Plant DrgProteins are Cytoplasmic Small GTPase-ObgHomologue

The Obg/Era proteins of P-loop GTPase superclass are conserved in various prokaryotic and eukaryotic organisms. Some of these proteins are critical regulators of many aspects of basic cellular processes, including ribosome biogenesis, translation and signal transduction. However, a genome-wide overview of the Obg/EraGTPase genes in plants is not available. Recentlystudies on comprehensive genomic analyses of Arabidopsis thaliana identified 11 Obg-Hflx like GTPase genes that are divided into nine families/subfamilies: Archaea-related Drg and Nog1, and Eubacteria-related Obg, EngB, HflX, Era, TrmE, EngA, and EngD. In this study we found that Arabidopsis has 3 (three) Drg homologue proteins, namely AtDrg1-1, AtDrg1-2 and AtDrg1-3. Subcellular localization analysis of Arabidopsis Obg-Hflx homologues revealed that Archaea-derived Drg proteins are mainly targeted to cytoplasm, except Drg1-3 was detected not only in cytoplasm but also in nucleus. Furthermore, based on expression pattern profiling indicates that Drg1-1 and Drg1-2 were expressed constitutively trough plant development. On the other hand, Drg1-3 was detected in dry seed and under stress plant.