Department of Biology
email: ramkumars (at) iisertirupati.ac.in
Our laboratory studies the mechanisms regulating vertebrate embryonic development. Mesoderm, one of the three primordial cell layers in the embryo, generates a variety of cell types in order give rise to a number of tissues and organs such as heart, muscle, bone, blood, kidney etc. We focus on mechanisms that underlie the diversification of mesoderm into various cell types.
Another major interest in our laboratory is to study the development of neural crest cells. Neural crest cells emerge relatively late during development, yet possess extraordinary differentiation potential comparable to the primordial cell layers. We focus on the mechanisms that underlie this unusual developmental potential of neural crest.
Knowledge of developmental mechanisms is key to develop strategies for guiding the differentiation of pluripotent stem cells into cell types of choice. Leveraging the outcome of our studies, we develop strategies for guiding the differentiation of pluripotent stem cells, such as human embryonic stem cells, into clinically relevant cell types. Generating specific cell types in the dish allows us to mimic diseases affecting these cell types in the laboratory  and thus, to study the disease mechanism. Our laboratory has uncovered the mechanism specifying the cardiopharyngeal mesoderm, which gives rise to the heart and the skeletal muscles of the head. Exploiting this knowledge, we are working towards modelling dystrophies involving head muscles. Similarly, we are also addressing the disease mechanism of Saethre-Chotzen syndrome, characterised by craniofacial abnormalities, involving neural crest developmental defects.
The cardiopharyngeal mesoderm is an embryonic tissue of evolutionary importance. Its derivatives, the heart and the head muscles such as jaw muscles, confer efficient metabolism and predatory behaviour, respectively. Therefore, this mesoderm subtype is considered key for the evolution of predatory lifestyle in vertebrates. Notably, how cardiopharyngeal mesoderm itself emerged during evolution remains an open question. Taking the lead from our findings on the developmental mechanism of this mesoderm subtype, we are addressing its evolutionary origin.
In essence, our laboratory's program is anchored in developmental biology. The avenues created by this enterprise allows us to tackle evolution and human disease.
Education and career
- Nandkishore N*, Vyas B*, Javali A, Sambasivan R. Early mesoderm specification underlies divergent head and trunk muscle development in vertebrates. Development. 2018 Sep 20;145(18). Doi: 10.1242/dev.160945
- Rajasekaran S, Thatte J, Periasamy J, Jayaram M, Jayandharan GR, Sambasivan R. Infectivity of AAV serotypes in mouse testis. BMC Biotech. 2018 Nov 1;18(1):70. Doi: 10.1186/212896-018-0479-1
- Javali A*, Misra A*, Leonavicius K, Acharyya D, Vyas B, Sambasivan R. Co-expression of Tbx6 and Sox2 identifies a novel transient neuromesoderm progenitor cell state. Development. 2017 Dec 15;144(24):4522-4529. Doi: 10.1242/dev.153262.
- Comai G*, Sambasivan R*, Gopalakrishnan S, Tajbakhsh, S. Variations in the efficiency of lineage marking and ablation confound distinctions between myogenic cell populations, Dev Cell, 2014 Dec 8;31(5):654-67. doi: 10.1016/j.devcel.2014.11.005. *Equal first authors
- Sambasivan R*, Yao R*, Kissenpfennig A, Van Wittenberghe L, Paldi A, Gayraud-Morel B, Guenou H, Malissen B, Tajbakhsh S, Galy A. Pax7-expressing satellite cells are indispensable for adult skeletal muscle regeneration. Development. 2011 Sep;138(17):3647-56. doi: 10.1242/dev.067587. * Equal authors
- Sambasivan R, Kuratani S, Tajbakhsh S. An eye on the head: the development and evolution of craniofacial muscles. Development. 2011 Jun;138(12):2401-15. doi: 10.1242/dev.040972. Review.
- Sambasivan R, Cheedipudi S, Pasupuleti N, Saleh A, Pavlath GK, Dhawan J. The small chromatin-binding protein p8 coordinates the association of anti-proliferative and pro-myogenic proteins at the myogenin promoter. J Cell Sci. 2009 Oct 1;122(Pt 19):3481-91. doi: 10.1242/jcs.048678.
- Sambasivan R, Gayraud-Morel B, Dumas G, Cimper C, Paisant S, Kelly RG, Tajbakhsh S. Distinct regulatory cascades govern extraocular and pharyngeal arch muscle progenitor cell fates. Dev Cell. 2009 Jun;16(6):810-21. doi: 10.1016/j.devcel.2009.05.008.
Open positionsPlease note that I would like to indicate that there are Open Positions for
- Ph.D. students (Application uniquely through the IISER Ph.D. program)