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Antoine Blancher – One of the best experts on this subject based on the ideXlab platform.

  • Evolutionary dynamics of the human ABO Gene
    Human Genetics, 2008
    Co-Authors: Francesc Calafell, Francis Roubinet, Anna Ramírez-Soriano, Naruya Saitou, Jaume Bertranpetit, Antoine Blancher

    Abstract:

    The ABO polymorphism has long been suspected to be under balancing selection. To explore this possibility, we analyzed two datasets: (1) a set of 94 23-Kb sequences in European- and African-Americans produced by the Seattle SNPs project, and (2) a set of 814 2-Kb sequences in O alleles from seven worldwide populations. A phyloGenetic analysis of the Seattle sequences showed a complex pattern in which the action of recombination and Gene conversion are evident, and in which four main lineages could be individuated. The sequence patterns could be linked to the expected blood group phenotype; in particular, the main mutation giving rise to the null O allele is likely to have appeared at least three times in human evolution, giving rise to allele lineages O02, O01, and O09. However, the Genealogy changes along the Gene and variations of both numbers of branches and of their time depth were observed, which could result from a combined action of recombination and selection. Several neutrality tests clearly demonstrated deviations compatible with balancing selection, peaking at several locations along the Gene. The time depth of the Genealogy was also incompatible with neutral evolution, particularly in the region from exons 6 to 7, which codes for most of the catalytic domain.

  • long term evolution of the cazy glycosyltransferase 6 ABO Gene family from fishes to mammals a birth and death evolution model
    Glycobiology, 2007
    Co-Authors: Annelaure Turcotdubois, Francis Roubinet, Stéphanie Despiau, Nicolai V. Bovin, Beatrice Le Moullacvaidye, Jacques Le Pendu, Antoine Blancher

    Abstract:

    Functional glycosyltransferase 6 (GT6) family members catalyze the transfer of galactose or N-acetylgalactosamine in α1,3 linkage to various substrates and synthesize structures related to the A and B histo-blood group antigens, the Forssman antigen, αGal epitope, and iGb3 glycolipid. In rat, mouse, dog, and cow genomes, we have identified three new mammalian Genes (GT6m5, GT6m6, and GT6m7) encoding putative proteins belonging to the GT6 family. Among these, GT6m6 protein does not display major alterations of the GT6 motifs involved in binding of the divalent cation and the substrate. Based on protein sequence comparison, Gene structure, and synteny, GT6 homologous sequences were also identified in bird, fish, and amphibian genomes. Strikingly, the number and type of GT6 Genes varied widely from species to species, even within phyloGenetically related groups. In human, except ABO functional alleles, all other GT6 Genes are either absent or nonfunctional. Human, mouse, and cow have only one ABO Gene, whereas rat and dog have several. In the chicken, the Forssman synthase-like is the single GT6 family member. Five Forssman synthase-like Genes were found in zebrafish, but are absent from three other fishes (fugu, puffer fish, and medaka). Two iGb3 synthase-like Genes were found in medaka, which are absent from zebrafish. Fugu, puffer fish, and medaka have an additional GT6 Gene that we termed GT6m8, which is absent from all other species analyzed here. These observations indicate that individual GT6 Genes have expanded and contracted by recurrent duplications and deletions during vertebrate evolution, following a birth-and-death evolution type.

  • Long-term evolution of the CAZY glycosyltransferase 6 (ABO) Gene family from fishes to mammals—a birth-and-death evolution model
    Glycobiology, 2007
    Co-Authors: Anne-laure Turcot-dubois, Francis Roubinet, Jacques Le Pendu, Béatrice Le Moullac-vaidye, Stéphanie Despiau, Nicolai V. Bovin, Antoine Blancher

    Abstract:

    Functional glycosyltransferase 6 (GT6) family members catalyze the transfer of galactose or N-acetylgalactosamine in α1,3 linkage to various substrates and synthesize structures related to the A and B histo-blood group antigens, the Forssman antigen, αGal epitope, and iGb3 glycolipid. In rat, mouse, dog, and cow genomes, we have identified three new mammalian Genes (GT6m5, GT6m6, and GT6m7) encoding putative proteins belonging to the GT6 family. Among these, GT6m6 protein does not display major alterations of the GT6 motifs involved in binding of the divalent cation and the substrate. Based on protein sequence comparison, Gene structure, and synteny, GT6 homologous sequences were also identified in bird, fish, and amphibian genomes. Strikingly, the number and type of GT6 Genes varied widely from species to species, even within phyloGenetically related groups. In human, except ABO functional alleles, all other GT6 Genes are either absent or nonfunctional. Human, mouse, and cow have only one ABO Gene, whereas rat and dog have several. In the chicken, the Forssman synthase-like is the single GT6 family member. Five Forssman synthase-like Genes were found in zebrafish, but are absent from three other fishes (fugu, puffer fish, and medaka). Two iGb3 synthase-like Genes were found in medaka, which are absent from zebrafish. Fugu, puffer fish, and medaka have an additional GT6 Gene that we termed GT6m8, which is absent from all other species analyzed here. These observations indicate that individual GT6 Genes have expanded and contracted by recurrent duplications and deletions during vertebrate evolution, following a birth-and-death evolution type.

