Figure 1.

CRY1 undergoes blue-light-dependent interactions with SPA1. (A) β-Galactosidase assays showing the CRY1–SPA1 interaction in yeast cells treated with blue light (B40, 40 μmol m⁻² sec⁻¹), red light (R40, 40 μmol m⁻² sec⁻¹), or darkness (D). (B) β-Galactosidase assays showing the CRY1–-SPA1 interaction in response to 5 μmol m⁻² sec⁻¹ (B5), 25 μmol m⁻² sec⁻¹ (B25), or 50 μmol m⁻² sec⁻¹ (B50) of blue light for the durations indicated. (C) Colocalization of CRY1 and SPA1 in the nucleus of Arabidopsis cells. Nuclei were isolated from transgenic plants expressing MycSPA1. Samples were probed with anti-CRY1 (rabbit polyclonal IgG), anti-Myc (mouse monoclonal IgG), or preimmune serum (Preim), followed by Rhodaine red-X-conjugated goat-against-rabbit IgG (red) and Diaminotriazinylaminofluorescein-conjugated goat-against-mouse IgG (green). The images of the same cell from separate color channels were merged by the merge program of Photoshop and are shown (Merge). Bar, 5 μm.