Abstract
To help elucidate the role of protein in the maturation of ribosomal RNA in cultured L cells, we have studied the effects of cycloheximide upon the maturation process and upon the intranucleolar ribonucleoprotein particles containing the "preribosomal RNA's." Five parameters of these particles were analyzed: (a) extractability, (b) sedimentation characteristics in sucrose gradients, (c) RNA composition, (d) buoyant density in CsCl gradients, and (e) effects of increased ionic strength on the buoyant density. When protein synthesis is inhibited, the rate of conversion of the precursor 45S ribosomal RNA is rapidly diminished, falling to less than 30% of the control rate within 1 hr. Nevertheless, in terms of the first three parameters there is no difference between control and cycloheximide nucleolar particles. However, the cycloheximide particles have a lower and more heterogeneous buoyant density and a more variable response to increased ionic strength. The results imply that the protein composition of the cycloheximide particles is different from that of particles from control cells, and that the entire protein complement is not necessary for the first cleavages in the maturation process, although it is necessary for the normal rate of processing and for the eventual appearance of both 18S and 28S rRNA in mature ribosomes.
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- Baltimore D., Huang A. S. Interaction of HeLa cell proteins with RNA. J Mol Biol. 1970 Feb 14;47(3):263–273. doi: 10.1016/0022-2836(70)90301-3. [DOI] [PubMed] [Google Scholar]
- Darnell J. E., Jr Ribonucleic acids from animal cells. Bacteriol Rev. 1968 Sep;32(3):262–290. doi: 10.1128/br.32.3.262-290.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ennis H. L. Synthesis of ribonucleic acid in L cells during inhibition of protein synthesis by cycloheximide. Mol Pharmacol. 1966 Nov;2(6):543–557. [PubMed] [Google Scholar]
- Higashi K., Matsuhisa T., Kitao A., Sakamoto Y. Selective suppression of nucleolar RNA metabolism in the absence of protein synthesis. Biochim Biophys Acta. 1968 Sep 24;166(2):388–393. doi: 10.1016/0005-2787(68)90226-8. [DOI] [PubMed] [Google Scholar]
- Liau M. C., Perry R. P. Ribosome precursor particles in nucleoli. J Cell Biol. 1969 Jul;42(1):272–283. doi: 10.1083/jcb.42.1.272. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loening U. E. The fractionation of high-molecular-weight ribonucleic acid by polyacrylamide-gel electrophoresis. Biochem J. 1967 Jan;102(1):251–257. doi: 10.1042/bj1020251. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Maden B. E., Vaughan M. H., Warner J. R., Darnell J. E. Effects of valine deprivation on ribosome formation in HeLa cells. J Mol Biol. 1969 Oct 28;45(2):265–275. doi: 10.1016/0022-2836(69)90104-1. [DOI] [PubMed] [Google Scholar]
- Noll H. Characterization of macromolecules by constant velocity sedimentation. Nature. 1967 Jul 22;215(5099):360–363. doi: 10.1038/215360a0. [DOI] [PubMed] [Google Scholar]
- Penman S. RNA metabolism in the HeLa cell nucleus. J Mol Biol. 1966 May;17(1):117–130. doi: 10.1016/s0022-2836(66)80098-0. [DOI] [PubMed] [Google Scholar]
- Perry R. P., Kelley D. E. Buoyant densities of cytoplasmic ribonucleoprotein particles of mammalian cells: distinctive character of ribosome subunits and the rapidly labeled components. J Mol Biol. 1966 Apr;16(2):255–268. doi: 10.1016/s0022-2836(66)80171-7. [DOI] [PubMed] [Google Scholar]
- Perry R. P., Kelley D. E. Messenger RNA-protein complexes and newly synthesized ribosomal subunits: analysis of free particles and components of polyribosomes. J Mol Biol. 1968 Jul 14;35(1):37–59. doi: 10.1016/s0022-2836(68)80035-x. [DOI] [PubMed] [Google Scholar]
- Schleif R. F. Origin of chloramphenicol particle protein. J Mol Biol. 1968 Oct 14;37(1):119–129. doi: 10.1016/0022-2836(68)90077-6. [DOI] [PubMed] [Google Scholar]
- Spitnik-Elson P., Atsmon A. Detachment of ribosomal proteins by salt. I. Effect of conditions on the amount of protein detached. J Mol Biol. 1969 Oct 14;45(1):113–124. doi: 10.1016/0022-2836(69)90214-9. [DOI] [PubMed] [Google Scholar]
- Warner J. R., Soeiro R. Nascent ribosomes from HeLa cells. Proc Natl Acad Sci U S A. 1967 Nov;58(5):1984–1990. doi: 10.1073/pnas.58.5.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Warner J. R. The assembly of ribosomes in HeLa cells. J Mol Biol. 1966 Aug;19(2):383–398. doi: 10.1016/s0022-2836(66)80012-8. [DOI] [PubMed] [Google Scholar]
- Weinberg R. A., Loening U., Willems M., Penman S. Acrylamide gel electrophoresis of HeLa cell nucleolar RNA. Proc Natl Acad Sci U S A. 1967 Sep;58(3):1088–1095. doi: 10.1073/pnas.58.3.1088. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Willems M., Penman M., Penman S. The regulation of RNA synthesis and processing in the nucleolus during inhibition of protein synthesis. J Cell Biol. 1969 Apr;41(1):177–187. doi: 10.1083/jcb.41.1.177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yoshida K., Osawa S. Origin of the protein component of chlormaphenicaol particles in Escherichia coli. J Mol Biol. 1968 May 14;33(3):559–569. doi: 10.1016/0022-2836(68)90306-9. [DOI] [PubMed] [Google Scholar]
