been reinforced by showing that epitopes corresponding to different peptides were indeed located on the same molecule and that the 58 kd protein appears to be a dimeric form of the 32 kd protein. That these proteins originate from the first exon was indicated by: hybrid-arrested translation experiments followed by immunodetection of the translation products; in vitro translation of messenger RNA derived from cloned exon 1 by SP6 polymerase transcription.

Amino Acid Sequence↗
PubMed1986

Restriction fragment length polymorphism caused by a deletion within the human c-abl gene (ABL).

A restriction fragment length polymorphism at the human c-abl locus (ABL) has been detected in 67 unrelated individuals by agarose gel electrophoresis and Southern blot hybridization using 32P-labeled v-abl probes. This polymorphism is generated by the existence of two alleles, a and b, which are in Hardy-Weinberg equilibrium, with frequencies of 94.8% and 5.2%, respectively. The minor allele, b, is due to a deletion of about 500 base pairs in an intron located downstream of the codon for the phosphate-acceptor tyrosine residue of the c-abl gene product.

Alleles↗
PubMed1986

Analysis of integrated proviral DNA sequences with an octadecanucleotide probe designed for specific identification of spleen focus-forming virus in the mouse genome.

The Friend spleen focus-forming virus (SFFV) is an envelope gene recombinant between the ecotropic Friend murine leukemia virus and the endogenous xenotropic mink cell focus-forming retroviral sequences. We synthesized an octadecanucleotide complementary to the 3' end of the SFFV env gene designed for discriminating the SFFV proviruses from the xenotropic mink cell focus-forming virus and ecotropic exogenous or endogenous viral sequences. Under appropriate hybridization conditions this probe allowed the identification, in addition to few endogenous DNA fragments, of multiple SFFV proviruses integrated in the genome of Friend malignant cells. Therefore this probe should be of interest in further characterizing the SFFV integration sites and possibly the SFFV ancestor gene.

Animals↗
PubMed1985

Molecular cloning and nucleotide sequence of a cDNA clone coding for rat brain myelin proteolipid.

A cDNA library from rat brain was constructed in pBR322 and screened with a 14-mer mixed oligonucleotide probe based on residues 231-235 of bovine proteolipid (PLP). A positive clone was isolated: it contained a 1334-base-pair cDNA insert and was subjected to DNA sequence analysis. The cDNA encoded information for the 276 amino acids of rat PLP. Comparison with bovine PLP sequence showed a complete amino acid sequence homology except for 4 amino acid residues.

Animals↗
PubMed1985

The HBV HBX gene expressed in E. coli is recognised by sera from hepatitis patients.

We have cloned the X gene (HBx) and the HBc antigen (HBc Ag) gene of human hepatitis B virus (HBV) in Escherichia coli as fusion products with beta-galactosidase. Both HBV genes are expressed in E. coli strain CSR 603. Expression is detected by u.v. irradiation of the bacteria, metabolic labelling and electrophoresis of the labelled extracts on SDS-polyacrylamide gels. The HBc Ag protein produced in bacteria can be recognised by anti-HBc sera and peptides derived from the protein are also recognised by anti-HBe sera. The HBx protein is recognised by some, but not all, sera which are anti-HBe positive. HBx Ag is also recognised by a woodchuck antibody similar to anti-HBe (anti-WHe). These results constitute the first proof that the open reading frame X is a true viral gene and is expressed during HBV (and WHV) infection and that an HBx/anti-HBx system, which may have important biological implications, can exist in parallel with the classic HBe/anti-HBe system.

Animals↗
PubMed1985

An EcoRI restriction fragment length polymorphism (RFLP) in the human c-erb A locus.

An EcoRI restriction fragment length polymorphism (RFLP) was detected in the 3' end of the locus of the c-erb-A proto-oncogene. The frequency of the rarer allele was around 3.0% in a normal population of 107 unrelated individuals. This frequency did not significantly differ in DNA samples from patients with breast tumors or acute leukemias.

Alpharetrovirus↗
PubMed1985

Restriction fragment length polymorphism of the human c-fms gene.

