Our lab is interested in the roles of the Notch signaling pathway during mouse embryonic development. One area of focus is on the roles of fringe genes in Notch pathway modulation. The fringe genes encode glycosyltransferases that modify Notch and its ligands. Mice have three fringe genes: Lunatic fringe (Lfng), Manic fringe (Mfng) and Radical fringe (Rfng).
Lunatic fringe is a critical gene during vertebrate segmentation. The vertebrate body axis consists of serially repeated elements, the most evident of which are the vertebrae of the skeleton. Somites, which are the precursors of the axial skeleton, therefore provide one of the most obvious examples of segmentation in developing vertebrate embryos. The Notch pathway in general, and Lunatic fringe specifically are required for proper regulation of somitogenesis.
It was proposed over 20 years ago that somitogenesis would be regulated by a cellular clock. Recently many gene expression patterns have been linked to this clock, the mRNA levels of these "clock" genes oscillate with a periodicity that matches the timing of somite formation, supporting the existence of a segmentation clock that regulates somitogenesis. Lfng is one of these cyclic genes, providing a direct link between the segmentation clock and Notch signaling. Using mouse genetics techniques, we identified minimal regulatory elements sufficient to drive cyclic expression of Lfng, and identified specific binding sites required for this regulation. By mutating this critical sequence in the endogenous Lfng locus, we recently found that oscillatory Lfng expression is critical only for development of the anterior skeleton, but is dispensable during tail formation. Interestingly, we find that a second, separable Lfng function during somite patterning is critical for tail development. We are actively pursuing the mechanisms by which Notch signaling plays distinct roles during primary body formation (development of the thoracic and lumbar skeleton) and secondary body formation (development of the sacral and tail vertebrae).
During the course of our research, it became clear that post-transcriptional regulation of Lfng was critical for clock function. We are now utilizing mouse and chicken models to understand the mechanisms controlling both LFNG protein turnover and regulation at the mRNA level. Recent work in the lab implicates microRNAs in segmentation clock function, opening new areas of research.
In other projects we are using genetic manipulation and breeding to create mice that are deficient for two or all three fringe genes to uncover roles for fringe genes that may be hidden by genetic redundancy, and are assessing the importance of Notch signaling during cardiac development with collaborators at Nationwide Children's Research Institute.
Williams D.R., Shifley E.T., Braunreiter K.M., and S.E. Cole (2016). Disruption of somitogenesis by a novel dominant allele of Lfng suggests important roles for protein processing and secretion.. Development 43:822-30
Wahi K., Bochter M.S., and Cole SE. (2016) The many roles of Notch signaling during vertebrate somitogenesis. Semin Cell Dev Biol. 49:68-75.
D'Amato G, Luxán G, Del Monte-Nieto G, Martínez-Poveda B, Torroja C, Walter W, Bochter MS, Benedito R, Cole S, Martinez F, Hadjantonakis AK, Uemura A, Jiménez-Borreguero LJ, de la Pompa JL. (2016). Sequential Notch activation regulates ventricular chamber development. Nat Cell Biol. 18:7-20.
Nandhu M.S., Hu, B., Cole, S.E., Erdreich-Epstein, A., Rodriguez-Gil, D.J., and M. S. Viapiano. (2014) Novel paracrine modulation of Notch-DLL4 signaling by fibulin-3 promotes angiogenesis in high-grade gliomas. Cancer Res. 74:5435-48
Williams, D.R., Shifley, E.T., Lather, J.D. and S.E. Cole. (2014) Caudal skeletal development and the segmentation clock period are sensitive to Lfng dosage during somitogenesis. Dev. Biol. 388:159-69
Miller, A.J and S.E. Cole. (2014) Multiple Dlk1 splice variants are expressed during early mouse embryogenesis. Int. J. Dev. Biol. 58:65-70
Riley, M.F., M.S. Bochter, K. Wahi, G.J. Nuovo and S.E. Cole. (2013) mir-125a-5p-mediated Regulation of Lfng is Essential for the Avian Segmentation Clock. Dev. Cell. 24:554-561
Hu, B., P. Agudelo-Garcia, H. Sim, J. Saldivar, C. Dolan, M. Mora, G. Nuovo, S. E. Cole, and M. Viapiano. (2012) Fibulin-3 promotes glioma growth and resistance through a novel paracrine regulation of Notch signaling. Cancer Res 72:3873-85.
Riley, M.F., K.L. McBride and S.E. Cole. (2011) NOTCH1 missense alleles associated with left ventricular outflow tract defects exhibit impaired receptor processing and defective EMT. BBA Mol. Mech. Dis. 1812:121-9.
Moran, J.L., E.T. Shifley, J.M. Levorse, S. Mani, K.Ostmann, Ariadna Perez-Balaguer, D.M. Walker, T.F. Vogt, and S.E. Cole. (2009) Manic fringe is not required for embryonic development, and fringe family members do not exhibit redundant functions in the axial skeleton, limb, or hindbrain. Dev. Dyn. 238:1803-12.
Shifley, E.T. and S.E. Cole. (2008) Lunatic fringe protein processing by proprotein convertases may contribute to the short protein half-life in the segmentation clock. Biochim Biophys Acta, Mol Cell Res. 1783, 2384-90.
McBride, K.L., M.F. Riley, G.A. Zender, S.M. Fitzgerald-Butt, J.A. Towbin, J.W. Belmont and S.E. Cole. (2008) Notch1 mutations in individuals with left ventricular outflow tract malformations reduce ligand-induced signaling. Hum Mol. Gen. 17, 2886-93.
Ryan, M.J., C. Bales, A. Nelson, D.M. Gonzalez, L. Underkoffler, M. Segalov, J. Wilson-Rawls, S. E. Cole, J.L. Moran, P. Russo, N.B. Spinner, K. Kusumi, and K.M. Loomes. (2008) Bile Duct Proliferation in Jag1/Fringe Heterozygous Mice Identifies Candidate Modifiers of the Alagille Syndrome Hepatic Phenotype. Hepatology 48, 1989-1997.
Shifley, E.T., VanHorn, K.M., Perez-Balaguer, A., Franklin, J.D., Weinstein, M. and S.E. Cole. (2008) Oscillatory Lunatic fringe activity is critical for segmentation of the anterior but not posterior skeleton. Development 135: 899-908
Shifley, E.T. and S.E. Cole. (2007) The vertebrate segmentation clock and its role in skeletal birth defects. Birth Defects Res C Embryo Today. 81:121-133.
Cole, S.E., J.M. Levorse, S.M. Tilghman, and T.F. Vogt. (2002). Clock regulatory elements control cyclic expression of Lunatic fringe during somitogenesis. Dev Cell 3: 75-84.
Cole, S.E., M.S. Mao, S.H. Johnston, and T.F. Vogt. (2001) Identification, expression analysis and mapping of B3galt6, a putative galactosyltransferase with similarity to Drosophila brainiac. Mammalian Genome 12:177-179.
Bohne, J., S.E. Cole, C. Sune, B.R. Lindman, V.D. Ko, T.F. Vogt, and M.A. Garcia-Blanco. (2000) Expression analysis and mapping of the mouse and human transcriptional regulator CA150. Mammalian Genome 11:930-933.