Figure 1.

Analysis of protein interactions between deleted versions of ROXY1 and two TGA proteins. A, Schematic representation of deleted forms of ROXY1 proteins. In ROXY1Δ1 to ROXY1Δ8, the C-terminal one to eight amino acids were deleted, respectively; ROXY1C14 comprises the ROXY1 C-terminal 14 amino acids alone. Amino acids comprising the α5 helix and the C terminus are indicated by solid and dashed lines, respectively. B, Quantitative β-galactosidase activity assays measuring the interaction of the ROXY1 C-terminal deletion mutants and the ROXY1 C-terminal 14 amino acids with two TGA proteins. ROXY1Δ1 to ROXY1Δ8, ROXY1C14, as well as wild-type ROXY1 were used as bait and expressed as a fusion to the GAL4-BD, whereas PAN and TGA3 were used as prey and expressed as fusion proteins to the GAL4-AD. Black and gray bars indicate PAN-AD and TGA3-AD, respectively; white bars represent controls. Data are means ± sd of three independent experiments. C, Western-blot analysis of protein extracts from yeast cells expressing ROXY1Δ7 and ROXY1Δ8 fused to the GAL4-BD. ROXY1 and its two truncated forms fused to GAL4-BD have a molecular mass of about 33 to 34 kD (14 kD for ROXY1, 13 kD for ROXY1Δ7 and ROXY1Δ8, and 20 kD for GAL4-BD). Molecular mass markers (kD) are indicated at right. [See online article for color version of this figure.]