Figure 4.

Interaction Domain Mapping of FBN5 with SPS1 and SPS2.

(A) Schematic diagrams of the bait constructs of FBN5-B variants and full FBN5-A fused to the GAL4 DNA binding domain. The numbers represent amino acid positions at the start and stop positions of the constructs. Full-length FBN5 contains chloroplast-targeting sequences and α-helix and β-sheet structures.

(B) Specificity of the FBN5 interaction with either mature SPS1 or mature SPS2 in the Y2H system. Interactions of FBN5 variants with either mature SPS1 or mature SPS2 fused to the GAL4 DNA-activation domain were examined in each yeast transformant (PBN204) on growth-selective medium lacking Leu and Trp (SD-LW) or on selective medium also lacking Ura (SD-LWU) or Ade (SD-LWA). β-Galactosidase activity was tested in each colony on SD-LW medium. Positive control was yeast transformed with the PTB (polypyrimidine tract binding protein) bait plasmid and PTB prey plasmid (+/+). PTB is a homodimeric protein. Negative control was a cell transformed with the parental bait vector (pGBKT7) and prey vector (pGADT7).