DIFFERENT GENOTYPES CAUSING INDISCERNIBLE PATTERNS OF A EXPRESSION ANA(EL) RED-BLOOD-CELLS AS VISUALIZED BY SCANNING IMMUNOGOLD ELECTRON-MICROSCOPY

Background and Objectives: The published sequence of the weak A subgro up A(el) gene from Swedish individuals showed a G insertion in exon VI I, causing a frameshift at codon 268 (the A(1) gene has 353 codons). W e wished to sequence exons VI and VII of two Norwegian A,, individuals and compare the expression of A substance on RBC from different A(el) individuals. Materials and Methods: Exon VI and VII were amplified by PCR, cloned in M13 and sequenced. A structure expression on A,I RBC w as studied by the immunogold technique. Results: In contrast to the Sw edish A(el) individuals, the two Norwegians had consensus A(1) sequenc es in exon VI and VII. However, the patterns of A expression were indi scernible from the Swedish cases as visualized by immunogold labeling in SEM. In both cases, a few (1-2%) RBC were very strongly labeled, so me were weakly labeled and the majority (95%) were unlabeled. Conclusi on: Although some A(el) individuals have an inserted nucleotide in exo n VII of the ABO gene, others have consensus A(1) sequence in exon VI and VII. However, we could not find any differences in phenotype by im munogold labeling in SEM.