Effects of Thioacetamide on the Composition and Biosynthesis of Nucleolar and Nuclear Ribonucleic Acid in Rat Liver.
نویسندگان
چکیده
A number of studies have shown that the metabolic and proliferative properties of cells may be correlated with the size of their nucleoli (14). Generally, cells engaged in rapid protein synthesis or replication possess enlarged nucleoli. On the basis of morphological changes and autoradiographic studies, it has been suggested that the nucleolus is a site of rapid synthesis of ribonucleic acid and assembly of polysomes involved in protein synthesis (3-6). Transfer RNA (7), ribosomal RNA (8, 9), preribosomal RNA (5, 6)) and messenger RNA (10-12) have been implicated as products of nucleoli; it has also been suggested that they may be formed elsewhere and are stored in the nucleolus (4). Earlier studies from this and other laboratories have shown the profound increase in nucleolar RNA content (13, 14) and the marked stimulatory effect of thioacetamide on nucleolar RNA synthesis (13, 15) in liver cells. Since thioacetamide provides a reproducible means for increasing nucleolar size (14,16) and RNA content in liver cells, it seemed possible to carry out experiments on the intermediary events leading to changes in the types, composition, and rates of synthesis of nuclear and nucleolar RNA in the thioacetamide-treated cells. In this study it was found that administration of thioacetamide increased the nuclear RNA pool in liver, mainly by increasing the synthesis of guanineand cytosine-rich 35 S and 45 S RNA in the nucleolar fraction (Diagram 1). A preliminary report of these studies has been presented (15).
منابع مشابه
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 240 شماره
صفحات -
تاریخ انتشار 1965