Exosome Component 9 (EXOSC9)

Antinucleolar antibodies are found in patients with scleroderma or polymyositis or in patients with overlap of these 2 syndromes. The 2 most prominent proteins in this PMSCL autoantigen complex, PMSCL1 and PMSCL2, are detected as 75- and 100-kD molecules, respectively. The deduced 355-amino acid protein contains a high proportion of charged residues at its C terminus, including a string suggestive of a nuclear or nucleolar localization signal. Northern blot analysis revealed expression of a 1.6-kb PMSCL1 transcript in 2 leukemia cell lines. SDS-PAGE and immunoblot analysis showed that the recombinant protein is expressed at a size close to that of the native protein, which is considerably higher than the predicted size of 39 kD, probably due to acidic residues at the C terminus.