Abstract
The TREX-2 complex integrates several stages of gene expression, such as transcriptional activation and mRNA export. In D. melanogaster, TREX-2 consists of four major proteins: Xmas-2, ENY2, PCID2, and Sem1p. The Xmas-2 protein is the core subunit of the complex, with which other TREX-2 subunits interact. Xmas-2 homologues were found in all higher eukaryotes. Previously, it was shown that the human Xmas-2 homologue, GANP protein, can undergo cleavage into two parts, probably during apoptosis. We showed that the Xmas-2 protein of D. melanogaster can also split into two fragments. The resulting fragments of the protein correspond to the two large Xmas-2 domains. Protein splitting is observed both in vivo and in vitro. However, Xmas-2 cleavage in D. melanogaster is observed under normal conditions and is probably a part of the mechanism of transcription and mRNA export regulation in D. melanogaster.
