The goal of this research is to elucidate the evolutionary dynamics and structural basis for the evolution of novel functions in a biomedically important gene family, the steroid hormone receptors. We will combine experimental evolution, crystallography, ancestral gene resurrection, and manipulative assays of gene function to analyze how receptors evolve tight molecular partnerships with novel hormonal ligands.
The specific aims are: ? ? 1. Use an experimental evolution system in engineered yeast to select for human estrogen receptors which, like those in some mammary tumors, evolve to be stimulated by taxmoxifen, a major breast cancer drug. Using a battery of functional assays and evolutionary techniques for reconstructing the evolution of receptor sequences, we will determine the mechanistic basis for the evolution of this new ER-ligand interaction and the dynamics of receptor-ligand coevolution. ? ? 2. We will resurrect ancestral steroid receptors (using phylogenetic analysis and gene synthesis) and then evolve these receptors in this same experimental evolution system. Ancestral receptors will be selected to recapitulate the functional shifts in ligand specificity that occurred during real historical evolution over hundreds of millions of years. The mechanistic basis and evolutionary dynamics of this process will be studied in detail. ? ? 3. We will express, crystallize, and determine the three-dimensional structures of ancestral receptors, as well as those of several functionally divergent extant steroid receptors. These structures - together with the data on the evolution of new functions from Aims 1 and 2 - will provide a rich database from which to reconstruct the evolution of receptor protein structures. This is expected to reveal the structural mechanisms by which new receptor functions evolve, both in our experimental evolution system and in real historical evolution. ? ? This synthesis of manipulative, hypothesis-testing techniques will provide unprecedented detailed knowledge of the dynamics and mechanisms by which gene function evolves. These data should help resolve long-standing fundamental issues in evolutionary biology, and also improve our understanding of the structure-function relationships that determine steroid receptor function. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM081592-02
Application #
7476575
Study Section
Genetic Variation and Evolution Study Section (GVE)
Program Officer
Eckstrand, Irene A
Project Start
2007-08-01
Project End
2011-07-31
Budget Start
2008-08-01
Budget End
2009-07-31
Support Year
2
Fiscal Year
2008
Total Cost
$271,397
Indirect Cost
Name
University of Oregon
Department
Type
Organized Research Units
DUNS #
948117312
City
Eugene
State
OR
Country
United States
Zip Code
97403
Katsu, Yoshinao; Cziko, Paul A; Chandsawangbhuwana, Charlie et al. (2016) A second estrogen receptor from Japanese lamprey (Lethenteron japonicum) does not have activities for estrogen binding and transcription. Gen Comp Endocrinol 236:105-114
Harms, Michael J; Thornton, Joseph W (2014) Historical contingency and its biophysical basis in glucocorticoid receptor evolution. Nature 512:203-7
Bridgham, Jamie T; Keay, June; Ortlund, Eric A et al. (2014) Vestigialization of an allosteric switch: genetic and structural mechanisms for the evolution of constitutive activity in a steroid hormone receptor. PLoS Genet 10:e1004058
Colucci, Jennifer K; Ortlund, Eric A (2013) X-ray crystal structure of the ancestral 3-ketosteroid receptor-progesterone-mifepristone complex shows mifepristone bound at the coactivator binding interface. PLoS One 8:e80761
Colucci, Jennifer K; Ortlund, Eric A (2013) Expression, purification and crystallization of the ancestral androgen receptor-DHT complex. Acta Crystallogr Sect F Struct Biol Cryst Commun 69:994-6
Harms, Michael J; Eick, Geeta N; Goswami, Devrishi et al. (2013) Biophysical mechanisms for large-effect mutations in the evolution of steroid hormone receptors. Proc Natl Acad Sci U S A 110:11475-80
Harms, Michael J; Thornton, Joseph W (2013) Evolutionary biochemistry: revealing the historical and physical causes of protein properties. Nat Rev Genet 14:559-71
Eick, Geeta N; Colucci, Jennifer K; Harms, Michael J et al. (2012) Evolution of minimal specificity and promiscuity in steroid hormone receptors. PLoS Genet 8:e1003072
Finnigan, Gregory C; Hanson-Smith, Victor; Stevens, Tom H et al. (2012) Evolution of increased complexity in a molecular machine. Nature 481:360-4
Eick, Geeta N; Thornton, Joseph W (2011) Evolution of steroid receptors from an estrogen-sensitive ancestral receptor. Mol Cell Endocrinol 334:31-8

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