By using blot hybridization with a v-fms probe, a polymorphism for EcoRI, HindIII, and BamHI restriction endonuclease sites associated with the human c-fms locus was observed in a random adult population. This restriction fragment length polymorphism can be explained on the basis of the existence of two alleles, a and b, and is due to a short (congruent to 500 base pairs) deletion characteristic of allele a. The distribution in the analyzed population (48 unrelated individuals) is 23% heterozygotes ab, 75% homozygotes bb, and 2% homozygotes aa. Though the inheritance of this polymorphism follows a Mendelian pattern, the children from couples ab X bb are of the following genotype: 74% ab and 26% bb. These deviations from the expected frequencies of 50% suggest a selective pressure in favor of heterozygotes.

Alleles↗
PubMed1985

The interferon compartment of the immune response in human malaria: I. Interferon inducers in Plasmodium falciparum cultures.

The present study concerns the interferon (IFN) compartment of the immune response in human malaria. It was undertaken with Plasmodium falciparum parasitized human red blood cell culture supernatants (PF-RBCS). Investigations were conducted in order to verify whether supernatants of such protozoa cultures had the capacity to induce gamma interferon previously identified in sera of P. falciparum infected patients and to verify whether a T-cell mitogen recently characterized in vitro could be correlated with the eventual IFN-inducing activity. Investigations were performed with nonsynchronized P. falciparum cultures and highly synchronized PF-RBC cycles. Results obtained with the first type of experiment demonstrated the presence of an immune interferon inductor in PF-RBCS controlled for their positive mitogenic activity. In supernatants from highly synchronized PF-RBC cycles it was possible to further correlate the mitogen activity with the capacity to induce IFN-gamma. Both activities were found in the time-interval situated near the end of the parasite cycle shortly previous of the merozoite stage. At an earlier time, at the peak of the ring stage, when no mitogen activity was detected, an interferon-induction activity, solely of IFN-alpha, was also demonstrated.

Cells, Cultured↗
PubMed1984

Organization and expression of the E4 region of adenovirus 2.

The E4 region of Adenovirus 2 is a leftward transcribed part of the viral genome. Its nucleotide sequence has already been analysed. From this sequence several open reading frames were defined, which could be used in the coding of the E4 proteins. Using S1 digestion of mRNA-DNA hybrids a precise mapping of donor and acceptor sites was done. Their use in various combinations allows the synthesis of mRNAs, able to direct the synthesis of at least 7 polypeptides, ranging in size from 9K to 34K. Comparison of the sequences of the different acceptor sites indicates that they all conform to the consensus sequence. Analysis of the ATG surrounding sequence shows that initiator ATG may be positively selected according to Kozak's rule.

Adenoviruses, Human↗
PubMed1984

Nucleotide sequence of the human c-myc locus: provocative open reading frame within the first exon.

The nucleotide sequence of a HindIII-EcoRI DNA fragment, 8 kbp long, of a lambda recombinant containing the whole human c-myc gene has been deduced by the method of Maxam and Gilbert. This fragment encodes the complex c-myc locus and the sequence provides information relative to the 2.7 kb long c-myc transcript. It appears that although exons 2 and 3 would code for a 48-K protein homologous to the myc domain of the viral p110 gag-myc protein, the first exon, which has a large open reading frame ending with a stop codon just upstream from the donor splice site, could code on its own for a 20-K protein. Speculations about the role of that putative protein on the regulation of the expression of exons 2 and 3 are made.

Base Sequence↗
PubMed1984

The second oncogene mil of avian retrovirus MH2 is related to the src gene family.

