Circadian regulation of the synthesis of the enzyme GAPDH
is translationally controlled
Fagan, T.1, Morse, D.2, Hastings, J.W.1
1Dept of Molecular & Cellular Biology, Harvard University, 16 Divinity Ave.,
Cambridge, MA 02138, USA
2Dept of Biology, Universite de Montreal, 4101 Sherbrooke E., Montreal, HIX 2B2, Canada
The circadian rhythm of bioluminescence in the dinoflagellate Gonyaulax polyedra correlates with the daily synthesis and destruction of two proteins, luciferase and the luciferin binding protein, both of which are involved in the light emitting reaction. The mechanism, while not fully elucidated, involves translational control of both proteins. Many other processes in Gonyaulax are also circadian regulated (e.g., photosynthesis, cell division and motility), acrophases of which fall at different times of day. Studies of circadian-regulated proteins associated with different processes should give insight concerning the mechanisms involved in the regulation and phase control of different rhythms. Pulse-labeling at two different circadian times 12 hours apart showed that the synthesis of many proteins is circadian-controlled. Marcovic et al. (1996) measured synthesis rates every two hours over the circadian cycle; on 2D gels ten proteins exhibiting rhythmicity fell into three time bins, based on time when maximum synthesis occurred. In the present work, we undertook the study of one such protein, the enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and its gene. The synthesis of GAPDH, which occurs preferentially during late subjective night and early subjective day, also appears not to be due to changes in transcript abundance, but in ist activity.
Markovic, P., Roenneberg, T., Morse, D. (1996) Phased protein synthesis at several circadian times does not change protein levels in Gonyaulax. J. Biol. Rhythms 11: 57-67
| LOCATION |
DATE |
TIME |
| Lecture Hall II |
Thursday, April 9 |
02:00 pm |