ALTERNATIVE SPLICING OF RH BLOOD GROUP POLYPEPTIDE mRNA PRODUCES A NOVEL TRANSCRIPT CONTAINING A SHORT NUCLEOTIDE INSERTION ON HUMAN ERYTHROLEUKEMIC K562 CELLS

A novel isoform of the human Rh blood group polypeptide cDNA was isolated from human erythroleukemic K562 cells. This isoform was produced by deletion of the sequences derived from exons 2 and 3 of the RHCE gene and insertion of 44-bp into the resulting junction between exon 1 and 4 derived sequence. The deduced amino acid sequence revealed that the 44-bp insertion sequence contains an in-frame stop codon that causes premature chain termination. A sequence homology search using GenBank showed that the inserted sequence was derived from the intron between exons 1 and 2 of the RHCE gene. Moreover, analysis of the region surrounding the inserted sequence indicated that the insert was a cryptic exon flanked by consensus donor and acceptor splice sequences. This novel transcript was most likely produced by alternative splicing.