The genetic information encoded in DNA is read off in living cells through the processes of 'transcription' and 'translation.' The gene produces mRNA molecules (transcription), and mRNAs make proteins (translation) using other macromolecules' help. One fact of life is that these molecular processes are 'noisy.' There are cell-to-cell variations in the mRNA and protein copy numbers even when cells are genetically identical. This noise arguably is a source of 'phenotypic diversity'. We are interested in how molecular regulation affects gene expression noise.
Previously we investigated how molecular competition for transcription factors affects gene expression noise. We are now looking at post-transcriptional regulation of the gene expression by micro-RNAs. Micro-RNAs are small non-coding RNAs that bind to large mRNA molecules and inhibit translation. We are developing stochastic models for micro-RNA mediated negative feedback loops.
Theoretical & Physical Biology Group
Size regulation and kinetics of subcellular structures
Subcellular structures (organelles) such as Golgi bodies, Vesicles, cytoskeletal filaments (e.g. microtubules and actin filaments), etc., come with a remarkable variety of shapes and sizes. We are interested to know how the sizes and numbers of these structures in a cell are controlled. In line with this general interest, we are investigating how biofilaments' length distributions are affected by a limiting pool of molecular build-blocks. The pool can be either homogeneous or heterogeneous. Previously, we explored how multiple biofilaments collectively generate forces through polymerization when they grow against a rigid membrane. Such forces help a cell to migrate.
Main papers on this topic
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Cell-to-cell variability in organelle abundance reveals mechanisms of organelle biogenesis, S Choubey, D Das, S Majumdar, Physical Review E 100, 2019.
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Sufficient conditions for the additivity of stall forces generated by multiple filaments or motors, T Bameta, D Das, D Das, R Padinhateeri, MM Inamdar, Phys. Rev. E 95, 2015.
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Collective force generated by multiple biofilaments can exceed the sum of forces due to individual ones, D Das, D Das, R Padinhateeri, New J. Phys. 16, 2014.