1.Æ¯°Á¦¸ñ : The planarian Schmidtea mediterranea is a model to dissect complex regenerative processes in animals.
2.¿¬ ÀÚ : Alejandro Sánchez Alvarado, Ph.D.
3.¼Ò ¼Ó : Howard Hughes Medical Institute, Department of Neurobiology & Anatomy University of Utah School of Medicine, Slat Lake City, UT, USA
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6.³» ¿ë : The problem of regeneration is fundamentally a problem of tissue homeostasis that involves either the replacement of cells due to normal ¡°wear and tear¡± (cell turnover), or the replacement of cells after injury. This is particularly significant for organisms possessing relatively long life spans, in which maintenance of all body parts and their functional integration is required for many years in order for the individual to thrive. Thus, the replacement of differentiated cells is a major challenge all multicellular organisms must face. For almost 10 years now, we have pursued our studies from the postulate that a scientific understanding of the basic principles of complex regenerative phenomena necessitates reducing such complexity into a high-ordered system that is, nevertheless, amenable to direct and extensive experimental interrogation. We have found such a system in the freshwater, non-parasitic flatworm Schmidteamediterranea. This animal possesses all three germ layers (ecto-, endo- and mesoderm), is diploid (4 pairs of chromosomes with a genome size of ~800Mb), and displays remarkable regenerative capacities. We have developed a number of methods to investigate the biological attributes of S.mediterraneaandarecurrentlydefiningtheextentofevolutionaryconservationthatexistsbetweentheseanimalsandothermedicallyrelevantmodelsystemssuchasDrosophilamelanogaster,Caenorhabditiselegans,miceandhumans. More importantly, we are presently using S.mediterraneaas a gene discovery tool to identify molecules and conditions that promote regeneration, as well as the regulatory networks that control this process. Our overarching aim is to delineate the molecular and cellular conditions capable of either promoting or inhibiting regeneration in animals. I will present a summary of the molecular and bioinformatics tools we have developed thus far; what we have found by applying such tools to interrogate planarian biology; and what we are presently trying to ultimately reach our goal.
7. FIVE MOST IMPORTANT PUBLICATIONS (Dr. Sanchez)
1) Jason Pellettieri and Alejandro Sánchez Alvarado (2007). Regeneration and Tissue Homeostasis. Annual Review of Genetics, Vol. 41, in press.
2) Alejandro Sánchez Alvarado and Panagiotis A. Tsonis (2006). Bridging the regeneration gap: Genetic insights from diverse animal models. Nature Reviews Genetics, 7: 873-884.
3) Alejandro Sánchez Alvarado (2006). Planarian regeneration: its end is its beginning. Cell, 124: 241-5.
4) Peter Reddien, Néstor J. Oviedo, Joya R. Jennings, James C. Jenkin, and Alejandro Sánchez Alvarado (2005). SMEDWI-2 is a PIWI-like protein that regulates planarian stem cells. Science, 310:1327-1330.
5) Peter Reddien, Adam Bermange, Kenneth Murfitt, Joya R. Jennings, and Alejandro Sánchez Alvarado (2005). RNAi screening identifies regeneration and stem cell regulators in the planarian Schmidtea mediterranea. Developmental Cell, 5: 635-49.