Involvement of Ser103 of the Rh polypeptides in G epitope formation.
BACKGROUND
Almost all red cells that carry D and/or C antigens also express the G antigen (Rh12). A study was conducted on the molecular background of the G epitope.


METHODS
Two unrelated donors with the rare ccDEe, G- phenotype and one donor with the ccEe, G+ phenotype were studied. Genomic DNA and cDNA of these donors were studied with polymerase chain reaction, Southern blot, and sequence analysis, with special focus on exon 2, because it is only in this exon that there are supposed to be similarities between RHD and the RHC allele, but not between RHD and the RHc allele.


RESULTS
In both ccDEe, G- donors, a nucleotide substitution was found in exon 2 of RHD; T307 was replaced by C307, which predicted a Ser->Pro substitution at amino acid position 103 of the D polypeptide. The ccEe, G+ donor carried the complete exon 2 of RHD. Moreover, despite the absence of all known D epitopes, this donor also carried RHD characteristics in exons 1 to 3 and exon 9 and further downstream.


CONCLUSIONS
Ser103, encoded by exon 2 of the RH genes, is involved in G epitope formation.
Faas
B H
BH
Central Laboratory, The Netherlands Red Cross Blood Transfusion Service, Amsterdam, The Netherlands.
Beckers
E A
EA
Simsek
S
S
Overbeeke
M A
MA
Pepper
R
R
van Rhenen
D J
DJ
von dem Borne
A E
AE
van der Schoot
C E
CE
D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis / Q000737:chemistry; D015245:Deoxyribonuclease BamHI; D015247:Deoxyribonuclease HindIII; D000939:Epitopes / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D005091:Exons; D005260:Female; D006801:Humans; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012204:Rh-Hr Blood-Group System / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology; D017422:Sequence Analysis, DNA; D012694:Serine
D000939:Epitopes; D012204:Rh-Hr Blood-Group System; D012694:Serine; D004247:DNA; D015245:Deoxyribonuclease BamHI; D015247:Deoxyribonuclease HindIII