Research Projects

Mediator is a multi-subunit protein complex that acts as an intermediate component to integrate information from transcription factors (TFs) towards RNA Pol II in eukaryotes (Flanagan et al., 1991). Most of the TFs do not interact with RNA Pol II directly, thus they sometimes require Mediator complex for transcription. The subunits of the Mediator complex are arranged in four modules termed as Head, Middle, Tail and a dissociable Kinase module (Tsai et al., 2014). Generally, the head module interacts with RNA Pol II and general TFs, the middle module acts as a connecting link between head and tail module, the tail module conveys information from myriad of TFs and the Kinase module plays a regulatory role by repressing transcription via blocking the interaction of Mediator with RNA Poll II or by activating transcription through phosphorylation of important proteins including histones (Ansari and Morse, 2013). The basic principle of Mediator functioning relies upon the protein-protein interaction between the individual subunits and plethora of other proteins including TFs, which helps Mediator to affect most of the transcription-related processes such as transcription initiation, elongation, pausing, chromatin remodeling etc. (Allen and Taatjes, 2015; Richter et al., 2022). The functional characterization of various Mediator subunits in plants have suggested their roles in developmental processes such as embryo development, flowering, root development, organ size determination, mineral homeostasis and biotic/abiotic stress tolerance. In last 16 years, multiple studies from the host lab have contributed significantly in understanding the structure and functions of Mediator complex and its subunits in yeast and plants (Agrawal et al., 2023, 2022; Dwivedi et al., 2019; Maji et al., 2024, 2019; Thakur et al., 2014; Waseem et al., 2023). Therefore, host lab has got all the expertise required to study the structural and functional details of the plant Mediator complex. The major advances to our knowledge regarding the protein interactions by Mediator subunits have come through the research work in yeast and animal models (Allen and Taatjes, 2015). However, higher plants harbour a different set of plant-specific TFs (such as NAC, WRKY etc) which are different from fungal-specific and metazoan-specific TFs. These plant-specific TFs are known to regulate important agronomic traits (Dwivedi et al., 2019). Attempts to isolate the Mediator complex under in vitro conditions can aid to gain knowledge upon its interaction with various TFs. Earlier, the host lab has derived topological model of Mediator complex from Arabidopsis thaliana based on map generated by using interaction studies and computational modelling (Maji et al., 2019). Through the current project, we want to perform in vitro purification of the rice Mediator complex under different conditions – normal versus higher ambient temperature for its detailed characterization.