DEVELOPMENTAL REGULATION OF DEAD BOX PROTEINS AND CLONING OF PUTATIVERNA HELICASE GENES FROM DICTYOSTELIUM-DISCOIDEUM

RNA secondary structure is essential for RNA function in pre-m RNA spl icing, mRNA translation, ribosome assembly and RNA stability. The invo lvement of DEAD/H RNA helicases in the regulation of these processes h as been demonstrated in some cases. To investigate the repertoire of D EAD box proteins expressed in Dictyostelium discoideum, we used PCR te chniques to clone two cDNAs coding for DEAD box proteins with high sim ilarity to known yeast proteins: Dictyostelium Hel2A is about 45% iden tical to Saccharomyces cerevisiae DBP2 and S. pombe dbp2, the yeast ho mologues of human p68. Dictyostelium Hel2B is about 43% identical to t he S. cerevisiae splicing factor PRP28, but has a different domain at the N-terminus, which is unique for Dictyostelium discoideum. Using a polyclonal antibody directed against a DEAD box peptide we show differ ential expression of three DEAD box proteins during the developmental cycle of Dictyostelium.