Elaine Tobin
Phone: (310) 825-7700
Office: 3313A Life Sciences
Lab: 3206 Life Sciences


B.A.Honors, Oberlin College, Chemistry 1966
M.A., Stanford University, Biology 1967
Ph.D., Harvard University, Biology 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

Lu, S.X. and Tobin, E.M., "Chromatin remodeling and the circadian clock: Jumonji C-domain containing proteins", Plant Sig. Behav 6: 810-814 (2011).

Bu, Q., Zhu, L., Dennis, M.D., Yu, L., Lu, S.X., Person, M.D., Tobin, E.M., Browning, K. and Huq, E., "Phosphorylation by CK2 enhances the rapid light-induced degradation of PHYTOCHROME INTERACTING FACTOR 1 in Arabidopsis", J. Biol. Chem 286: 12066-12074 (2011).

Lu, S.X., Knowles, S.M., Webb, C.J., Celaya, B.R. and Tobin, E.M., "The JmjC domain-containing protein JMJ30 regulates period length in the Arabidopsis circadian clock", Plant Physiol 155: 906-915 (2011).

Baudry, A., Ito, S., Song, .H., Strait, A.A., Kiba, T., Lu, S., Henriques, R., Pruneda-Paz, J.L., Chua, N.-H., Tobin, E.M., Kay, S.A. and Imaizumi, T., "F-box proteins FKF1 and LKP2 act in concert with ZEITLUPE to control Arabidopsis clock progression", Plant Cell 22: 606-622 (2010).

Gardner, G., Lin, C., Tobin, E.M., Loehrer, H. and Brinkman, D., "Photobiological properties of the inhibition of etiolated Arabidopsis seedling growth by ultraviolet-B irradiation", Plant Cell Environ 32: 1573-1583 (2009).

Lu, S.X., Knowles, S.M., Andronis, C., Ong, M.S. and Tobin, E.M., "CIRCADIAN CLOCK ASSOCIATED and LATE ELONGATED HYPOCOTYL function synergistically in the circadian clock of Arabidopsis", Plant Physiol 150: 834-843 (2009).

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, "Circadian rhythims of ethylene emission in Arabidopsis", Plant Physiol 136: 3751-3761 (2004).

Green, R.M. Tingay, S., Wang, Z.-Y., and Tobin, E.M., "Circadian rhythms confer a higher level of fitness to Arabidopsis plants", Plant Physiol 129: 576-584 (2002).

Green, R.M. and Tobin, E.M., "The role of CCA1 and LHY in the plant circadian clock", Devel. Cell 2: 516-518 (2002).

Santiago-Ong, M.S., Green, R.M., Tingay, S., Brusslan, J. and Tobin, E.M., "shygrl1 is a mutant affected in multiple aspects of photomorphogenesis", Plant Physiol 126: 587-600 (2001).

Barak, S., Tobin, E.M., Andronis, C., Sugano, S. and Green, R.M., "All in good time: the Arabidopsis ciradian clock", Trends Plant Sci 5: 517-522 (2000).

Sugano, S., Andronis, C., Ong, M.S., Green, R.M., and Tobin, E.M., "The protein kinase CK2 is involved in regulation of circadian rhythms in Arabidopsis", Proc. Natl. Acad. Sci.USA 96: 12362-12366 (1999).

Green, R., and Tobin, E.M., "Loss of the circadian clock associated 1 (CCA1) protein causes altered clock-regulated gene expression", Proc. Natl. Acad. Sci 96: 4176-4179 (1999).

Sugano S., Andronis, C., Green, R.M., Wang, Z.-Y. and Tobin E.M., "Protein kinase CK2 interacts with and phosphorylates the Arabidopsis CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) protein", Proc. Natl. Acad, Sci. USA 95: 11020-11025 (1998).

Wang, Z-Y. and Tobin, E.M., "Constitutive expression of the CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) gene disrupts circadian rhythms and supresses its own expression", Cell 93: 1207-1217 (1998).