Immunostaining and interphase arrangement of field bean kinetochores

More than 100 sera from patients with scleroderma CREST (calcinosis, Raynaud phenomenon, esophageal dismotility, sclerodactyly, telangiectasia) were tested in order to detect antigenic nuclear components of the field bean Vicia faba (2n = 12). Kinetochores of mitotic chromosomes and prekinetochores of interphase cells from root-tip meristems were specifically labelled via an indirect immunofluorescence procedure by antibodies of one of these sera. In 44% of interphase nuclei in which centromeres could be identified, only half (6) of the number of expected prekinetochores (12) was detected, circumstantially indicating at least transient association of homologous centromeres. Some nuclei showed clustering of centromeres at one pole (Rabl configuration). In metaphase chromosomes, each sister kinetochore contained a fluorescent spot. Western blotting of field bean nuclear proteins revealed four antigenic proteins of 28, 30, 64 and 68 kDa.