Fig. 5. Identification of a signal domain that is necessary and sufficient for inter- and/or intracellular movement of the protein. (A) Diagram of the deletion mutants of CPC. The N-terminal domain is shown in red, the Myb domain in blue. (B-D) CLSM images showing GFP fluorescence (green) and PI fluorescence (red) in the root epidermis of 5-day-old seedlings. (B) Like full-length CPC fused to GFP, 1-79G moved from hairless cells to root hair cells (file of hair cells is indicated by an asterisk) and accumulated in the nuclei of both cell types. (C) In contrast to 1-79G, 1-75G remained distributed throughout the cytoplasm of the hairless cells. (D) A partial defect in CPC movement in 10-83G was indicated by the occurrence of the GFP signal only in a fraction of hair cells, with 1-79G and 10-83G accumulated in nuclei. (E) Diagrammatic representation of a signal domain (residues 1 to 79, as indicated by the yellow and green bar) that is necessary and sufficient for CPC cell-to-cell movement. The domain, amino acid residues 1 to 79, contains the N terminus and a part of the Myb domain. The regions whose deletions conferred defects in the intercellular movement of CPC:GFP were tentatively designated S1 and S2 (as indicated by the yellow bars). As the behavior of 1-75G shows (C), S2 also is required for the nuclear accumulation of CPC. Scale bar: 50 µm.