Figure 2.

The Val-410 and Pro-411 Pair in the C27 Domain Is Critical for UVR8 Signaling.

(A) Quantitative yeast two-hybrid assays were performed in the presence (+) or absence (−) of UV-B. Means and se from three biological replicates are shown. AD, activation domain construct; BD, binding domain construct; EV, empty vector; β-Gal., β-galactosidase; MU, Miller units.

(B) Immunoblot analysis of UVR8 protein levels in wild-type seedlings (Wassilewskija [Ws]), uvr8-7, and four independent uvr8-7/Pro35S:UVR8^VP-AA transgenic lines (UVR8^VP-AA #10, #11, #13, and #21).

(C) and (D) Images of representative individuals (C) and quantification of hypocotyl lengths (D) of 4-d-old seedlings grown under white light with (+) or without (−) supplementary UV-B light. Means and se are shown (n > 20).

(E) Quantitative RT-PCR analysis of HY5 gene activation in 4-d-old seedlings in response to UV-B irradiation for 1 h. Relative expression is shown as +UV-B/−UV-B (i.e., fold change). Means and se of three biological replicates are shown.

(F) The UVR8^VP-AA protein interacts with COP1 in planta. Coimmunoprecipitation of COP1 with UVR8 [using anti-UVR8^(1–15) antibodies] is shown from 7-d-old wild-type (Ws), uvr8-7/Pro35S:UVR8^VP-AA (line 11), uvr8-7/Pro35S:UVR8 (line 3), and uvr8-7 seedlings. Seedlings were irradiated with broad-band UV-B for 15 min (+) or not (−). IB, immunoblotting; IP, immunoprecipitation.