Seminar by Prof. Thomas W. Holstein -"Molecular Mechanisms of Hydra Regeneration"

Speaker:
Prof. Thomas W. Holstein
Molecular Evolution and Genomics,
Centre for Organismal Studies (COS) Heidelberg,
Heidelberg University,
Germany

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Date: Monday, February 21, 2016
Time: 10:30am – 11:30am
Venue: C210, Center Building, Level C
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The freshwater polyp Hydra is famous for its almost unlimited regeneration capacity and immortality. Similar to plants, these features are related to the asexual mode of reproduction of these ancient animals. Hydra exhibits two major stem cell systems: epithelial and interstitial stem cells. The cellular basis for Hydra’s regeneration is an epithelial stem cell system. We study the mechanisms that are responsible for the continuous self-renewal capacity of Hydra stem cells and the recruitment of stem cells during regeneration and under conditions of de novo pattern formation from clusters of dissociated single cells. Our overall objective is to understand the mechanisms controlling stem cell recruitment and regeneration.

By complimentary functional and proteomic approaches, we analyze the contribution of Wnt and TGF-β signaling pathways. Our data on the kinetics of Wnt gene expression in intact and regenerating animals revealed a cascade of consecutive Wnt activation with Wnt3 at the top of the cascade. Using transgenesis and functional assays (siRNA, CRISPR/Cas9) we investigate this autocatalytic regulatory network in the organizer. On the cellular level, we established a new microfluidic assay enabling long-term analysis of re-aggregates and regenerates in vivo.

With respect to these new data and the highly conserved molecular toolkit between Hydra and human the principals of the regeneration process in animal evolution will be discussed. Hydra can provide important insights into the principles of cellular senescence, lineage programming and reprogramming.
 

See more from our lab:
[1] Petersen et al., Mol Biol Evol 32: 1928 (2015).
[2] H. Watanabe et al., Nature 515, 112 (2014).
[3] T.W. Holstein, Cold Spring Harb Perspect Biol; cshperspect.a007922 (2012).
[4] Y. Nakamura, et al. PNAS 108: 9137 (2011).
[5] J.A. Chapman et al. Nature 464: 592 (2010).
[6] I. Philipp, et al., PNAS 106: 4290 (2009).
[7] F. Rentzsch et al., PNAS 104: 3249 (2007).
[8] U. Technau et al., PNAS 97: 12127 (2000).
[9] B. Hobmayer et al. Nature 407:186 (2000).