The nucleotide sequence of a PstI fragment prepared from a cloned MH2 virus genome, pMH2-Hd, has been deduced using chemical and enzymatic methods. This fragment, 1862 nucleotides in length, starts with the gag gene, encodes the v-mil sequence and stops within the v-myc gene. This sequence shows that the v-mil gene is fused to the gag gene giving rise to a fused polyprotein of 98 000 daltons: 515 amino acids at the amino terminus would correspond to p10, p19, p27 and part of p12 determinants, 347 amino acids at the carboxy terminus correspond to the v-mil specific sequence. The mil protein shares homology with a number of onc proteins such as src, fes, fms, mos, yes, fps and erbB, as well as with the catalytic chain of the cAMP-dependent protein kinase. This PstI fragment also encodes the beginning of the myc gene which was integrated in MH2 along with the 3' end of the preceding intron placing an acceptor splice site in front of the used open reading frame. As deduced from the sequence, the MH2 myc protein is not identical to the MC29 myc protein. It differs at its amino terminus, which contains little or no gag determinants, depending on the ATG used to initiate translation.

Amino Acid Sequence↗
PubMed1984

Nucleotide sequence of the feline retroviral oncogene v-fms shows unexpected homology with oncogenes encoding tyrosine-specific protein kinases.

The nucleotide sequence encoding the transforming polyprotein of the McDonough strain of feline sarcoma virus was determined. This sequence includes 231 nucleotides specifying a leader peptide, 1,377 nucleotides encoding most of the feline leukemia virus-derived gag gene, and 2,969 nucleotides representing the viral transforming gene v-fms. A single open reading frame was predicted to encode a fusion polyprotein of 160,000 daltons (P160gag-fms). Fourteen potential sites for glycosylation were predicted within the v-fms-encoded portion of the protein, consistent with previous observations that the primary translation product is rapidly glycosylated. The presence of hydrophobic signal peptides within the amino-terminal leader sequence and in the middle of the v-fms-encoded moiety suggests that the transforming glycoprotein becomes oriented with its amino terminus within the lumen of the rough endoplasmic reticulum and its carboxyl terminus protruding across the membrane of the rough endoplasmic reticulum into the cytoplasm. The latter portion of the protein shows unexpected homology to tyrosine-specific protein kinases encoded by several of the known retroviral oncogenes.

Amino Acid Sequence↗
PubMed1984

Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison with woodchuck and human hepatitis B virus sequences.

The nucleotide sequence of an EcoRI duck hepatitis B virus (DHBV) clone was elucidated by using the Maxam and Gilbert method. This sequence, which is 3,021 nucleotides long, was compared with the two previously analyzed hepatitis B-like viruses (human and woodchuck). From this comparison, it was shown that DHBV is derived from an ancestor common to the two others but has a slightly different genomic organization. There was no intergenic region between genes 5 and 8, which were fused into a single open reading frame in DHBV. Genes for the surface and core proteins were assigned to open reading frames 7 and 5/8. Amino acid comparisons showed some structural relationship between gene 6 product and avian reverse transcriptase, suggesting either evolution from a common ancestor or convergence to some particular structure to fulfill a specific function. This should be correlated with the synthesis of an RNA intermediate during DNA replication. This is also taken as an argument in favor of the hypothesis that gene 6 codes for the DNA polymerase that is found within the virion. DNA sequence comparison also showed that the two mammalian hepatitis B viruses are more homologous to each other than they are to DHBV, indicating that DHBV starts to evolve on its own earlier than the two other viruses, as do birds compared with mammals. From this it is proposed that the viruses evolved in a fashion parallel to the species they infect.

Amino Acid Sequence↗
PubMed1984

Nucleotide sequence of the gag gene and gag-pol junction of feline leukemia virus.

