The Involvement of RNA in the Initiation of DNA Synthesis in Mammalian Cells. Artifacts Arising during Caesium-Salt Density-Gradient Centrifugation which Simulate a Covalent Attachment of RNA to Newly Synthesized DNA
- 1 March 1976
- journal article
- Published by Wiley in European Journal of Biochemistry
- Vol. 62 (3) , 451-459
- https://doi.org/10.1111/j.1432-1033.1976.tb10178.x
Abstract
Artifacts were encountered during caesium salt density gradient centrifugation which simulated results expected if newly synthesized DNA is covalently attached to RNA. Newly synthesized DNA (in baby hamster kidney cells, BHK-21/C13), pulse-labelled with [3H]thymidine for 10 min at temperatures below 25 degrees C, banded at a greater buoyant density than mature [14C]DNA (heat-denatured nucleic acids) when centrifuged to equilibrium in caesium chloride gradients. Some of the newly synthesized RNA, labelled with [3H]uridine, banded at a buoyant density slightly greater than DNA in caesium sulphate gradients. These results were not obtained when nucleic acids were pulse-labelled at 37 degrees C, nor when samples were heat-denatured in the presence of formaldehyde. This suggests that nucleic acids can aggregate during centrifugation; this is discussed in relation to the molecular size of the DNA.Keywords
This publication has 16 references indexed in Scilit:
- RNA-nascent DNA complexes in Ehrlich ascites tumor cells in vivoExperimental and Molecular Pathology, 1974
- Studies on nascent DNA in mouse myelomaCell, 1974
- DNA-directed and RNA-primed DNA synthesis in microsomal and mitochondrial fractions of normal human lymphocytesBiochemical and Biophysical Research Communications, 1974
- RNA-DNA covalent complexes in HeLa cellsBiochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis, 1974
- RNA in Nascent DNA from Cultured Human LymphocytesNature New Biology, 1973
- A covalently linked DNA-RNA molecule from human leukemia cellsBiochemical and Biophysical Research Communications, 1973
- RNA bound to nascent DNA in Ehrlich ascites tumor cellsBiochemical and Biophysical Research Communications, 1972
- RNA-Linked Nascent DNA Fragments in Escherichia coliProceedings of the National Academy of Sciences, 1972
- RNA Synthesis Initiates In Vitro Conversion of M13 DNA to Its Replicative FormProceedings of the National Academy of Sciences, 1972
- A Possible Role for RNA Polymerase in the Initiation of M13 DNA SynthesisProceedings of the National Academy of Sciences, 1971