The major objective of this proposal is to elucidate the lineage relationships between the different cell types in the developing limb and heart. Lineage relationships in the limb will be determined in the chick using a powerful technique involving injection of embryonic progenitors with a library of retroviral vectors. Each vector carries a distinct """"""""tag"""""""" and subsequent PCR sequencing of the tag from injected cells is used to define individual cells in the later limb bud or mature limb that are clonally related. Critical questions to be addressed by this analysis in the limb include the timing of specification and lineage relationships of various cell types within the limb bud, whether there are distinct dorsal and ventral compartments in the limb bud, and the time when proximodistal limb segments are specified within the limb bud. We will also conduct an analysis of the lineages contributing to various portions of the valves of the heart. Heart valves are currently thought to derive from delanination of the endocardium, forming a precursor population called the cardiac cushion. However, we have indications that the cushions may form from 3 distinct cell populations, each with different fate in the mature valve. This will be tested using recombinase-based fate mapping in mouse embryos. In addition to addressing specific questions in limb and heart development, these studies will provide an important context for designing future experiments. Finally, the reagents generated in these studies will also allow us to definitely test whether the tendon and cartilage precursors in the limb bud are dedicated progenitors or whether they contribute to other cell types in the limb. Moreover, the same reagents will be used to test whether Hox gene expression is required autonomously in the tendon and skeletal progenitors for proper patterning of the limb.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
1R01HD045499-01A2
Application #
6964953
Study Section
Development - 1 Study Section (DEV)
Program Officer
Javois, Lorette Claire
Project Start
2005-08-10
Project End
2010-05-30
Budget Start
2005-08-10
Budget End
2006-05-30
Support Year
1
Fiscal Year
2005
Total Cost
$427,447
Indirect Cost
Name
Harvard University
Department
Genetics
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Lehoczky, Jessica A; Tabin, Clifford J (2015) Lgr6 marks nail stem cells and is required for digit tip regeneration. Proc Natl Acad Sci U S A 112:13249-54
Gros, Jerome; Tabin, Clifford J (2014) Vertebrate limb bud formation is initiated by localized epithelial-to-mesenchymal transition. Science 343:1253-6
Rohner, Nicolas; Tschopp, Patrick; Tabin, Cliff (2014) Development: facial makeup enhancing our looks. Curr Biol 24:R36-R38
Whited, Jessica L; Tsai, Stephanie L; Beier, Kevin T et al. (2013) Pseudotyped retroviruses for infecting axolotl in vivo and in vitro. Development 140:1137-46
Whited, Jessica L; Lehoczky, Jessica A; Tabin, Clifford J (2012) Inducible genetic system for the axolotl. Proc Natl Acad Sci U S A 109:13662-7
Katz, Tamar C; Singh, Manvendra K; Degenhardt, Karl et al. (2012) Distinct compartments of the proepicardial organ give rise to coronary vascular endothelial cells. Dev Cell 22:639-50
Gross, Joshua B; Kerney, Ryan; Hanken, James et al. (2011) Molecular anatomy of the developing limb in the coquí frog, Eleutherodactylus coqui. Evol Dev 13:415-26
Kamei, Caramai N; Kempf, Hervé; Yelin, Ronit et al. (2011) Promotion of avian endothelial cell differentiation by GATA transcription factors. Dev Biol 353:29-37
Whited, Jessica L; Lehoczky, Jessica A; Austin, Christina A et al. (2011) Dynamic expression of two thrombospondins during axolotl limb regeneration. Dev Dyn 240:1249-58
Lehoczky, Jessica A; Robert, Benoit; Tabin, Clifford J (2011) Mouse digit tip regeneration is mediated by fate-restricted progenitor cells. Proc Natl Acad Sci U S A 108:20609-14

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