My group members are studying the molecular
mechanisms by which photosynthetic organisms cope with environmental stress
that causes inhibition to photosynthesis and reduction in crop yield.
Understanding these mechanisms will help in developing crop plants that are
able to thrive even under harsh environmental conditions. Currently we are
focusing our studies on a family of four high light inducible polypeptides
(HLIP) with similarity to the light harvesting chlorophyll a/b-binding proteins of vascular
plants in the cyanobacterium Synechocystis
sp. PCC 6803. These polypeptides accumulate under a variety of stress
conditions and they are required for surviving exposure to high intensity
light. The exact mechanism of HLIP action and the function of these
polypeptides in survival during high light exposure are not clearly
understood. HLIPs are preserved in vascular plants; they may play important
roles in these systems as well. The regulatory mechanism that governs the
expression of the genes encoding HLIPs (hli)
has not yet been elucidated. Several important questions are being
addressed. These include how hli
genes are regulated, whether HLIPs form complexes, and what are the roles
of HLIPs in cell survival. The approaches being used combine genomics,
proteomics and bioinformatics tools.
Jantaro, S., Lu, B., Majeed, W., Bailey, M. & He, Q. (2008) The high
light inducible polypeptides (HLIP) stabilize trimeric photosystem I in
high light in Synechocystis PCC
6803. Plant Physiol. 147,
Jantaro, S., Ali, Q., Lone,
S. & He, Q. (2006) Suppression of the lethality of high intensity light
to a mutant lacking four hli
genes by the inactivation of the regulatory protein PfsR in Synechocystis PCC 6803. J. Biol. Chem. 281, 30865-30874.
Hsiao, H-Y., He, Q., van
Waasbergen, L. G. & Grossman, A. R. (2003) Control of photosynthetic
and high light-responsive genes by the histidine kinase DspA: Negative and
positive regulation and interactions between signal transduction pathways. J. Bacteriol. 186, 3882-3888.
Havaux, M., Guedeney, G., He,
Q. & Grossman A. (2003) Elimination of high-light-inducible polypeptides
related to eukaryotic chlorophyll a/b-binding
proteins results in aberrant photoacclimation in Synechocystis PCC 6803. Biochim.
Biophys. Acta. 1557, 21-33.
He, Q. (2003) Microalgae as
platforms for recombinant proteins. Handbook
of Microalgal Cuture, Ed by A. Richmond. pp471-484, Blackwell Science.
Grossman, A. R. Bhaya, D.
& He, Q. (2001) Tracking the light environment by cyanobacteria and the
dynamic nature of light harvesting. J.
Biol. Chem. 276, 11449-11452.
He, Q., Dolganov, N., Bjorkman,
O. & Grossman, A. R. (2001) The high light inducible polypeptides in Synechocystis PCC 6803: Expression
and function in high light. J. Biol.
Chem. 276, 306-314.
He, Q., Paulsen, H. &
Vermaas, W. (1999) Expression of a higher plant light-harvesting chlorophyll
a/b-binding protein in Synechocystis
sp. PCC 6803. Eur. J. Biochem.
He, Q. & Vermaas, W.
(1999) Genetic deletion of proteins resembling type IV-pilins in Synechocystis
sp. PCC 6803: Their role in binding or transfer of newly synthesized
chlorophyll. Plant Mol. Biol. 39,
He, Q. & Vermaas, W.
(1998) Chlorophyll a availability
affects psbA translation and D1
precursor processing in vivo in Synechocystis sp. PCC 6803. Proc. Natl. Acad. Sci. USA 95,
He, Q., Brune, D., Nieman, R.
& Vermaas, W. (1998) Chlorophyll a
synthesis upon interruption and deletion of por coding for the light-dependent NADPH:protochlorophyllide oxidoreductase in a photosystem
I-less/chlL- strain of
Synechocystis PCC 6803. Eur. J. Biochem. 253, 161-172.