Synthesis of small nuclear ribonucleoprotein particles by the malarial parasite Plasmodium falciparum.

Sera from patients with autoimmune diseases have been used to identify small nuclear ribonucleoprotein particles (snRNPs) present in higher eukaryotic cells and also in dinoflagellates. Previously these sera have not detected crossreactive snRNP protein antigens of other lower eukaryotes such as yeast, Tetrahymena, or Dictyostelium. We report that anti-Sm, anti-U1-RNP, and anti-La/SS-B human antisera react with specific snRNP protein antigens synthesized by the protozoan Plasmodium falciparum, the human malarial parasite. These results suggest that the structure and antigenicity (and thus probably the function) of snRNPs have been widely conserved in eukaryote evolution.