Lung-Chih Yu

International Society of Blood Transfusion Committee on Terminology for Red Cell Surface Antigens: Cape Town report.

The Committee met in Cape Town during the 2006 Inter-national Society of Blood Transfusion (ISBT) Congress (seeAppendix 1 for Committee members). Some changes to theclassification documented in Blood Group Terminology 2004[1] were agreed and are described below. The full updatedclassification can be found on the Blood Group Terminologywebsite at http://www.blood.co.uk/ibgrl. New antigens wereadded to the MNS, Kell, Scianna, Cromer, Indian, Knops,and JMH systems (Table 1). In line with convention, aminoacid positions are numbered with the translation-initiatingmethionine as 1, although the more traditional numberingfor glycophorin A, with number 1 representing the first aminoacid of the mature protein, is also provided.

Heterogeneity of the Human H Blood Group α (1,2) Fucosyltransferase Gene among Para-Bombay Individuals

Background and objectives: The para‐Bombay phenotype has a relatively high frequency of about 1 in 8,000 Taiwanese. Studies were carried out on eight healthy and unrelated Taiwanese with the para‐Bombay phenotype to cast light on its immunogenetic basis. Materials and methods: Blood and saliva samples were tested with standard hemagglutination techniques. Salivary ABH substances were determined by hemagglutination inhibition. PCR techniques were used to amplify the coding region of the H genes. Results: Five different h alleles, designated as h1, h2, h3, h4 and h5, were identified in the Taiwanese with the para‐Bombay phenotype. The h1 allele loses one of the three AG repeats located at the nucleotides 547–552 of the H gene, whereas two of the three T repeats located at the nucleotides 880–882 are deleted in the h2 allele. The h3 allele contains a C658 to T missense mutation, whereas two missense mutations, C35 to T and A980 to C were identified in the h4 allele. A T460 to C missense is present in the h5allele. The h5 allele was identified in an individual whose red blood cells contain blood group A antigen but not H antigen, and thus may be considered a weak variant of the H gene. Conclusions: So far no biologic relevance of the H antigen has been discovered, and its deficiency does not seem to produce any deleterious effects. There may be better understanding of the evolutionary basis for the polymorphisms at these loci after systematic study of different ethnic populations.

Molecular genetic analysis for the Ae1 and A3 alleles.

BACKGROUND: In addition to the common ABO phenotypes, numerous phenotypes with a weak expression of the A or B antigens on RBCs have been found. This study describes the molecular genetic analysis of the Ael and the A3 phenotypes.

A novel cis‐AB allele derived from a unique 796C>A mutation in exon 7 of ABO gene

BACKGROUND:  The cis‐AB phenotype is very rare, and only three genotypes that correspond to specific ABO allele changes have been reported. Cis‐AB01 involves the A102 allele with a nonsynonymous substitution G803C in exon 7, whereas cis‐AB02 and cis‐AB03 involve different nonsynonymous substitutions A796C and C700T, respectively, on the B101 allele background. The nucleotide substitutions give rise to a change of the respective glycosyltransferase, resulting in varying bifunctional AB transferase activities.

A newly identified nonsecretor allele of the human histo-blood group α(1,2)fucosyltransferase gene (FUT2)

Background and Objectives: The human Secretor α(1,2)fucosyltransferase gene determines the ABH secretor status and influences the Lewis phenotype of an individual. Studies were carried out on the Lewis (a+b–) nonsecretors of different groups indigenous to Taiwan to demonstrate their se genotypes. Methods: The Lewis phenotype of the blood samples was determined by a microplate method. The se genotypes of the individuals with the Lewis (a+b–) phenotype were analyzed by a polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP) method designed for the se alleles reported previously. PCR and cloning techniques were used to determine the coding sequence of the novel se gene. Results: A new se allele, se685, with a three–nucleotide deletion of GTGGT to GT in the coding region of nucleotides 685 through 689 was identified in a Le (a+b–) nonsecretor from the Ami tribe indigenous to Taiwan. The deletion predicts the loss of the amino acid Val230 in the corresponding secretor enzymes C–terminal segment. The distribution of the se685 allele in the Ami tribe was further verified by PCR–RFLP analysis. Conclusion: The Se gene exhibits heterogeneity with some Se alleles being common but others displaying a unique distribution in different ethnic populations. The newly identified se685 allele seems to exist only in the Ami tribe indigenous to Taiwan.

