Abstract
Planarian flatworms are carnivorous invertebrates with astounding regenerative properties. They have a ventral surface on which thousands of motile cilia are exposed to the extracellular environment. These beat in a synchronized manner against secreted mucus thereby propelling the animal forward. Similar to the nematode Caenorhabditis elegans, the planarian Schmidtea mediterranea is easy to maintain in the laboratory and is highly amenable to simple RNAi approaches through feeding with dsRNA. The methods are simple and robust, and the level of gene expression reduction that can be obtained is, in many cases, almost total. Moreover, cilia assembly and function is not essential for viability in this organism, as animals readily survive for weeks even with the apparent total absence of this organelle. Both genome and expressed sequence tag databases are available and allow design of vectors to target any desired gene of choice. Combined, these feature make planaria a useful model system in which to examine ciliary assembly and motility, especially in the context of a ciliated epithelium where many organelles beat in a hydrodynamically coupled synchronized manner. In addition, as planaria secrete mucus against which the cilia beat to generate propulsive force, this system may also prove useful for analysis of mucociliary interactions. In this chapter, we provide simple methods to maintain a planarian colony, knockdown gene expression by RNAi, and analyze the resulting animals for whole organism motility as well as ciliary architecture and function.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Mitchell DR (2007) The evolution of eukaryotic cilia and flagella as motile and sensory organelles. Adv Exp Med Biol 607:130–140
King SM, Pazour GJ (2009) Cilia: model organisms and intraflagellar transport. Methods in cell biology, vol 93. Elsevier, Burlington, MA
Witman GB (1986) Isolation of Chlamydomonas flagella and flagellar axonemes. Methods Enzymol 134:280–290
Sears PR, Davis CW, Chua M, Sheehan JK (2011) Mucociliary interactions and mucus dynamics in ciliated human bronchial epithelial cell cultures. Am J Physiol 301:L181–L186
Sawamoto K, Wichterle H, Gonzalez-Perez O, Cholfin JA, Yamada M, Spassky N, Murcia NS, Garcia-Verdugo JM, Marin O, Rubenstein JLR, Tessier-Lavigne M, Okano H, Alvarez-Buylla A (2006) New neurons follow the flow of cerebrospinal fluid in the adult brain. Science 311:629–632
Rink JC (2013) Stem cell systems and regeneration in planaria. Dev Gene Evol 223:67–84
Newmark P, Sanchez-Alvarado A (2002) Not your father's planarian: a classic model enters the era of functional genomics. Nat Rev Genet 3:210–219
Rompolas P, King SM (2009) Schmidtea mediterranea: a model system for analysis of motile cilia. Methods Cell Biol 93:81–98
Azimzadeh J, Wong ML, Downhour DM, Sanchez-Alvarado A, Marshall WF (2012) Centrosome loss in the evolution of planarians. Science 335:461–463
Rink J, Gurley K, Eliot S, Sanchez-Alvarado A (2008) Planarian Hh signaling regulates regeneration polarity and links Hh pathway evolution to cilia. Science 326:1406–1410
Almuedo-Castillo M, Salo E, Adell T (2011) Dishevelled is essential for neural connectivity and planar cell polarity in planarians. Proc Natl Acad Sci U S A 108:2813–2818
Rompolas P, Patel-King RS, King SM (2010) An outer arm dynein conformational switch is required for metachronal synchrony of motile cilia in Planaria. Mol Biol Cell 21:3669–3679
Newmark P, Reddien P, Cebria F, Sanchez-Alvarado A (2003) Ingestion of bacterially expressed double-stranded RNA inhibits gene expression in planaria. Proc Natl Acad Sci U S A 100:11861–11865
Dawar B (1973) A combined relaxing agent and fixative for Triclads (Planarians). Biotech Histochem 48:93–94
Patel-King RS, Gilberti RM, Hom EFY, King SM (2013) WD60/FAP163 is a dynein intermediate chain required for retrograde intraflagellar transport in cilia. Mol Biol Cell 24:2668–2677
Acknowledgement
Our laboratory is supported by grant GM051293 (to S.M.K.) from the National Institutes of Health.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer Science+Business Media New York
About this protocol
Cite this protocol
King, S.M., Patel-King, R.S. (2016). Planaria as a Model System for the Analysis of Ciliary Assembly and Motility. In: Satir, P., Christensen, S. (eds) Cilia. Methods in Molecular Biology, vol 1454. Humana Press, New York, NY. https://doi.org/10.1007/978-1-4939-3789-9_16
Download citation
DOI: https://doi.org/10.1007/978-1-4939-3789-9_16
Published:
Publisher Name: Humana Press, New York, NY
Print ISBN: 978-1-4939-3787-5
Online ISBN: 978-1-4939-3789-9
eBook Packages: Springer Protocols