Fig. 5. Affinity purification of p34 on amino-purvanol-sepharose beads. The effect of amino-purvalanol was tested in vitro on the histone H1 kinase activity of extracts from cells arrested at the G1/S transition by a treatment with 100 µM olomoucine from 3 to 36 hours AF (black in A), or in mitosis by a treatment with 0.33 µM nocodazole from 3 to 36 hours AF (white in A). Methyl-amino-purvalanol (30 µM) was used as a control. (B) Although two PSTAIRE CDK-like proteins, p32 and p34, were bound to p9^CKShs1 (p9^CKShs1) in extracts from 48-hour-old embryos, only one (p34) was retained on amino-purvalanol-sepharose beads (APV), as detected with the anti-PSTAIRE antibody. Note that p34 could not be completely depleted from cells extracts using amino-purvalanol beads, as the supernatant still contained significant amounts of p34 that could be subsequently fixed on p9^CKShs1 beads (Sup APV/p9^CKShs1). Throughout the first cell cycle, from 2 to 10 hours AF, only the p34 PSTAIRE CDK-like protein was retained on amino-purvalanol beads but not on methyl-amino-purvalanol beads, as detected with the anti-PSTAIRE antibody. The data shown are representative of the results of three independent experiments.

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