Fig. 2. Effects of CDK inhibitors on early morphogenesis of Fucus zygotes. Treatments from 2 hours AF with either 100 µM olomoucine (A,E), 30 µM roscovitine (B,F) or 5 µM amino-purvalanol (C,G) prevent nuclear division, as revealed by staining DNA with mithramycin A (A-C), as well as the polar localisation of cell wall sulphated compounds, as detected by staining isolated walls with TBO (E-G). Arrowheads in A-C point to the decondensed nuclei. (D) Control embryo treated from 2 to 24 hours AF with 400 µM isoolomoucine. (H) Cell wall of 12-hour-old control zygotes exhibiting sulphated compounds localised at the future rhizoid pole. (I,J) Zygotes treated from 2 hours AF with either 20 µM aphidicolin or with lower doses of olomoucine (35 µM) germinated and elongated a rhizoid as observed at 36 hours AF. Note the presence of dispersed chromosomes after treatment with 35 µM olomoucine (arrow in J). (K) Two-week-old embryo recovering from a 28 hour-incubation with 100 µM olomoucine from 2 hours AF. Note that the multicellular embryo is is devoid of any rhizoids. By contrast, an apical hair (ah) is present. Scale bar: 25 µm in A-C; 30 µm in E-H; 40 µm in D,J; 50 µm in I; 80 µm in K.
