Identification of the Dombrock blood group glycoprotein as a polymorphic member of the ADP-ribosyltransferase gene family

Abstract

Identification of the 25 known human blood group molecules is of fundamental importance for the fields of erythroid cell biology and transfusion medicine. Here we provide the first molecular description of the “Dombrock” blood group system. A candidate gene was identified by in silico analyses of approximately 5000 expressed sequence tags (ESTs) from terminally differentiating human erythroid cells. Transfection experiments demonstrated specific binding of anti-Dombrock and confirmed glycosylphosphatidylinositol membrane attachment. Dombrock expression is developmentally regulated during erythroid differentiation and occurs at highest levels in the fetal liver. Homology studies suggest that the Dombrock molecule is a member of the adenosine 5′-diphosphate (ADP)–ribosyltransferase ectoenzyme gene family. Genotypic comparisons suggest Doa versus Dob antigenicity results from a single amino acid substitution within an encoded arginine-glycine-aspartic acid (RGD) motif of the molecule.

Polymerase chain reaction with sequence‐specific primers‐based genotyping of the human Dombrock blood group DO1 and DO2 alleles and the DO gene frequencies in Chinese blood donors

“…The third substitution, A to G at nucleotide position 892 (Fig. 1b), corresponded to DO1 and DO2 alleles, as reported previously [8]. Sequence alignment analysis indicated that the DNA sequences of these two Chinese samples are identical to the DOK1 and BAC clone sequences (data not shown), further supporting the validity of this typing method.…”

“…Recently in a linkage study the DO locus was assigned to chromosome 12p12.3‐p13.2 (chromosome 12, short arm, region 1, band 2, sub‐band 3, through band 3, sub‐band 2) [7]. More recently, the DO gene has been successfully cloned, ending a long period of searching for the molecular basis of the DO1 / DO2 polymorphism [8]. Homology studies suggested that the DO molecule is a member of the adenosine 5′‐diphosphate (ADP)‐ribosyltransferase ectoenzyme gene family [8].…”

“…More recently, the DO gene has been successfully cloned, ending a long period of searching for the molecular basis of the DO1 / DO2 polymorphism [8]. Homology studies suggested that the DO molecule is a member of the adenosine 5′‐diphosphate (ADP)‐ribosyltransferase ectoenzyme gene family [8]. DO1 and DO2 alleles are the result of a single nucleotide substitution causing an amino acid change within an encoded arginine–glycine–aspartic acid (RGD) motif of the molecule [8].…”

“…Homology studies suggested that the DO molecule is a member of the adenosine 5′‐diphosphate (ADP)‐ribosyltransferase ectoenzyme gene family [8]. DO1 and DO2 alleles are the result of a single nucleotide substitution causing an amino acid change within an encoded arginine–glycine–aspartic acid (RGD) motif of the molecule [8]. On the basis of these findings, we have developed, for the first time, a polymerase chain reaction with sequence‐specific primers (PCR–SSP)‐based DO1 and DO2 genotyping method using newly designed allele‐specific primers.…”

“…: AF29004) within exon 2 results in the substitution of asparagine (N) for aspartic acid (D) at position 265 of the protein sequence. Serological testing indicated that N265 and D265 corresponded to the phenotypes DO:1,−2 [DO(a+b−)] and DO:−1,2 [DO(a−b+)], respectively [8]. In order to detect A892G substitution, two allele‐specific reverse primers and a single forward‐consensus primer were designed according to the DOK1 clone sequence and the human chromosome 12 working draft sequence (BAC clone, GenBank acc.…”