Molecular analysis of glycophorin A and B gene structure and expression in homozygous Miltenberger class V (Mi.V) human erythrocytes (original) (raw)
Related papers
Proceedings of The National Academy of Sciences, 1993
Human glycophorin A, B, and E (GPA, GPB, and GPE) genes belong to a gene family located at the long arm of chromosome 4. These three genes are homologous from the 5'-flanking sequence to the Alu sequence, which is 1 kb downstream from the exon encoding the transmembrane domain. Analysis of the Alu sequence and flanking direct repeat sequences suggested that the GPA gene most closely resembles the ancestral gene, whereas the GPB and GPE genes arose by homologous recombination within the Alu sequence, acquiring 3' sequences from an unrelated precursor genomic segment. Here we describe the identification of this putative precursor genomic segment. A human genomic library was screened by using the sequence of the 3' region of the GPB gene as a probe. The genomic clones isolated were found to contain an Alu sequence that appeared to be involved in the recombination. Downstream from the Alu sequence, the nucleotide sequence of the precursor genomic segment is almost identical to that of the GPB or GPE gene. In contrast, the upstream sequence of the genomic segment differs entirely from that of the GPA, GPB, and GPE genes. Conservation of the direct repeats flanking the Alu sequence of the genomic segment strongly suggests that the sequence of this genomic segment has been maintained during evolution. This identified genomic segment was found to reside downstream from the GPA gene by both gene mapping and in situ chromosomal localization. The precursor genomic segment was also identified in the orangutan genome, which is known to lack GPB and GPE genes. These results indicate that one of the duplicated ancestral glycophorin genes acquired a unique 3' sequence by unequal crossing-over through its Alu sequence and the further downstream Alu sequence present in the duplicated gene. Further duplication and divergence of this gene yielded the GPB and GPE genes.
Promoter sequence and chromosomal organization of the genes encoding glycophorins A, B and E
Gene, 1990
The promoter and exon I sequences of the genes encoding erythrocyte glycophorins GPA, GPB and GPE were investigated in detail, both from a genomic clone sorted out of a human leukocyte library and from genomic clones obtained by polymerase chain reaction amplification of total genomic DNA from control individuals and from GPA and/or GPB deletion variarJts. The three exons 1 and upstream sequences were shown to be highly homologous with only a few point mutations that did not affect the potential cis-acting elements (CACCC, NF-EI and NF-E2) that are present in the same position ~thin the three genes. Moreover, these genes share the same transcription start point. Analysis of the exon l and promoter sequences together with the gene defects occurring in the GP variants indicate that unequal cross-overs between the three genes are responsible for deletiow, and the generation of hybrid gene structures in which the promoter of one gene is brought close to another gene of the family. On the basis of these studies, a model of the gene organization is proposed to explain the rearrangements occurring in the variants.
A novel gene member of the human glycophorin A and B gene family. Molecular cloning and expression
European Journal of Biochemistry, 1990
A new gene closely related to the glycophorin A (GPA) and glycophorin B (GPB) genes has been identified in the normal human genome as well as in that of persons with known alterations of GPA and/or GPB expression. This gene, called glycophorin E (GPE), is transcribed into a 0.6-kb message which encodes a 78-amino-acid protein with a putative leader peptide of 19 residues. The first 26 amino acids of the mature protein are identical to those of M-type glycophorin A (GPA), but the C-terminal domain (residues 27 -59) differs significantly from those of glycophorins A and B (GPA and GPB). The GPE gene consists of four exons distributed over 30 kb of DNA, and its nucleotide sequence is homologous to those of the GPA and GPB genes in the 5' region, up to exon 3. Because of branch and splice site mutations, the GPE gene contains a large intron sequence partially used as exons in GPA and GPB genes. Compared to its counterpart in the GPB gene, exon 3 of the GPE gene contains several point mutations, an insertion of 24 bp, and a stop codon which shortens the reading frame. Downstream from exon 3, the GPE and the GPB sequences are virtually identical and include the same Alu repeats. Thus, it is likely that the GPE and GPB genes have evolved by a similar mechanism. From the analysis of the GPA, GPB and GPE
Recombinant glycophorins C and D as tools for studying Gerbich blood group antigens
Transfusion, 2004
BACKGROUND: The Gerbich blood group system antigens are carried on glycophorin C (GPC) and glycophorin D (GPD) and variants thereof. These glycoproteins have been expressed in a heterologous system to study the individual antigens and to determine whether An a is antithetical to Ge2. STUDY DESIGN AND METHODS: cDNAs encoding GPC, GPD, GPC.Yus, GPC.Ge, GPC.Ls a , and GPD.Ls a were transfected and stably expressed in a human embryonic kidney cell line (293T). Individual Gerbich antigens were analyzed with MoAbs and human polyclonal antibodies by flow cytometry and immunoblotting. Recombinant GPD and GPD.An(a) were expressed transiently and analyzed for expression of Ge2 and An a antigens. RESULTS: All recombinant variants were detected with sialidase-resistant and-sensitive anti-Ge2, anti-Ge3, and anti-Ge4. Ge4 antigen expression was depressed in GPC.Ls(a) transfectants as well as on Ls(a+) RBCs. GPD.An(a) recombinant protein expressed An a and Ge2 antigens. CONCLUSION: Cell lines stably expressing glycosylated Gerbich proteins were developed in a heterologous system by transfecting individual variant forms of GPC and GPD. Unexpectedly, it was found that Ge4 antigen is reduced in both the GPC.Ls(a) recombinant and the Ls(a+) RBCs. It was also shown that An a and Ge2 antigens were expressed on a single GPD.An(a) protein and, therefore, they cannot be antithetical.
