DFRP PROTEINS REGULATING DRG PROTEINS AND UTILIZATION OF THE SAME

摘要

Novel DRG family regulatory proteins DFRP1 and DFRP2 are identified. In a transient transduction test, DFRP1 binds specifically to DRG1 while DFRP2 binds mainly to DRG2. DFRPs block polyubiquitination seemingly occurring prior to the decomposition of the DRG proteins and thus stabilize the target DRG proteins due to physical bindings. DFRPs are highly conserved in eukaryotes. The expression patterns of dfrp1 and drg1 transcription products in the embryo and tissue of Xenopus are similar to each other, which indicates that these genes synergistically act in eukaryotic cells of various types. As the results of an immunofluorescent test, it is clarified that the interaction between DRG1 and DFRP1 would likely arise in the cytoplasm. By constructing a dfrp1-knockout cell, it is found out that the internal expression of DRG1 is regulated by DFRP1. Namely, it is confirmed that DFRP1 is a DRG1-specific up regulator in vivo. Based on these results, it is proposed that DRG1 and DRG2 are regulated in different manners, though they are close to each other in structure.