Cytochemistry of satellite nucleoli in human lymphocytes

Satellite nucleoli of lymphocytes were studied to provide additional information on the cytochemistry of these nucleoli particularly with respect to the presence of rDNA and RNA polymerase I. According to the results of the in situ hybridization satellite nucleoli contain rDNA similarly as characteristic nucleoli. Immunostaining demonstrated that satellite nucleoli similarly as characteristic nucleoli possess RNA polymerase I in addition to proteins B23, C23 and fibrillarin. RNA of satellite nucleoli was detected in satellite as well as in characteristic nucleoli with buffered toluidine or methylene blue. The cytochemical evidence and morphology of satellite nucleoli strongly supports the supposition that these nucleoli represent solitary small nucleoli containing nucleolus organizer regions which did not participate in the formation of characteristic nucleoli.