The nuclear autoantigen La/SS-B: mapping and sequencing of the gene and the three retropseudogenes

• Published in: Gene 1997-05, Vol.191 (1), p.23-29
• Main Authors: Grölz, Daniel, Bartsch, Holger, Tröster, Helmut, Bachmann, Michael
• Format: Article
• Language: English
• Subjects: Autoantigens - genetics; Autoimmunity; Base Sequence; Cell Nucleus - metabolism; Chromosome Mapping; DNA, Complementary; Evolution, Molecular; Exons; Hot spot; Humans; La/SS-B gene; Molecular Sequence Data; Mutation; Neoepitope; Pseudogene; Pseudogenes; Ribonucleoproteins - genetics; SS-B Antigen
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/S0378-1119(97)00023-1

One target of autoantibodies in sera of patients with systemic lupus erythematosus or primary Sjögren's syndrome is the nuclear autoantigen La/SS-B. Lambda clones and cosmids were isolated, which contained the sequences of the La gene and the three La pseudogenes. They were used for preparation of a physical map. Finally, the La gene and pseudogenes were sequenced. The pseudogenes were characterized as retropseudogenes. Their evolutionary ages were estimated to be approx. 4, 4.5 and 5 million years. Inserts of 4, 16 and 24 nucleotides, which were mostly A-residues, were found in exon 7 of the respective pseudogene. The oldest pseudogene contained the longest insert, the youngest pseudogene contained the smallest insert. The oligonucleotides seem to be the result of repeated inserts of A-residues in a hot spot region of the La genes. Two La cDNAs were isolated which contained either a deletion or an insert of an A-residue at the same position.