Molecular cloning of the cDNA encoding the constant region of the immunoglobulin A heavy chain (C α) from a marsupial: Trichosurus vulpecula (common brushtail possum)

Abstract

A cDNA encoding the brushtail possum immunoglobulin A heavy chain constant region (C α) was isolated by screening a mesenteric lymph node cDNA library with a porcine C α exon 3 probe. The larger of the two positive clones isolated (Tv4a) consisted of 1325 bp of possum cDNA that included an open reading frame of 1191 bp. Its deduced amino acid sequence had a high degree of sequence identity with known eutherian C α sequences. This clone appears to encode the entire possum IgA heavy chain constant region. The possum C α sequence had a nucleotide sequence identity of 57.7% with porcine C α, 51% with mouse C α, 46.7% with dog C α and 45.9% with human C α2. The corresponding amino acid identities were 46.7, 45.6, 49.4 and 49%, respectively.