Effects of Yariv phenylglycosides onRosa cell suspensions: Evidence for the involvement of arabinogalactan-proteins in cell proliferation

Abstract

Treatment of ‘Paul's Scarlet rose (Rosa sp.) cell suspensions with β-D-glucosyl Yariv phenylglycoside (β-D-Glc)3, a chromophoric molecule that selectively binds arabinogalactan-proteins (AGPs), caused inhibition of cell growth in a concentration-dependent manner, with complete inhibition of growth occurring at 50 μM (β-D-Glc)3 in the culture medium. Growth was not inhibited by either α-D-galactosyl or β-D-mannosyl Yariv phenylglycosides which do not bind AGPs. Staining of cells with fluorescein diacetate indicated that (β-D-Glc)3 did not affect cell viability. Upon transfer of 50 μM (β-D-Glc)3-treated cells to control conditions, cell growth recovered with a time-course similar to that of control cells. Cell sizes in control and (β-D-Glc)3-treated cultures were similar, indicating that the mechanism of growth inhibition by (β-D-Glc)3 involved suppression of cell division. Two different analyses of (β-D-Glc)3-treated cells both showed that approximately 95% of the bound (β-D-Glc)3 was in the cell wall. Molecules that bound (β-D-Glc)3 were extracted from the cell wall and were identified as AGPs, as judged by their carbohydrate and amino acid compositions.