The human mRNA encoding the Goodpasture antigen is alternatively spliced.
The noncollagenous (NC1) domain of the human collagen alpha 3(IV)-chain is the primary target of autoantibodies produced in Goodpasture syndrome and, therefore, has been designated as the Goodpasture antigen. In this report, we show that Goodpasture antigen mRNA undergoes processing to at least two alternatively spliced forms in a variety of human tissues, resulting in the exclusion of sequence encoded by either one or two exons. Interestingly, no alternatively spliced forms were observed in bovine or rat tissues. The derived amino acid sequences of the two variant mRNA forms are identical and significantly shorter than that arising from the complete Goodpasture antigen mRNA. They lack the carboxyl-terminal region contributing to the formation of the Goodpasture epitope and all but one of the cysteines found in the complete form. These sequence characteristics suggest that, if translated, the variant Goodpasture antigen is likely to be defective in triple helix formation and no longer reactive with Goodpasture autoantibodies. Although each tissue expressing Goodpasture antigen displayed a specific mRNA pattern, the complete form was always the most abundant and was present at levels apparently unrelated to whether or not the organ of origin is a potential target in Goodpasture syndrome. Furthermore, the antigen sequence was identical in the kidneys of normal and Goodpasture-affected individuals, and no major differences in the expression of the complete and spliced forms were observed.
Fundación Valenciana de Investigaciones Biomédicas, Instituto de Investigaciones Citológicas, Spain.
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Bernal
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Quinones
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Saus
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D019867:Anti-Glomerular Basement Membrane Disease / Q000235:genetics; D001324:Autoantigens / Q000235:genetics*; D001483:Base Sequence; D002417:Cattle; D003094:Collagen / Q000235:genetics*; D024141:Collagen Type IV; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity; D014158:Transcription, Genetic
D001324:Autoantigens; D024141:Collagen Type IV; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; C057112:type IV collagen alpha3 chain; D003094:Collagen