Regional Centre for Biotechnology, Faridabad Faridabad, Haryana, India
Body of Abstract: ABSTRACT
In the cell, mRNAs are translated by ribosome however; under stress protein synthesis is affected. Ribosome constitutes of 45 large (RPL) and 32 small proteins (RPS) and biogenesis and assembly is a complex process. The ribosomal proteins are affected under stress conditions and plants have multiple copies suggesting heterogeneous ribosomes. We report, the role of rice ribosomal protein RPL10, which is induced in multiple stresses including drought. In rice, RPL10 has multiple genes RPL10A1, RPL10A2, RPL10B.1, B.3, B.4 and RPL10C. Each RPL10 gene localizes to different organelles. RPL10A1 localize to chloroplast, RPL10A2 to mitochondria and RPL10B and its alternative forms to nucleus and RPL10C to nucleolus suggesting their involvement in different organelle translation. To understand RPL10’s extra-ribosomal functions several interacting proteins has been identified in Y2H screen. RPL10B was found to interact with C3H-ZF transcription factor (TF) and other ribosome biogenesis factors. Inplanta confocal studies confirmed their interactions in nucleolus. Since C3H-ZF known to bind to the promoter of MEL1 gene encoding Argonaute, we cloned the 2 kb promoter of MEL1 driving GFP to confirm the TF activity through transactivation assay. C3H-ZF represses the transcription of MEL1 driven GFP. However, when RPL10B protein was co-expressed with C3H-ZF showed reactivation of transcription. These results confirm that RPL10B proteins have transcriptional regulation as extra-ribosomal functions. Genetic manipulation in rice further confirms its role in extra-ribosomal functions.