| Abstract: | Normal human fibroblasts aged during serial passage in cell culture are known to display a reduction in total RNA synthetic activity. We have used “ghost monolayers”, which have been stripped of cytoplasm, in order to determine by autoradiographic techniques whether this decreased synthetic activity in aged cells could be localized to particular structures within the nuclei. Results indicated that the age-related decline in RNA synthesis was entirely due to decreased synthesis of nucleolar RNA, while nucleoplasmic synthesis was unchanged. |