Hans Wolf – One of the best experts on this subject based on the ideXlab platform.

  • The blood group ABO Gene transcript is down-regulated in human bladder tumors and growth-stimulated urothelial cell lines.
    Cancer research, 1996
    Co-Authors: Torben F. Ørntoft, Peter Meldgaard, Bent Pedersen, Hans Wolf

    Abstract:

    The molecular mechanism that in human bladder tumors leads to the loss of blood group ABO glycosyltransferase activity and, thereby, the loss of ABO antigens was investigated. In 15 tumors and 3 normal biopsies from blood group AB individuals and 7 tumors and 3 normal biopsies from blood group O individuals, mRNA was detected by a reverse transcription PCR (RT-PCR) assay, and the ABO blood group structure was determined by immunohistology. The RT-PCR spanned several introns in the ABO Gene to exclude DNA contamination, and the RT-PCR product was shown to reflect the ABO Gene message by dideoxy sequencing. The ABO mRNA was present in normal urothelium and low-grade tumors but disappeared from high grade tumors. This correlation to tumor grade was significant (P

  • the blood group ABO Gene transcript is down regulated in human bladder tumors and growth stimulated urothelial cell lines
    Cancer Research, 1996
    Co-Authors: Torben F. Ørntoft, Peter Meldgaard, Bent Pedersen, Hans Wolf

    Abstract:

    The molecular mechanism that in human bladder tumors leads to the loss of blood group ABO glycosyltransferase activity and, thereby, the loss of ABO antigens was investigated. In 15 tumors and 3 normal biopsies from blood group AB individuals and 7 tumors and 3 normal biopsies from blood group O individuals, mRNA was detected by a reverse transcription PCR (RT-PCR) assay, and the ABO blood group structure was determined by immunohistology. The RT-PCR spanned several introns in the ABO Gene to exclude DNA contamination, and the RT-PCR product was shown to reflect the ABO Gene message by dideoxy sequencing. The ABO mRNA was present in normal urothelium and low-grade tumors but disappeared from high grade tumors. This correlation to tumor grade was significant (P<0.04). Immunohistochemistry with monoclonal anti-blood group antibodies showed a complete correlation between the presence of mRNA and the presence of AB carbohydrate structures on cell surfaces. In two urothelial cell lines, genotyped as A/- and A/A, growth stimulation with the cholera toxin B subunit led to a total loss of ABO mRNA, and epidermal growth factor stimulation had an identical effect on one of the cell lines. We conclude that the ABO glycosylation in normal and malignant urothelium is regulated at the mRNA level, and that a mechanism associated with cell proliferation may trigger down-regulation of ABO mRNA.

Rainer Blasczyk – One of the best experts on this subject based on the ideXlab platform.

  • weak blood group b phenotypes may be caused by variations in the ccaat binding factor nf y enhancer region of the ABO Gene
    Transfusion, 2007
    Co-Authors: Axel Seltsam, Franz F. Wagner, Daniela Grüger, Christa Das Gupta, Christina Badedoeding, Rainer Blasczyk

    Abstract:

    BACKGROUND: Binding of CCAAT-binding factor NF-Y (CBF/NF-Y) to a 43-bp repeat unit in the minisatellite region in the 5′ region of the ABO Gene (CBF/NF-Y enhancer region) plays an important role in regulating the transcription of ABO Genes. The common ABO alleles were found to have CBF/NF-Y enhancer regions with specific numbers of 43-bp minisatellite repeats.

    MATERIAL AND METHODS: Blood samples from four healthy blood donors with weak B phenotypes were subjected to extensive ABO genotyping, including nucleotide sequencing of the 5′ regulatory region containing the CBF/NF-Y enhancer.

