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Duplication of exon 3 in the glycophorin C gene gives rise to the Ls a blood group antigen
Author(s) -
Reid M. E.,
Mawby W.,
King M.J.,
Sistonen P.
Publication year - 1994
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1994.341195065034.x
Subject(s) - microbiology and biotechnology , exon , biology , complementary dna , rapid amplification of cdna ends , peptide sequence , nucleic acid sequence , southern blot , gene , genetics , molecular cloning
BACKGROUND: The Gerbich‐related Ls a blood group antigen (Ge6) resides on the higher‐molecular‐weight forms of glycophorin C (GPC) and glycophorin D (GPD). Southern blot analysis has previously revealed an additional GPC exon 3 insert in the genomic DNA from an Ls(a+) individual. STUDY DESIGN AND METHODS: To confirm the duplication of exon 3 in the GPC mRNA, total RNA prepared from the Epstein‐Barr virus‐ transformed lymphocytes of an Ls(a+) individual was used in the synthesis of first‐strand cDNA. The first‐strand cDNA served as a template for the amplification of GPC‐related DNA by polymerase chain reaction. After subcloning, the polymerase chain reaction cDNA was sequenced with a kit. Hemagglutination inhibition of anti‐Ls a sera with synthetic peptides was performed to identify the location of Lsa on the GPC.Ls a protein. RESULTS: Sequencing the GPC.Ls a cDNA showed an insert of 84 nucleotides, which corresponds to the entire sequence of exon 3 in the GPC gene (GYPC). Since the exon 3‐duplicated exon 3 boundary of GYPC.Ls a encodes a novel amino acid sequence on GPC.Lsa and GPD.Ls a , synthetic peptides consisting of the amino acids flanking this junction were used to determine the amino acid sequence that is essential for expression of Ls a . The peptide DIVVIA/EPDPG was noninhibitory, while peptides with the sequence TPTIMDIVVIA/EPDPG or SPSVLDIVVIA/EPDPG inhibited anti‐Ls a reactivity. CONCLUSION: Ls a is located within the sequence of amino acids encoded by the nucleotides at the exon 3‐ duplicated exon 3 boundary, and the conformation of this peptide sequence is important for recognition of Ls a by human anti‐Ls a .