UbcD4, a ubiquitin-conjugating enzyme in Drosophila melanogaster expressed in pole cells

The ability to destroy a particular protein at a particular time is central to the regulation of many cellular processes. Selective proteolysis in eukaryotic cells is carried out primarily by the ubiquitin-proteasome pathway. Attachment of a ubiquitin polymer to an unwanted protein causes it to be degraded by the proteasome. Several classes of enzyme, known as E1s, E2s and E3s, control the stepwise formation of a ubiquitin-protein conjugate. The specificity of substrate selection lies with the E2s and E3s. Here we describe the cloning of a Drosophila E2 gene, UbcD4, which is only expressed in embryos. Its expression pattern in stage 10-11 embryos suggests a role in germ cell development. UbcD4 can interact with the polyubiquitin-binding subunit of the proteasome.