Christian P. Petersen Associate Professor of Molecular Biosciences

Research Interests

Regeneration is widespread in nature but poorly understood due to the underrepresentation of regenerative abilities among most model organisms. Regenerating animals are confronted with unique challenges that defy explanation—production of fully differentiated structures starting from an adult rather than embryonic context, integration of newly regenerated and previously existing tissues, and specification of the identity of regenerating tissues. What molecular and cellular processes do regenerating animals use to solve these problems? We are addressing these problems by turning to an animal model that possesses almost unlimited regenerative abilities, the planarian Schmidtea mediterranea. These animals possess stem cells of high potency, termed neoblasts, as well as finely tuned regulatory systems that enable them to replace any adult tissue removed by injury, including after decapitation, and also replace old tissues continually to attain indefinite lifespans. They can be reared in large numbers and probed by functional genomics and whole-animal histology to unravel the molecular basis for regenerative abilities.

We have investigated the biology of this organism to define the critical regulators, pathways, and principles underlying the molecular and developmental biology of regeneration. Our ongoing efforts address several major fundamental questions in regeneration biology that are as-yet unanswered: How do regenerating animals “know” what tissues are damaged or missing?  What triggers regenerative outgrowth?  How do regenerating animals control the extent and scale of growth? Is it possible to enhance regenerative repair? We have discovered that regeneration involves the use of stem cells to produce tissue organizing centers necessary for regenerative outgrowth, it requires long-range signaling that specifies the identity of tissues present/absent after injury, it uses spatial feedback inhibition to determine the extent of the regeneration response.  In addition, we have begun to define pathways that control stem cell abundance, that assemble progenitors into functional tissues, and that act to limit regenerative ability.  Regenerative processes are likely to be ancient and conserved, and therefore elucidating mechanisms governing extreme regeneration can identify targets for the enhancement of human tissue repair as well as inform future efforts to produce organs synthetically.

Selected Publications

Integrin suppresses neurogenesis and regulates brain tissue assembly in planarian regenerationBonar NA and Petersen CP. Development. 2017 March 1;144(5):784-794.

The NuRD complex component p66 suppresses photoreceptor neuron regeneration in planariansVásquez-Doorman C and Petersen CP. Regeneration. 2016 August 18;3(3):168-178.

Wnt, Ptk7, and FGFRL expression gradients control trunk positional identity in planarian regenerationLander R and Petersen CP. eLife. 2016 April 13;5:e12850.

Wnt/Notum spatial feedback inhibition controls neoblast differentiation to regulate reversible growth of the planarian brainHill EM and Petersen CP. Development. 2015 December 15;142(24):4217-4229.

teashirt is required for head-versus-tail regeneration polarity in planarians. Owen JH, Wagner DE, Chen C-C, Petersen CP, and Reddien PW. Development. 2015 March 15;142(6):1062-1072.

Planarian Resistance to Blades and BugsPetersen CP. Cell Host & Microbe. 2014 September 10;16(3):271-272.

zic-1 Expression in Planarian Neoblasts after Injury Controls Anterior Pole RegenerationVásquez-Doorman C and Petersen CP. PLoS Genetics. 2014 July 3;10(7):e1004452.

Polarized notum Activation at Wounds Inhibits Wnt Function to Promote Planarian Head RegenerationPetersen CP and Reddien PW. Science. 2011 May 13;332(6031):852-855.

Wnt Signaling and the Polarity of the Primary Body AxisPetersen CP and Reddien PW. Cell. 2009 December 11;139(6):1056-1068.

A wound-induced Wnt expression program controls planarian regeneration polarityPetersen CP and Reddien PW. PNAS. 2009 October 6;106(40):17061-17066.

Smed-βcatenin-1 Is Required for Anteroposterior Blastema Polarity in Planarian RegenerationPetersen CP and Reddien PW. Science. 2008 January 18;319(5861):327-330.

14-3-3σ controls mitotic translation to facilitate cytokinesis. Wilker EW, van Vugt MATM, Artim SC, Huang PH, Petersen CP, Reinhardt HC, Feng Y, Sharp PA, Sonenberg N, White FM, and Yaffe MB. Nature. 2007 March 15;446(7133):329-332.

Short RNAs Repress Translation after Initiation in Mammalian CellsPetersen CP, Bordeleau M-E, Pelletier J, and Sharp PA. Molecular Cell. 2006 February 17;21(4):533-542.

View all publications by Christian P. Petersen listed in the National Library of Medicine (PubMed). Current and former IBiS students in blue.