Expression of RHD and RHCE gene products using retroviral transduction of K562 cells establishes the molecular basis of Rh blood group antigens

Abstract

Retroviral-mediated gene transfer using cDNA transcripts of the RHD and RHCE genes resulted in the isolation of K562 clones expressing D and G or c and E antigens, respectively. These results represent the first direct demonstration that the RHD gene encodes the D and G antigens and the RHCE gene encodes the c and E antigens. Both c and E antigens were expressed after transduction of K562 cells with a single cDNA, indicating that the c antigen does not arise by alternative splicing (exon skipping) of the product of the RHCE gene, as has been suggested.

Molecular basis of the LOCR (Rh55) antigen

“…Based on the DNA sequencing results presented in this report, we have established that a heterozygous (286G>A) point mutation underlying a predicted Gly96Ser substitution in the Rhce protein defines the low-incidence antigen known as LOCR (Rh55). Given that c expression is weakened in the presence of LOCR, 18 we suggest that the proximity of the LOCR polymorphism to Pro102 and Pro103, residues important in c antigen expression, [25][26][27][28] could be responsible. As for the observed altered expression of e in one LOCR+ family member, 18 we offer the explanation that the second and fourth extracellular loops of the three-dimensional Rhce protein are within close proximity, and the presence of the LOCR epitope could affect e antigen expression.…”

Rh‐null phenotype caused by a complete RHAG deletion

“…1,2 Mutations in RHAG can lead to reduced expression (Rhmod phenotype) or no expression (Rhnull phenotype) of Rh antigens on the RBC membrane. [3][4][5][6] Reported RHAG mutations that cause a Rhnull phenotype include missense substitutions, altered splicing substitutions, and small (one-to two-nucleotide) deletions. 7 Here we report a Rhnull case caused by a complete deletion of the RHAG gene.…”

Molecular background of D(C)(e) haplotypes within the white population

“…4 However, only the S103P substitution predicted to be located on the external loop 2 of the polypeptide is strictly correlated with C/c expression. 5,6 The molecular genetic basis of the E/e polymorphism appears much simpler than that of the C/c polymorphism, as it is caused by a single nucleotide substitution in exon 5 of RHCE, resulting in a P226A amino acid substitution predicted on the external loop 4 of the polypeptide. 4 E and e expression is probably complex, however, as amino acid substitutions at other positions or gene rearrangements may alter their expression.…”