TY - JOUR ID - 2390 TI - Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures JO - Bot. Acta PY - 1997 SP - 452-457 AU - Hause, B. AU - Feussner, K. AU - Wasternack, C. AU - VL - 110 UR - DO - 10.1111/j.1438-8677.1997.tb00662.x AB - Diadenosine 5′,5′”‐P1,P4‐tetraphosphate (Ap4A) cleaving enzymes are assumed to regulate intracellular levels of Ap4A, a compound known to affect cell proliferation and stress responses. From plants an Ap4A hydrolase was recently purified using tomato cells grown in suspension. It was partially sequenced and a peptide antibody was prepared (Feussner et al., 1996). Using this polyclonal monospecific antibody, an abundant nuclear location of Ap4A hydrolase in 4‐day‐old cells of atomato cell suspension culture is demonstrated here by means of immunocytochemical techniques using FITC (fluorescein‐5‐isothiocyanate) labeled secondary antibodies. The microscopic analysis of the occurrence of Ap4A hydrolase performed for different stages of the cell cycle visualized by parallel DAPI (4,6‐diamidino‐2‐phenylindole) staining revealed that the protein accumulates within nuclei of cells in the interphase, but is absent in the nucleus as well as cytoplasm during all stages of mitosis. This first intracellular localization of an Ap4A degrading enzyme within the nucleus and its pattern of appearance during the cell cycle is discussed in relation to the suggested role of Ap4A in triggering DNA synthesis and cell proliferation. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER -