Rob E. Steele
Molecular biology of Hydra development
The goal of the research in our lab is to understand the molecular circuitry underlying development in the simple animal Hydra. We have identified a number of genes whose protein products are candidates for regulating the specification of cell identities and the formation of the axial pattern of the adult Hydra polyp. One group of genes we are examining encodes homeodomain-containing transcription factors. Examination of the expression patterns of these genes in normal and experimentally manipulated Hydra indicates that these genes play important roles in regulating the formation of the head and the foot of the polyp. The other genes we are concentrating on encode receptor protein-tyrosine kinases. We have identified a number of Hydra genes encoding such receptors, including one which encodes a homologue of the vertebrate insulin receptor. The expression pattern of the gene encoding the insulin receptor homologue suggests that this receptor plays a role in controlling both cell division and differentiation of the tentacles and the foot of the polyp. In addition we have identified a novel class of receptor protein-tyrosine kinase in Hydra which appears to use carbohydrates as ligands. Genes encoding members of this class of receptor protein-tyrosine kinase are unusually abundant in Hydra. We are investigating the possibility that receptors of this class play a role in self/non-self recognition in Hydra. From our studies of the molecular biology of development in a simple animal such as Hydra we expect to gain insight into how the mechanisms which regulate development in more complex animals evolved.
Unger, T.F., and R.E. Steele (1992). Biochemical and cytological changes associated with expression of deregulated pp60src in Xenopus oocytes. Mol. Cell. Biol. 12: 5485- 5498.
Shenk, M.A., and R.E. Steele (1993). A molecular snapshot of the metazoan 'Eve.' Trends Biochem. Sci. 18: 459-463.
Shenk, M.A., H.R. Bode, and R.E. Steele (1993). Expression of Cnox-2, a HOM/HOX gene in hydra, is correlated with axial pattern formation. Development 117: 657-667.
Chan, T.A., C.A. Chu, K.A. Rauen, M. Kroiher, S.M. Tatarewicz, and R.E. Steele (1994). Identification of a gene encoding a novel protein-tyrosine kinase containing SH2 domains and ankyrin-like repeats. Oncogene 9: 1253-1259.
Steele, R.E., P. Lieu, N.H. Mai, M.A. Shenk, and M.P. Sarras, Jr. (1996). Response to insulin and the expression pattern of a gene encoding an insulin receptor homologue suggest a role for an insulin-like molecule in regulating growth and patterning in hydra. Dev. Genes Evol. 206: 247-259.
Martinez, D.E., M.-L. Dirksen, P.M. Bode, M. Jamrich, R.E. Steele, and H.R. Bode (1997) Budhead, a Fork Head/HNF-3 Homologue, is expressed during axis formation and head specification in hydra. Dev. Biol. 192: 523-536.
Hassel, M., D.M. Bridge, N.A. Stover, H. Kleinholz and R.E. Steele (1998). The level of expression of a protein kinase C gene may be an important componenbt of the patterning process in Hydra. Dev. Genes. Evol. 207: 502-514.