Paul Collodi's Main Page
We are using the zebrafish as a model to study the genetic and extracellular factors that control germ cell formation during development. The rapidly developing and optically clear zebrafish embryos along with methods that are available for conveniently creating transgenic lines of fish make the zebrafish an excellent model for this research. We are using a combination of in vivo and cell culture approaches employing several transgenic lines of fish that express fluorescent proteins and drug resistance specifically in the germ cell lineage. To investigate the factors that control germ cell differentiation, we have established a method to isolate and culture germ line stem cells that are obtained from the gonads of adult male and female fish. In culture, the germ line stem cells respond to individual recombinant zebrafish growth and differentiation factors that are added to the medium enabling in vitro studies of germ cell differentiation. Also, after several weeks in culture, the stem cells can be transplanted into recipient larvae where they proliferate and colonize the host gonad at a high frequency and produce functional gametes in the adult chimeric fish. The stem cell cultures could provide a strategy for stem cell-mediated gene transfer in zebrafish.
In related work, our studies of fish germ cell formation have led to a strategy for introducing an inducible sterility trait into large populations of fish. Sterility is induced by blocking the normal migration of the germ cells in the fish embryo resulting in the production of physiologically normal but infertile adult fish. This method of inducible sterility may provide a strategy for the genetic containment of aquatic species that are used in the aquaculture and pet industries.
Wong, T.T., Tesfamichael, A. and Collodi, P. (2013) Efficient Production of Zebrafish Offspring from Cultured Female Germline Stem Cells. PlosOne (in press)
Wong, T.T., Tesfamichael, A. and Collodi, P. (2013) Identification of Promoter Elements Responsible for Gonad-Specific Expression of Zebrafish Deadend and Its Application to Ovarian Germ Cell Derivation. International Journal of Developmental Biology (in press)
Wong, T.T. and Collodi, P. (2013) Effects of Specific and Prolonged Expression of Zebrafish Growth Factors, Fgf2 and Lif in Primordial Germ Cells in vivo. Biochem. Biophys. Res. Commun. 430, 347-351.
Wong,TT, Saito,T, Crodian, J. and Collodi, P. (2011) Zebrafish Germline Chimeras Produced by Transplantation of Ovarian Germ Cells into Sterile Host Larvae. Biology of Reproduction. 84, 1190-1197.
Liu, W. and Collodi, P. (2010) A zebrafish cell culture assay for the identification of microRNA targets. Zebrafish 4, 343-348.
Liu, W. and Collodi, P. (2010) Zebrafish dead end possesses ATPase activity that is required for primordial germ cell development. FASEB J. 24, 2641-2650.