A unique second donor splice site in the intron 5 sequence of the HLA-A*11 alleles results in a class I transcript encoding a molecule with an elongated cytoplasmic domain.
Full-length cDNA sequencing of the A*1103 allele revealed an insertion of 18 bp between exon 5 and 6. We hypothesized that this could be the result of alternative splicing. Sequencing of intron-5 of A*1101, *1102 and *1103 alleles demonstrated that this 18-bp insertion consisted of the 5'-end of intron 5, concluded by a second in-frame donor splice site. Alignment of the 5'-end intron 5 sequence of A*1101-3 with that of A*0101, *0201 and 0301 revealed a unique polymorphism at position 17 of the intron (A to G) that created this second donor splice site. To exclude the possibility of an Epstein-Barr virus (EBV)-induced event, reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed on both peripheral blood mononuclear cells (PBMC) and EBV-transformed b-LcL's of several A*11-positive individuals, using primers spanning exons 5 and 6. Without exception, both cell types revealed two products for A*11. Densitometric analysis using EBV-transformed b-LcL's and PBMC indicated a ratio of approximately 4:1 in favor of the alternative splice product. Notably, except for the A*11's none of the other A-locus alleles yields this alternative splice product. Translation of this product will result in a protein that has an additional 6 amino acids in its cytoplasmic domain. This introduces a negative charge just behind the basic anchor residues of the cytoplasmic segment and results in the loss of the single potential protein kinase C phosphorylation site.
Tijssen
H J
HJ
Blood Transfusion Service, University Medical Center St. Radboud, Nijmegen, The Netherlands.
Sistermans
E A
EA
Joosten
I
I
D000483:Alleles; D017398:Alternative Splicing / Q000276:immunology; D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology; D002461:Cell Line, Transformed; D003593:Cytoplasm / Q000737:chemistry; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D015234:HLA-A Antigens / Q000737:chemistry* / Q000235:genetics*; D059870:HLA-A11 Antigen; D006801:Humans; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis / Q000276:immunology; D017434:Protein Structure, Tertiary; D022821:RNA Splice Sites / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic / Q000276:immunology*
D015234:HLA-A Antigens; D059870:HLA-A11 Antigen; D022821:RNA Splice Sites; D012333:RNA, Messenger