J. Grandmaison et Rk. Ibrahim, EVIDENCE FOR NUCLEAR-PROTEIN BINDING OF FLAVONOL SULFATE ESTERS IN FLAVERIA-CHLORAEFOLIA, Journal of plant physiology, 147(6), 1996, pp. 653-660
The analysis of isolated nuclei from Flaveria chloraefolia leaves reve
aled the association of flavonol sulfate esters with the nuclear compa
rtment, in addition to their presence in the cytoplasm. The presence o
f flavonol sulfates in the nuclei of Flaveria leaves, has been confirm
ed by immunogold labeling with monospecific polyclonal antibodies, rai
sed against quercetin 3,7,4'-trisulfate. A nuclear protein fraction th
at specifically binds quercetin 3-sulfate (Q3-S) has been partially pu
rified by affinity chromatography on a Q3-S-Sepharose affinity column.
The nuclear protein exhibited a strong affinity for Q3-S with a bindi
ng constant of 85 nmol L(-1). The putative biological significance of
sulfated flavonol nuclear binding is discussed in relation to the well
documented roles of flavonoids and of metabolite sulfation in cellula
r development.