Sequence of a Drosophila cDNA encoding a ubiquitin gene fusion to a 52- aa ribosomal protein tail

In Drosophila, ubiquitin belongs to a gene family. Two members of this family have been previously described (1, 2). We report here the nucleotide sequence of a third member isolated by screening a cDNA Drosophila melanogaster library with Drosophila polyubiquitin gene as a probe. It encodes a full-length ubiquitin monomer with a 52-aa extension protein. Recently this extension has been shown to encode for a ribosomal protein (3). Comparing the moiety ubiquitin aa sequence with homologous ones from human (4), Chlamydomonas (5) and yeast (6) shows no aa substitutions from human counterpart. The extension (from the arrow) is also very conserved, showing 4 conservative out of 5 total substitutions from the evolutionarily distant yeast. ACKNOWLEDGEMENTS