NUCLEOTIDE-SEQUENCE OF UB52 FROM THE CNIDARIAN ACROPORA-MILLEPORA REVEALS HIGH EVOLUTIONARY CONSERVATION

We report the cDNA sequence encoding Ub52 from the cnidarian Acropora millepora. As in other eukaryotes, the N-terminal region of the deduce d amino-acid sequence is a ubiquitin moiety and the C-terminal region CEP52, a protein component of the large ribosomal subunit. A. millepor a Ub52 is highly homologous (>95% identical) with the corresponding Dr osophila and vertebrate sequences, the cnidarian sequence having highe r identity with these 'higher' metazoan homologs than does the corresp onding Caenorhabditis elegans protein. However, the cnidarian sequence contains two unique substitutions in the ubiquitin moiety, Ser(22) an d Thr(28). Northern analysis indicates that A. millepora Ub52 is encod ed by a small (<800 nt) mRNA present in eggs and is first expressed af ter the early gastrula stage in embryonic development.