Ranjan Sen obtained his Ph. D. degree (1996) in Biophysics and Molecular Biology from Calcutta University.  He worked on conformational changes of E.coli RNA polymerase during transcription initiation in the laboratory of Dipak Dasgupta, Saha Institute of Nuclear Physics, Calcutta.  He then moved to National Institute of Genetics, Mishima, Japan to work in the laboratory of Nobuo Shimamoto as a postdoctoral fellow.  There he worked (1995-1998) on kinetics of abortive transcription in prokaryotes and established a concept of branched pathway during transcription initiation process.  He subsequently moved to National Institutes of Health, Bethesda, MD, USA for his second postdoctoral work in the laboratory of Robert Weisberg.  Here he worked (1998-2001) on the mechanism of transcription antitermination by an antiterminator RNA, the PUT RNA.  He showed the direct and persistent interaction of the nascent RNA (the PUT RNA) with the elongating RNA polymerse which leads to the stabilization RNA/DNA hybrid at the active site of the enzyme. His laboratory at CDFD is operational from 2002.