The nucleotide sequence of the gag gene of feline leukemia virus and its flanking sequences were determined and compared with the corresponding sequences of two strains of feline sarcoma virus and with that of the Moloney strain of murine leukemia virus. A high degree of nucleotide sequence homology between the feline leukemia virus and murine leukemia virus gag genes was observed, suggesting that retroviruses of domestic cats and laboratory mice have a common, proximal evolutionary progenitor. The predicted structure of the complete feline leukemia virus gag gene precursor suggests that the translation of nonglycosylated and glycosylated gag gene polypeptides is initiated at two different AUG codons. These initiator codons fall in the same reading frame and are separated by a 222-base-pair segment which encodes an amino terminal signal peptide. The nucleotide sequence predicts the order of amino acids in each of the individual gag-coded proteins (p15, p12, p30, p10), all of which derive from the gag gene precursor. Stable stem-and-loop secondary structures are proposed for two regions of viral RNA. The first falls within sequences at the 5' end of the viral genome, together with adjacent palindromic sequences which may play a role in dimer linkage of RNA subunits. The second includes coding sequences at the gag-pol junction and is proposed to be involved in translation of the pol gene product. Sequence analysis of the latter region shows that the gag and pol genes are translated in different reading frames. Classical consensus splice donor and acceptor sequences could not be localized to regions which would permit synthesis of the expected gag-pol precursor protein. Alternatively, we suggest that the pol gene product (RNA-dependent DNA polymerase) could be translated by a frameshift suppressing mechanism which could involve cleavage modification of stems and loops in a manner similar to that observed in tRNA processing.

Amino Acid Sequence↗
PubMed1983

Biochemical and genetical characterization of a fiber-defective temperature-sensitive mutant of type 2 adenovirus.

The adenovirus type 2 fiber mutant H2 ts 125 synthesized an unstable, temperature-sensitive fiber polypeptide with an apparent mol. wt. smaller by 2500 than the wild-type (62 K). The polypeptide of 59.5 K was found to be stable at the permissive temperature (33 degrees C). H2 ts 125 fiber synthesized in reticulocyte lysates had the same apparent mol. wt. of 59.5 K as the mutant fiber produced in vivo. Neither structural nor functional differences between wild-type and mutant fibers were detected in the N-terminal and C-terminal sequences, excluding the occurrence of a new initiation or termination codon. Restriction analysis of H2 ts 125 DNA also ruled out the hypothesis of a deletion mutant. The 59.5 K mutant fiber unit was normally glycosyated, N-acetylated, assembled into 6S oligomeric fiber and incorporated into virions. DNA sequencing of the H2 ts 125 fiber gene revealed two point mutations at nucleotides 3970 (C*TT leads to T*TT) and 4958 (GC*T leads to GT*T), corresponding to two amino acid changes at positions 105 and 434, respectively. The 105 mutation consisted of a conservative change Leu leads to Phe; the 434 interchange was Ala leads to Val, usually considered as nonconservative. The possibility of a donor site for splicing created by the mutation at codon GTT was eliminated on the basis of S1 nuclease analysis data. All these results suggested that either one or both mutations concerned highly organized domain(s) of the fiber polypeptide chain, resulting in aberrant mobility in SDS-polyacrylamide gels and temperature-sensitivity.

Acetylation↗
PubMed1983

Nucleotide sequences of feline sarcoma virus long terminal repeats and 5' leaders show extensive homology to those of other mammalian retroviruses.

The nucleotide sequences of the Gardner-Arnstein feline sarcoma virus (FeSV) long terminal repeat and the adjacent leader sequences 5' to the viral gag gene were determined. These were compared with homologous portions of Synder-Theilen FeSV and with previously published sequences for Moloney murine sarcoma virus and simian sarcoma virus proviral DNA. More than 75% of the residues in the FeSV R and U5 regions were homologous to sequences within the same regions of the other viral long terminal repeats. Unexpectedly, alignment of the FeSV sequences with those of the Moloney murine sarcoma and simian sarcoma viruses showed similar extents of homology within U3. The homologous U3 regions included the inverted repeats, a single set of putative enhancer sequences, corresponding to a "72-base-pair" repeat, and sequences, including the CAT and TATA boxes, characteristic of eucaryotic promotors. The 5' leader sequences of both FeSV strains included a binding site for prolyl tRNA and a putative splice donor sequence. In addition, the FeSV leader contained a long open reading frame which was adjacent to and in phase with the ATG codon at the 5' end of the FeSV gag gene. The open reading frame could code for a signal peptide of about 7.4 kilodaltons. Our results support the concept that the virogenic portions of both FeSV and simian sarcoma virus were ancestrally derived from viruses of rodent origin, with conservation of regulatory sequences as well as the viral structural genes.

Base Sequence↗