Immunolocalization of O-Methyltransferase and Peroxidase in Differentiating Xylem of Poplar

Anti-O-methyltransferase (OMT) antiserum was prepared using a part of the OMT-histidine fusion protein expressed in transformed E. coli cells as antigens. Anti-peroxidase antiserum was prepared using artificially synthesized peptides. Immunocytochemistry revealed that OMT and peroxidase are localized in differentiating xylem cells of Populus euramericana. OMT labeling was observed in the cytosol and peroxidase labeling was observed in the ER or near the ER membrane.