Identification of a cDNA clone encoding DIP1-binding protein in Drosophila melanogaster

The Drosophila melanogaster L27a gene encodes a ribosomal protein which is a member of the L15 family of ribosomal proteins. D.m. L27a is closely related to the mammalian protein that has been found differentially expressed in lung cancer tissues and therefore could be involved in the control of cell proliferation such as the ribosomal protein S6. Our work elucidates the role of DIP1 which is a novel protein that we found in Drosophila. We performed a two-hybrid system assay and identified the L27a protein as an interactor of DIP1. The interaction was then validated by in vitro binding assays. DIP1, similar to other nuclear proteins in eukaryotes, is localized to the nuclear periphery and chromatin domain in all nuclei, but disappears at the metaphase. It is possible that in D.m. L27a protein, via interaction with DIP1, could be involved in protein synthesis as well as in cell cycle regulation.