Immunocytochemical localization of proteins in differentiating tissues of Pisum sativum.

Although there may be documented morphological changes during development, it is obvious that important changes in protein content occur in a vascular plant during the several stages of differentiation. In the absence of the latter information, an approach has been established for the localization of antigenic proteins in developing tissues of Pisum sativum. Monoclonal antibodies were raised to proteins extracted from pea internode tissue, and employed for the localization of three proteins in tissue sections. One of the proteins has two polypeptide subunits with molecular weights of 25,000 and 40,000 daltons, and the antibody binds to both of them. The three monoclonal antibodies produce different patterns of cellular localization in the tissue sections, as visualized by indirect immunocytochemical labeling. In another series of analyses, quantitative and qualitative differences in the protein contents of apical shoot tissue and mature internode shoot tissue have been found. These studies were based on the use of Western blots with both polyclonal (rabbit) antibodies and monoclonal (mouse) antibodies.