Johan Paulsson is a Swedish mathematician and systems biologist at Harvard Medical School. He is a leading researcher in

systems biology Systems biology is the computational modeling, computational and mathematical analysis and modeling of complex biological systems. It is a biology-based interdisciplinary field of study that focuses on complex interactions within biological syst ...

and

stochastic process In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables. Stochastic processes are widely used as mathematical models of systems and phenomena that appea ...

es, specializing in stochasticity in gene networks and plasmid reproduction.

Biography

Johan Paulsson was born in 1973, in Kristinehamn, a small city in the

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

province of Värmland. He studied at Uppsala University, where he obtained a BSc in Mathematics in 1996, a Masters of Science in Molecular Biology in 1996, and a Ph.D. in Molecular Biology in 2000 on stochasticity in intracellular circuits, in particular in plasmid copy control, under the supervision of Profs. Mans Ehrenberg and Kurt Nordström. In 2000 he moved to Princeton University, where he was a Lewis-Thomas Fellow in Biophysics, where he did the research for his paper "Summing up the noise in genetic networks", which received wide attention because it gave a firm theoretical footing to the budding field of genetic noise. In 2003 he joined the Dept. of Applied Mathematics and Theoretical Physics at the University of Cambridge and was tenured the following year. In 2005 he moved to the recently created Department of Systems Biology at

Harvard Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

University, where he focused on the development of experimental techniques for counting plasmids in single cells and on theoretical results on control of fluctuations in gene expression. He is married with two children.

Work

Paulsson's lab has made major contributions to the development of experimental techniques for counting plasmids, to extend his previous work on the mathematical aspects of plasmid replication as well as theoretical work on the stochastic processes on gene expression and copy number control and work on multi-level selection by using experimental evolution. His most influential publication is the analysis of all previous noise data and interpretations in one unified framework, which later guided many experimental approaches. More recent results include the effects of partition in phenotypic variability, the details of the stochastic processes that underlie gene expression noise and the limitations of the usual experimental approaches and the fundamental limits of feedback as a noise control mechanism. This set of interests led Paulsson to examine the

repressilator The repressilator is a genetic regulatory network consisting of at least one feedback loop with at least three genes, each expressing a protein that represses the next gene in the loop. In biological research, repressilators have been used to buil ...

, a synthetic gene regulatory network that was designed from scratch to oscillate and reported in 2000A Synthetic Oscillatory Network of Transcriptional Regulators;

Michael Elowitz Michael B. Elowitz is a biologist and professor of Biology, Bioengineering, and Applied Physics at the California Institute of Technology, and investigator at the Howard Hughes Medical Institute. In 2007 he was the recipient of the Genius gran ...

and

Stanislas Leibler Stanislas Leibler (born 1957) is a French-American theoretical and experimental biologist and physicist. He is Systems Biology Professor at the Institute for Advanced Study in Princeton and the Gladys T. Perkin Professor and Head of the Laboratory ...

; Nature. 2000 Jan 20;403(6767):335-8. by

and

. Although the repressilator oscillated, and therefore demonstrated the potential of synthetic biology, the oscillations were noisy and quickly became incoherent on the single cell level. Using an understanding of the causes of noise in cellular networks, Paulsson's team was able to redesign the repressilator, retaining the basic design, to produce a new synthetic circuit that oscillated with unprecedented accuracy

References

External links

Johan Paulsson's Lab @ HMS

Johan Paulsson's Faculty Profile @ HMS
{{DEFAULTSORT:Paulsson, Johan Harvard Medical School faculty Living people Probability theorists Swedish biologists Swedish biophysicists Systems biologists Uppsala University alumni Year of birth missing (living people)