Dr. Daniel C. Weinstein
Ph.D.(The Rockefeller University)
Office: NSB E -124 Tel: 718-997-4552
Laboratory: NSB E-121; 718-997-4258
My laboratory's effort focuses on elucidating the signaling mechanisms underlying germ layer formation and patterning in the vertebrate embryo. Toward this end, we are engaged in two related projects.
1) Regulation of differentiation, self-renewal, and morphogenesis by Ctr1
A recurrent theme in animal development is the prominent role held by a small number of signaling molecules in the initiation of a wide variety of biological outcomes. A dramatic example of this phenomenon occurs during early vertebrate development, when Fibroblast Growth Factor (FGF) signaling mediates multiple embryonic events, including the formation of the mesodermal germ layer, the establishment of the neurectoderm, and the morphogenetic movements that regulate gastrulation.
For a number of years, our group has been involved in the characterization of the signaling cascades underlying mesoderm induction in the frog Xenopus laevis. We have performed protein interaction screens to identify novel mediators of FGF signaling during early vertebrate development, and have identified the Copper Transporter 1 (Ctr1) protein as one of several factors that physically interacts with the Src-related non-receptor tyrosine kinase Laloo, the latter required for FGF-mediated mesoderm induction. We have found that Ctr1 functions as a regulator of multiple events during early vertebrate embryogenesis, including mesoderm formation, neural induction, and tissue morphogenesis, all processes that are regulated by FGF. Our data point to both Copper-dependent and Copper-independent functions for Ctr1, and suggest that the requirement for Ctr1 during development is mediated in part via activation of the Ras/MAP kinase signaling cassette. Our research further suggests a striking conservation of function in higher vertebrates: Ctr1 is required for the differentiation of mouse embryonic stem (ES) cells in culture, as ctr1-/- ES cell lines retain characteristics of pluripotency under conditions that otherwise favor differentiation.
Our studies support a model in which vertebrate Ctr1 functions as a key regulator of the differentiation capacity of both stem and progenitor cell populations. Current efforts in the lab include complementary studies in mammalian ES cells and amphibian embryos to define the signaling events through which Ctr1 regulates progenitor cell fate and morphogenesis, and to determine the requirement for Ctr1 in stem cell differentiation and self-renewal.
Model depicting a role for Ctr1 in the interpretation of FGF-receptor interaction as either a differentiation or a morphogenesis cue during early development of the frog Xenopus laevis (from Haremaki et al., 2007).
2) Suppression of ectopic germ layer formation by forkhead transcription factors
The molecular basis of vertebrate germ layer formation has been the focus of intense scrutiny for decades; only recently, however, have studies demonstrated that the regulated inhibition of ectopic germ layer development is also critical for patterning the early vertebrate embryo. Over the last few years, we have spent considerable effort on the characterization of Xema (Xenopus Ectodermally-expressed Mesendoderm Antagonist), a novel member of the Foxi-subclass of winged helix transcription factors that is involved in the suppression of ectopic mesendoderm in cells of the presumptive ectoderm. Xema transcripts are restricted to the animal pole ectoderm during early Xenopus development, and misexpression of exogenous Xema RNA inhibits mesoderm induction, both by growth factors and in the marginal zone, in vivo. Conversely, Xema knockdown stimulates the expression of a wide range of mesodermal and endodermal marker genes in the animal pole. Our studies demonstrate that Xema is both necessary and sufficient for the inhibition of ectopic mesendoderm in the cells of the presumptive ectoderm. Taken together with studies from our lab and others on the related FoxA2/HNF3b , this body of research supports a model in which Fox proteins are fundamental mediators of the widespread suppression of ectopic germ layer development during early vertebrate embryogenesis. Recent efforts in the laboratory have sought to define the source and nature of the mesendodermalizing signal suppressed by Xema, and to characterize direct targets and effectors of Xema-mediated suppression.
Haremaki, T., Sridharan, J., Dvora, S., and Weinstein, D.C. (2010). Regulation of vertebrate embryogenesis by the Exon Junction Complex core component Eif4a3. Dev. Dyn. 239, 1977-1987.
Haremaki, T., and Weinstein, D.C. (2009). Xmc mediates Xctr1-independent morphogenesis in Xenopus laevis. Dev. Dyn. 238, 2382-2387.
Haremaki, T., Fraser, S.T., Kuo, Y-M., Baron, M.H., and Weinstein, D.C. (2007). Vertebrate Ctr1 coordinates morphogenesis and progenitor cell fate and regulates embryonic stem cell differentiation. Proc. Natl. Acad. Sci. USA. 104, 12029-12034.
Suri, C., Haremaki, T., and Weinstein, D.C. (2005). Xema, a foxi-class gene expressed in the gastrula stage Xenopus ectoderm, is required for the suppression of mesendoderm formation. Development 132, 2733-2742.
Suri, C., Haremaki, T., and Weinstein, D.C. (2004). Inhibition of mesodermal fate by Xenopus HNF3b/FoxA2. Dev. Biol. 265, 90-104.
Hama, J., Suri, C., Haremaki, T., and Weinstein, D.C. (2002). The molecular basis of Src kinase specificity during vertebrate mesoderm formation. J. Biol. Chem. 277, 19806-19810.
Hama, J., Xu, H., Goldfarb, M., and Weinstein, D.C. (2001). SNT-1/FRS2a physically interacts with Laloo and mediates mesoderm induction by Fibroblast Growth Factor. Mech. Dev. 10, 195-204.
Song, Y., Cohler, A.N., and Weinstein, D.C. (2001). Regulation of Laloo by the Xenopus C-terminal Src kinase (Xcsk) during early vertebrate development. Oncogene 20, 5210-5214.
Weinstein, D.C., Marden, J., Carnevali, F., and Hemmati-Brivanlou, A. (1998). FGF-mediated mesoderm induction involves the Src-family kinase Laloo. Nature 394, 904-908.
Weinstein, D.C., Honore, E., and Hemmati-Brivanlou, A. (1997). Epidermal induction and inhibition of neural fate by translation initiation factor 4AIII. Development 124, 4235-4242.
Weinstein, D.C., Ruiz i Altaba, A., Chen, W.S., Hoodless, P., Prezioso, V.R., Jessell, T.M., and Darnell, J.E., Jr. (1994). The winged helix transcription factor HNF-3b is required for notochord development in the mouse embryo. Cell 78, 575-588.
Book Chapters and Reviews
Iyengar, R., Diverse-Pierluissi, M.A., Jenkins, S. L., Chan, A.M., Devi, L.A., Sobie, E.A., Ting, A.T., and Weinstein, D.C. (2008). Integrating content detail and critical reasoning by peer review. Science 319, 1189-1190.
Weinstein, D.C. (2005). Mesodermal differentiation: signal integration during development. Science STKE 2005, tr 23.
Weinstein, D.C. (2004). Function of the winged helix transcription factor HNF3b/FoxA2 during gastrulation. In Stern, C. (ed.), Gastrulation, Cold Spring Harbor Laboratory Press, New York, 563-570.
Weinstein, D.C., and Hemmati-Brivanlou, A. (1999). Neural Induction. Annu. Rev. Cell. Dev. Biol. 15, 411-433.
List of Publications from PubMed