Fig. 5. Overexpression of GFP-AtMAP70-5 induces right-handed helical growth. (A,B) Three-day-old seedlings grown vertically on a Phytagel plate; A, wild type, B, GFP-AtMAP70-5 overexpressor showing right-twisting root. (C,D) Two-week-old plants; (C) wild type, (D) GFP-AtMAP70-5 overexpressor, illustrating right-twisting petioles. (E,F) Root epidermal cells from plants as in A and B, illustrating right-twisting epidermal files in the overexpressor (F). (G,H) Microtubules in root epidermal cells of the early elongation zone showing shallow left-handed microtubule helices in the overexpressor (H). (I) Semi-quantitative RT-PCR with AtMAP70-5 (70-5)- and APT1-specific primers shows that the twisted phenotype corresponds to high level of AtMAP70-5 expression. (J,K) Root growth under low levels of GFP-AtMAP70-5 expression (J) is straight but with higher expression levels the cell files twist (K). Bars, 1 mm (A-D); 30 µm (E-H); 100 µm (J,K).