    RESULTS: The coding region of the ABO Genes exhibited common ABO*B101-heterozygous genotypes in all samples, but unexpected variations were observed in the CBF/NF-Y enhancer region. In two cases, the CBF/NF-Y enhancer motifs did not exhibit the expected ABO allele dependency. One, an ABweak sample was heterozygous for ABO*A101 and ABO*B101 but homozygous for the ABO*B101-specific CBF/NF-Y motif. The second had a common ABO*B101/ABO*O01 genotype but was heterozygous for ABO*A101- and ABO*O01-specific enhancer motifs. In the other two samples, novel CBF/NF-Y motifs were found. One contained a shortened version of an otherwise ABO*B101-specific CBF/NF-Y motif, and the other had a single-base substitution located 12 bp upstream from the beginning of the first 43-bp repeat of an ABO*B101-specific CBF/NF-Y enhancer sequence.

    CONCLUSION: The frequency of variations in the CBF/NF-Y region of the ABO Gene in these samples with presumably common ABO*B101 alleles suggests that weak blood group B phenotypes may be caused by sequence variations in the CBF/NF-Y regulatory region.

  • Weak blood group B phenotypes may be caused by variations in the CCAAT‐binding factor/NF‐Y enhancer region of the ABO Gene
    Transfusion, 2007
    Co-Authors: Axel Seltsam, Franz F. Wagner, Daniela Grüger, Christa Das Gupta, Christina Bade-doeding, Rainer Blasczyk

    Abstract:

    BACKGROUND: Binding of CCAAT-binding factor NF-Y (CBF/NF-Y) to a 43-bp repeat unit in the minisatellite region in the 5′ region of the ABO Gene (CBF/NF-Y enhancer region) plays an important role in regulating the transcription of ABO Genes. The common ABO alleles were found to have CBF/NF-Y enhancer regions with specific numbers of 43-bp minisatellite repeats.

    MATERIAL AND METHODS: Blood samples from four healthy blood donors with weak B phenotypes were subjected to extensive ABO genotyping, including nucleotide sequencing of the 5′ regulatory region containing the CBF/NF-Y enhancer.

    RESULTS: The coding region of the ABO Genes exhibited common ABO*B101-heterozygous genotypes in all samples, but unexpected variations were observed in the CBF/NF-Y enhancer region. In two cases, the CBF/NF-Y enhancer motifs did not exhibit the expected ABO allele dependency. One, an ABweak sample was heterozygous for ABO*A101 and ABO*B101 but homozygous for the ABO*B101-specific CBF/NF-Y motif. The second had a common ABO*B101/ABO*O01 genotype but was heterozygous for ABO*A101- and ABO*O01-specific enhancer motifs. In the other two samples, novel CBF/NF-Y motifs were found. One contained a shortened version of an otherwise ABO*B101-specific CBF/NF-Y motif, and the other had a single-base substitution located 12 bp upstream from the beginning of the first 43-bp repeat of an ABO*B101-specific CBF/NF-Y enhancer sequence.

    CONCLUSION: The frequency of variations in the CBF/NF-Y region of the ABO Gene in these samples with presumably common ABO*B101 alleles suggests that weak blood group B phenotypes may be caused by sequence variations in the CBF/NF-Y regulatory region.

  • Systematic analysis of the ABO Gene diversity within exons 6 and 7 by PCR screening reveals new ABO alleles.
    Transfusion, 2003
    Co-Authors: Axel Seltsam, Michael Hallensleben, Anke Kollmann, Jürgen Burkhart, Rainer Blasczyk

    Abstract:

    BACKGROUND: Mutations critical for ABO blood group phenotypes have predominantly been found in exons 6 and 7 of the ABO Gene, both of which encode the catalytic domain of ABO glycosyltransferase. To design rapid and reliable ABO genotyping assays, a profound knowledge of the prevalent alleles is required and a reliable sequence database needs to be established.

    STUDY DESIGN AND METHODS: A PCR screening system was established consisting of 102 different PCRs, each specific for a single nucleotide (nt) variation. The primer mixes were developed to walk from the 5′ to the 3′ end of exons 6 and 7 of the ABO Gene to screen for nt mutations at 50 known polymorphic sites. A total of 109 unrelated individuals with common and rare ABO characteristics were screened. All blood samples in which the PCR results were inconclusive or inconsistent with the ABO phenotypes were subjected to sequence analysis of exons 6 and 7.

    RESULTS: The results of PCR screening were conclusive and consistent with the ABO phenotypes in 90 cases. In the remaining 19 cases, PCR screening revealed unusual allele combinations or amplification results that were incompatible with known ABO allele combinations or subgroups predicted by serologic analysis. In these 19 cases, sequencing revealed new ABO alleles (one ABO*Ael allele, one ABO*B(A) allele and two ABO*O alleles) in two individuals with common and seven individuals with variant ABO phenotypes.

    CONCLUSION: This PCR screening strategy is an effective tool for obtaining deeper insight into the ABO Gene diversity and diversification and may be useful to increase the quality of the ABO sequence database.