In:
The Journal of Immunology, The American Association of Immunologists, Vol. 171, No. 3 ( 2003-08-01), p. 1312-1318
Abstract:
The pig δ gene is located ∼3.4 kb downstream of the second transmembrane exon of the μ gene and shows a similar genomic structure to its counterpart in cow with three exons encoding the CH1, CH2, and CH3 domains. The porcine genomic δCH1 exon has been replaced by a recent duplication of the μCH1 and its flanking sequences, a genetic event that also led to the formation of a short switch δ region, immediately upstream of the δ gene. The δCH1 exhibits a 98.7% similarity (314 of 318 bp) to the μCH1 at the DNA level, whereas the homologies between the δCH2 and μCH3, and the δCH3 and μCH4 are only 33.3 and 35.8%, respectively. Either of the two CH1 exons (μ and δ) could be observed in the expressed porcine IgD H chain cDNA sequences VDJ-μCH1-H-δCH2-δCH3 or VDJ-δCH1-H-δCH2-δCH3, showing a pattern that has not been observed previously in vertebrates. In addition, transfection of a human B cell line, using artificial constructs resembling the porcine Cμ-Cδ locus, also generated both VDJ-μCH1-δCH1-H1-δCH2 and VDJ -δCH1-H1-δCH2 transcripts. An examination of the pig δ genomic sequence shows a putative, second hinge region-encoding exon. Due to the lack of a normal branchpoint sequence for RNA splicing, this exon is not present in the normal pig δ cDNA. However, the exon could be spliced into most of the expressed transcripts in vitro in cell transfection experiments after introduction of a single T nucleotide to restore the branchpoint sequence upstream of the putative H2 exon.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.171.3.1312
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2003
detail.hit.zdb_id:
1475085-5
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