Faculty Profile

CIRCADIAN (daily) CONTROL represents a very fundamental yet still very poorly understood feature of higher organisms. Jet lag is a symptom of the disruption of our circadian system. Indeed, most organisms--and even individual unicells and some bacteria--possess a temporal control mechanism over many biochemical and physiological processes. Our research is concerned with the basic molecular and cellular mechanisms responsible for these rhythms in the bioluminescent dinoflagellate Gonyaulax polyedra. Earlier studies included the first demonstration of the phase-dependency of shifting of the clock by light and its action spectrum, as well as the unique ability of inhibitors of protein synthesis to cause such phase-shifts. The circadian rhythm of bioluminescence involves a daily synthesis and destruction of two proteins involved in the biochemical reaction. While the amounts of these proteins increase and decrease by a factor of 10 on a daily basis, the mRNAs for these proteins remain at the same level day and night. Synthesis is thus controlled at the translational level, a feature so far unique to this system. Current studies are focused on the role of protein phosphorylation in the cycle: protein kinase and phosphatae inhibitors cause period changes. Circadian control of gene expression, and the identity of such clock-controlled genes, determined by microarrays, is also under study.

NSF: Bioluminescence: Molecular mechanisms and biochemical control

Harvard Undergraduate course: MCB 186
Circadian Biology: From cellular oscillators to sleep regulation
NAS-Chautauqua short course # 55: Circadian Biology: From Clock Genes and Cellular Rhythms to Sleep Regulation

Rossini C, Taylor W, Fagan T, Hastings JW. Lifetimes of mRNAs for clock-regulated proteins in a dinoflagellate. Chronobiol Int. 2003 Nov;20(6):963-76. PMID: 14680137 [PubMed - indexed for MEDLINE]

Okamoto, OK; Hastings, JW. 2003. Novel dinoflagellate clock-related genes identified through microarray analysis. JOURNAL OF PHYCOLOGY 39 (3): 519-526. [NOT IN PubMed]

Comolli JC, Fagan T, Hastings JW. A type-1 phosphoprotein phosphatase from a dinoflagellate as a possible component of the circadian mechanism.
J Biol Rhythms. 2003 Oct;18(5):367-76. [PMID: 14582853]

Hastings JW. Fifty years of fun.
J Biol Rhythms. 2001 Feb;16(1):5-18. [PMID: 11220778]

Comolli JC, Hastings JW. Novel effects on the Gonyaulax circadian system produced by the protein kinase inhibitor staurosporine.
J Biol Rhythms. 1999 Feb;14(1):11-9. [PMID: 10036988]

Knaust, R; Urbig, T; Li, LM; Taylor, W; Hastings, JW. 1998. The circadian rhythm of bioluminescence in Pyrocystis is not due to differences in the amount of luciferase: A comparative study of three bioluminescent marine dinoflagellates.
JOURNAL OF PHYCOLOGY 34 (1): 167-172. [NOT IN PubMed]

Mittag M, Eckerskorn C, Strupat K, Hastings JW. Differential translational initiation of lbp mRNA is caused by a 5' upstream open reading frame.
FEBS Lett. 1997 Jul 14;411(2-3):245-50. [PMID: 9271214]

Techel D, Chuang E, Lee DH, Comolli J, Hastings JW. Changes in the ultrastructural localization of mRNA for a circadian regulated protein.
Mol Mar Biol Biotechnol. 1996 Dec;5(4):241-8. [PMID: 8983193]

Comolli J, Taylor W, Rehman J, Hastings JW. Inhibitors of serine/threonine phosphoprotein phosphatases alter circadian properties in Gonyaulax polyedra.
Plant Physiol. 1996 May;111(1):285-91. [PMID: 8685268]

Mittag, M; Hastings, JW. 1996. Exploring the signaling pathway of circadian bioluminescence.
PHYSIOLOGIA PLANTARUM 96 (4): 727-732. [NOT IN PubMed]