INTERACTION OF THE LA (SS-B) AUTOANTIGEN WITH SMALL RIBOSOMAL-SUBUNITS

The La (SS-B) autoantigen is an evolutionarily conserved 47-kDa protei n which binds to nascent RNA polymerase III transcripts and to a numbe r of viral leader RNAs. The La protein plays a direct role in the term ination of RNA polymerase III transcription and recent findings have s uggested an additional role in several aspects of translation of (vira l) messenger RNAs. Here, we show that La in the cytoplasm is associate d with a subset of small ribosomal subunits, possibly by direct associ ation with 18S ribosomal RNA. This association is likely to be related to the putative role of this protein in translation regulation.