dutA RNA functions as an untranslatable RNA in the development of Dictyostelium discoideum

dutA is a gene specifically expressed during the development of Dictyostelium discoideum. Toward understanding its possible role in development, we isolated and characterized the gene and its complete cDNA. We found that dutA is encoded by the nuclear genome as a single copy gene without introns. In addition, the following unique and interesting features of dutA RNA (1322 nt) emerged: (1) it has no sustained ORFs (MAX = 126 nt) (2) it is extremely AU-rich (83%) (3) it contains peculiar sequence motifs (large palindromes, long AU-stretches and GC-clusters) (4) it is localized in the cytoplasm but completely absent from ribosomes. These features suggest that dutA RNA functions without being translated into protein. Disruption of the dutA gene did not cause phenotypic changes, suggesting that the function of dutA is redundant.