Characterization of novel hY RNA- and La-associated proteins

Ro ribonucleoprotein particles (Ro RNPs) belong to the family of the small cytoplasmic RNA-protein complexes. In human cells the RNA component of a Ro RNP consists of one of the four hY RNAs designated hY1, hY3, hY4 and hY5. These RNAs are associated with the Ro60 protein and the La protein. Furthermore, hnRNP I has been shown to be associated with hY1 and hY3 RNPs and RoBPI has been reported to associate with hY5 RNPs. In addition, the association of Ro52, calreticulin and hnRNP K with (subsets of) the Ro RNPs has been suggested but is still uncertain. Despite the large body of experimental data collected in the last decade, as yet no biochemical function could be assigned to these complexes. The aim of the studies described in this thesis was to identify novel proteins that are capable to associate (temporarily) with the human Ro RNPs. Such data might contribute to the elucidation of the function(s) of these enigmatic particles. Because the core proteins of Ro RNPs are expected to play an important role in such interactions, we also analyzed the Ro60 protein in more detai