Duplication of exon 3 in the glycophorin C gene gives rise to the Lsa blood group antigen
Transfusion, 1994
Background: The Gerbich-related Lsa blood group antigen (Ge6) resides on the higher-molecular-weight forms of gl cophorin C (GPC) and glycophorin D (GPD). Southern blot analysis has previousb revealed an additional GPC exon 3 insert in the enomic DNA from an Ls a+) individual. total RNA prepared from the E stein-Barr virus-transformed lymphocytes of an Ls(a+) individual was used in the syntEesis of first-strand cDNA.The first-strand cDNA served as a template for the amplification of GPC-related DNA b polymerase chain reaction. After subcloning, the polymerase chain reaction c D~A was sequenced with a kit. Hemag lutination inhibition of anti-Lsa sera with synthetic peptides was performed to identify R e locatlon of Lsa on the GPC.Lsa protein.
Identification of members of the P-glycoprotein multigene family
Molecular and Cellular Biology, 1989
Overproduction of P-glycoprotein is intimately associated with multidrug resistance. This protein appears to be encoded by a multigene family. Thus, differential expression of different members of this family may contribute to the complexity of the multidrug resistance phenotype. Three lambda genomic clones isolated from a hamster genomic library represent different members of the hamster P-glycoprotein gene family. Using a highly conserved exon probe, we found that the hamster P-glycoprotein gene family consists of three genes. We also found that the P-glycoprotein gene family consists of three genes in mice but has only two genes in humans and rhesus monkeys. The hamster P-glycoprotein genes have similar exon-intron organizations within the 3' region encoding the cytoplasmic domains. We propose that the hamster P-glycoprotein gene family arose from gene duplication. The hamster pgp1 and pgp2 genes appear to be more closely related to each other than either gene is to the pgp3 ...
Blood
Glycophorin C (GPC) and glycophorin D (GPD) are homologous sialoglycoproteins in the human red blood cell membrane. Both are thought to be encoded by the GPC gene (GYPC). We report that the rare blood group antigen, Ana, is expressed on GPD but not on GPC. cDNA was synthesized from total RNA obtained from two unrelated, heterozygous Ana+ blood donors and analyzed by the polymerase chain reaction using primers that spanned sequences encoded by the GYPC gene. The expected 412-bp fragment was generated, and sequencing of the amplified product showed a G-->T substitution at nucleotide 67 of the coding sequence, resulting in the substitution of alanine by serine at amino acid residue 23 of GPC and, presumably, residue 2 of GPD. To explain the expression of Ana on GPD but not on GPC, we postulate that the conformation of the amino acid residues at the N-terminal region of GPD determines the antigenic expression as this conformation would be different from that of the same sequence of a...
European Journal of Biochemistry, 1987
Human erythrocytes carry several transmembrane glycoproteins, among which the two minor species associated with the blood group Gerbich (Ge) antigens, GP C and GP D, play pivotal role since they interact with the membrane cytoskeleton and contribute to maintain the normal red cell shape. On the red cells from two categories of homozygous donors lacking the Ge determinants (Ge:-1,-2,-3 and Ge:-1,-2,3), GP C and GP D are missing but instead there is a new glycoprotein, easily detected by SDS/polyacrylamide gel electrophoresis, which exhibits some properties shared by GP C and GP D. This was shown by immunochemical analyses with a murine monoclonal antibody, extraction of the glycoproteins by organic solvents and binding studies with the 12'1labelled Lens culinaris lectin. The red cells from obligate heterozygotes for the Ge:-1,-2,-3 condition also carry this new glycoprotein component but in a much lesser amount than expected on the basis of one gene dose response.