Elaine Tobin
email: etobin@ucla.edu
phone: (310) 825-7700
office: 3313A Life Sciences
lab: 3206
homepage: http://www.mcdb.ucla.edu/Research/Tobin/lab.html
Education
B.A.honors, Chemistry, Oberlin College 1966
M.A., Biology,
Stanford University 1967
Ph.D., Biology, Harvard University 1972
Research Interests
A transcription factor named CCA1 (CIRCADIAN CLOCK ASSOCIATED 1) interacts with a phytochrome regulatory region of a photosynthetic gene of Arabidopsis thaliana. CCA1 is of particular interest because it is involved in both phytochrome and circadian regulation. Overexpression of the protein abolishes many different kinds of circadian rhythms including gene expression, leaf movements, photoperiodic flowering, and rhythmic growth of the hypocotyl. It is part of a negative feedback loop that suppresses its own synthesis. In fact, our work has shown that it is almost certainly part of the circadian oscillator itself. Our current work aims to define exactly how it interacts with other proteins and how the functioning of the oscillator is regulated. We have found that phosphorylation of CCA1 by the protein kinase CK2 is one way in which the clock is regulated. Other proteins that can interact with CCA1 are currently being investigated. We are also interested in the molecular basis of the interaction of the phytochrome photoreceptors and circadian rhythms.
Selected Publications
Knowles, S.M., Lu,X.S., Tobin, E.M.. 2008. Testing Time: Can Ethanol-Induced Pulses of Proposed Oscilator Components Phase Shift Rhythms in Arabidopsis? Journal of Biological Rhythms 23: 463-471 .
Thain, S.C., Vandenbussche, F., Laarhoven, L.J.J., Dowson-Day, M.J., Want, Z.Y., Tobin, E.M., Harren, F.J.M., Millar, A.J., and van der Straeten, D. 2004. Circadian rhythims of ethylene emission in Arabidopsis Plant Physiol 136: 3751-3761 .
Green, R.M. and Tobin, E.M.. 2002. The role of CCA1 and LHY in the plant circadian clock Devel. Cell 2: 516-518 .
Green, R.M. Tingay, S., Wang, Z.-Y., and Tobin, E.M.. 2002. Circadian rhythms confer a higher level of fitness to Arabidopsis plants Plant Physiol 129: 576-584 .
Santiago-Ong, M.S., Green, R.M., Tingay, S., Brusslan, J. and Tobin, E.M.. 2001. shygrl1 is a mutant affected in multiple aspects of photomorphogenesis Plant Physiol 126: 587-600 .
Barak, S., Tobin, E.M., Andronis, C., Sugano, S. and Green, R.M.. 2000. All in good time: the Arabidopsis ciradian clock Trends Plant Sci 5: 517-522 .
Green, R., and Tobin, E.M.. 1999. Loss of the circadian clock associated 1 (CCA1) protein causes altered clock-regulated gene expression Proc. Natl. Acad. Sci 96: 4176-4179 .
Sugano, S., Andronis, C., Ong, M.S., Green, R.M., and Tobin, E.M.. 1999. The protein kinase CK2 is involved in regulation of circadian rhythms in Arabidopsis Proc. Natl. Acad. Sci.USA 96: 12362-12366 .
Wang, Z-Y. and Tobin, E.M.. 1998. Constitutive expression of the CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) gene disrupts circadian rhythms and supresses its own expression Cell 93: 1207-1217 .
Sugano S., Andronis, C., Green, R.M., Wang, Z.-Y. and Tobin E.M.. 1998. Protein kinase CK2 interacts with and phosphorylates the Arabidopsis CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) protein Proc. Natl. Acad, Sci. USA 95: 11020-11025 .