Abstract
Cell-to-cell communication with molecules secreted from cells may play crucial roles in coordinating neighbor cells to form xylem. To investigate secreted molecules involved in xylem differentiation, we made monoclonal antibodies against a conditioned medium prepared from cultured Zinnia mesophyll cells differentiating into tracheary elements (TEs) using a phage display antibody method. A phage antibody library (5.1 X 10 7 cfu) was constructed from spleen mRNA of immunized mouse. To screen TE-differentiation specific phage antibodies, subtraction method was performed with a conditioned medium prepared from a non-differentiating culture. Clones with highly expressed antibody were selected with a colonylift immunoassay. Immunohistochemical analyses were performed for 93 clones with Zinnia plants. All of them were localized in apoplast and showed different localization patterns including the vascular cell-specific pattern, indicating that this strategy allows us to isolate systematically antibodies against candidates of secreted factors involved in vascular differentiation.
