NII, New Delhi
Sagar Sengupta is Staff Scientist at National Institute of Immunology, New Delhi. He is a Fellow of all three National Science Academies in India. He is a recipient of the 2011 National Bioscience Award for Career Development by Department of Biotechnology, India. He was member of the Department of Biotechnology Cancer Biology Task Force, the Expert Committee on Promotion and Popularization of Biotechnology, Department of Biotechnology, and the DBT Expert Committee for Twinning RD program for North Eastern Region, in the Medical Biotechnology. His research interests include tumour suppressors and oncogenes, DNA damage response, ubiquitylation and phosphorylation-dependent signalling mechanisms, global regulation of gene expression, mitochondrial replication, and the role of mitochondria in cancer. He was elected Fellow of the Indian Academy of Sciences in 2017.
Session 1E: Inaugural Lectures by Fellows
Deciphering the molecular basis of the tumour suppressor functions is vital to understanding how the process of carcinogenesis is evaded under normal physiological conditions. In eukaryotic cells both the nucleus and the mitochondria encode genetic materials, which when mutated, potentiates the cells to undergo neoplastic transformation, which is the first step towards carcinogenesis. Further, the mitochondrial and nuclear genome inter-regulate each other’s functions during the genome maintenance process. The members of RecQ helicase family of tumour suppressors, exemplified by BLM and RECQL4 helicases, play crucial roles in DNA repair, replication and recombination. BLM helicase regulates DNA repair processes like homologous recombination and stimulates the ATPase and chromatin remodelling, thereby allowing better access to the repair complexes. Phosphorylation and ubiquitylation cascades activate BLM functions during the above processes. Further, BLM can enhance the degradation of multiple pro-carcinogenic oncoproteins and thereby maintains genome stability. RECQL4 is the second known mitochondrial helicase and plays a critical role in maintaining the integrity of the mitochondrial DNA replication. In summary, using a class of caretaker tumour suppressors, the mechanisms of maintenance of genome stability have been elucidated. The results have shown how the nuclear and mitochondrial genomes are both required to maintain genomic integrity.