To see interviews with Elena Casey and previous undergraduate research go to Georgetown College News
The embryos of the African clawed frog, Xenopus laevis, have the been a favorite tool of classical embryologists for over 100 years. Xenopus has been useful in the study of vertebrate development because the embryos are large, easily manipulated and develop externally, allowing analysis at very early, 
highly conserved stages of development. Therefore, embryos can be subjected to microsurgical manipulation to remove or transplant embryonic tissues, or injected to express large quantities of a transcription factor. Such experiments have provided information on the inductive contacts required for pattern formation and have defined many of the molecular interactions involved in early development.
The goal of the Casey lab is to define the gene network that controls the induction and patterning of the central nervous system. The CNS is derived from the ectoderm which can develop into either epidermal or neural tissue (see below). The neural tissue can then differentiate into either neurons or glial cells. Many of the signal pathways and trasncription facors involved in directing these fate choices are known however, the exact molecular mechanism is unknown. To elucidate this mechanism, our studies focus on the regulation of the SoxB genes which encode highly conserved, HMG box transcription factors involved in the formation of CNS. By studying the regulation of the SoxB genes and the function of proteins, we can piece together the steps that drive ectoderm to develop into epidermis and neural tissue to form a neuron.
Presently we are interested in studying neural induction and specification in both Xenopus and the sea squirt Ciona intestinalis. By using both organisms, we can investigate the evolutionary conservation of the regulation and function of the Sox proteins.
The aspects of this project in which we are currently focused on are:
1. Identification of genes and regulatory regions involved in early neural induction in the sea squirt (Ciona intestin
alis).
2. Defining the Regulation and fucntion of SoxB genes which encode transcription factors involved in neural stem cell maintenance, competence and
differentiation
in Xenopus laevis.
3. Comparison of the regulatory mechanisms
of these neural genes in urochordates (C. intestinalis) , hemichordates (Saccoglossus kowalsevskii) and anurans (X.
laevis).
Relevant Publications
Blackiston D, Silva Casey E, and M Weiss. 2008. Retention of Memory through Metamorphosis: Can a Moth Remember what it Learned as a Caterpillar? PLoS ONE, 3 (3), e1736. Read Blog on article. Discovery, Live Science
Cunningham DD, Meng J, Fritszch B, and EM Silva Casey. Cloning and developmental expression of the soxB2 genes, sox14 and sox21, during Xenopus laevis embryogenesis. IJDB, in press.
Rogers C , Archer T , Cunningham DD, Grammer TC and EM Silva Casey. 2008. Sox2 and Sox3 expression during Xenopus neurogenesis are controlled by distinct regulatory mechanisms. Developmental Biology, Volume 313, Issue 1, Pages 307-319
Brunelli, S., Casey, E.S., Bell, D., Harland, R., and R. Lovell-Badge. 2003. Expression of SOX3 throughout the developing central nervous system is dependent on the combined action of discrete, evolutionarily conserved regulatory elements. Genesis 36: 12-24.
Di Gregorio, A., Harland R., Levine, M. and E.S. Casey. 2002. Tail morphogenesis in the ascidian Ciona intestinalis
requir
es cooperationbetween notochord and muscle. Developmental Biology, Volume 244, Issue 2, Pages 385-395. [pdf]
Conlon, F., Fairclough, L., Price, B., Casey E.S. and J.C. Smith. 2001. Determination of T-Box protein specificity. Development 128:3749-3758.
Rodriguez, T., Casey, E.S., Harland, R.M., Smith, J.C., and R. Beddington. 2001. Distant Enhancer elements control Hex expression during gastrulation and organogenesis. Developmental Biology 234: 304-316.
Casey, E.S., Fairclough, L., Tada, M.,Wylie, C., Heasman, J., and J.C. Smith. 1999. Bix4 is activated directly by VegT and mediates endoderm formation in Xenopus development. Development 126: 4193-4200.
Casey E.S., Reilly, M., Conlon, F., and J.C. Smith. 1998. The T-Box transcription factor Brachyury activates expression of eFGF by binding to a non-palindromic response element. Development 125: 3887-3894.
Tada, M., Casey, E.S., Fairclough, L., and J.C. Smith. 1998. Bix1, a direct target of Xenopus T-box genes, causes formation of ventral mesoderm and endoderm. Development 125: 3997-4006.