Phosphorylation status of transcription factor C/EBPα determines cell-surface poly-LacNAc branching (I antigen) formation in erythropoiesis and granulopoiesis

The cell-surface straight and branched repeats of N-acetyllactosamine (LacNAc) units, called poly-LacNAc chains, characterize the histo-blood group i and I antigens, respectively. The transition of straight to branched poly-LacNAc chain (i to I) is determined by the I locus, which expresses 3 IGnT transcripts, IGnTA, IGnTB, and IGnTC. Our previous investigation demonstrated that the i-to-I transition in erythroid differentiation is regulated by the transcription factor CCAAT/enhancer binding protein alpha (C/EBPalpha). In the present investigation, the K-562 cell line was used as a model to show that the i-to-I transition is determined by the phosphorylation status of the C/EBPalpha Ser-21 residue, with dephosphorylated C/EBPalpha Ser-21 stimulating the transcription of the IGnTC gene, consequently resulting in I branching. Results from studies using adult erythropoietic and granulopoietic progenitor cells agreed with those derived using the K-562 cell model, with lentiviral expression of C/EBPalpha in CD34(+) hematopoietic cells demonstrating that the dephosphorylated form of C/EBPalpha Ser-21 induced the expression of I antigen, granulocytic CD15, and also erythroid CD71 antigens. Taken together, these results demonstrate that the regulation of poly-LacNAc branching (I antigen) formation in erythropoiesis and granulopoiesis share a common mechanism, with dephosphorylation of the Ser-21 residue on C/EBPalpha playing the critical role.

Identification of Further Elongation and Branching of Dimeric Type 1 Chain on Lactosylceramides from Colonic Adenocarcinoma by Tandem Mass Spectrometry Sequencing Analyses

Mammalian glycan chain elongation is mostly based on extending the type 2 chain, Galβ1–4GlcNAc, whereas the corresponding type 1 chain, Galβ1–3GlcNAc, is not normally extended. In a broader context of developing high sensitivity mass spectrometry methodologies for glycomic identification of Lea versus Lex and linear versus branched poly-N-acetyllactosamine (polyLacNAc), we have now shown that the dimeric type 1 glycan chain, as carried on the lactosylceramides of a human colonic adenocarcinoma cell line, Colo205, not only can be further extended linearly but can likewise be branched at C6 of 3-linked Gal in a manner similar to polyLacNAc. A combination of chemical and enzymatic derivatization coupled with advanced mass spectrometry analyses afforded unambiguous identification of a complex mixture of type 1 and 2 hybrids as well as those fucosylated variants founded exclusively on linear and branched trimeric type 1 chain. We further showed by in vitro enzymatic synthesis that extended type 1 and the hybrid chains can be branched by all three forms of the human I branching enzymes (IGnT) currently identified but with lower efficiency and stringency with respect to branching site preference. Importantly, it was found that a better substrate is one that carries a Gal site for branching that is extended at the non-reducing end by a type 2 and not a type 1 unit, whereas the IGnTs are less discriminative with respect to whether the targeted Gal site is itself β3- or β4-linked to GlcNAc at the reducing end.

Expression of the histo-blood group B gene predominates in AB-genotype cells

BACKGROUND: It has been demonstrated that the 43‐bp minisatellite sequence in the 5′ region of the ABO gene plays an important role in its transcriptional regulation. It was determined in previous investigations that the structure of the minisatellite enhancer was specific to A, B, and O alleles.

Silencing of p29 Affects DNA Damage Responses with UV Irradiation

Human p29 is a newly identified nuclear protein whose function is largely undetermined. We found that p29 associated with chromatin, interacted with MCM3, and localized with proliferating cell nuclear antigen foci in the S phase. Silencing of p29 using small interfering RNA duplexes reduced DNA synthesis and increased the expression of p107, a member of the RB family, and of cyclin-dependent kinase inhibitor p21, accompanied with a decreased expression of DNA polymerase alpha. Lethal events consisting of premature chromatin condensation with a reduced Chk1 phosphorylation were observed in p29-depleted cells in response to UV irradiation. Intriguingly, the phosphorylation of ataxia telangectasia-mutated kinases at S1981 was suppressed in p29-depleted HeLa cells with UV irradiation, but not in hydroxyurea- and ionizing radiation-treated cells. Taken together, these results reveal a novel function of p29 in the regulation of DNA replication checkpoint responses.

Polymorphism and distribution of the Secretor α(1,2)‐fucosyltransferase gene in various Taiwanese populations

BACKGROUND: The Secretor gene (Se or FUT2), which produces α(1,2)‐fucosyltransferase, exhibits extensive polymorphism. Six Se genes, including the weak Se (Sew or Se385) and three nonsecretor alleles (se571, se685, and se849) have been detected in various populations of Taiwan. The distribution of various Lewis phenotypes among the Taiwanese population groups has been shown to vary considerably.