Three distinct RNA polymerase activities have been isolated from developing sea urchin embryos. In rat liver nuclei there are two RNA polymerase activities. One polymerase (I) is probably localized in the nucleolus and one (II) in the nucleoplasm.

Multiple Forms of DNA-dependent RNA Polymerase in Eukaryotic Organisms

Genetic aspects of bacterial endospore formation.

Publisher Summary This chapter explains the procedures for the isolation of nuclei, mitochondria, and lysosomes from cultured mammalian cell lines. Cultured Chinese hamster ovary (CHO) cells are routinely disrupted by low-pressure nitrogen cavitation. The cell pellets concentrate at the bottom of the bottles. All centrifugations are timed from when the rotor reaches running speed. The cavitated cells are homogenized with four strokes of a motor-driven pestle of a Potter–Elvehjem homogenizer. The motor drive is set so that the Teflon pestle almost stops turning as it reaches the bottom of the homogenizer. For the subsequent isolation of cytoplasmic organelles, nuclei and unbroken cells are rapidly separated from cytoplasmic organelles by differential sedimentation at low centrifugal force. Intact organelle membranes prevent substrate access to lumenal enzymes. Hence, organelle-specific enzyme activity is generally measured in the presence of nonionic detergent; comparison of enzyme activity in the presence and absence of detergent provides a quick method to assess organelle intactness.

Isolation of subcellular organelles.

Localization and kinetics of formation of nuclear heterodisperse RNA, cytoplasmic heterodisperse RNA and polyribosome-associated messenger RNA in HeLa cells

Fate of transforming DNA following uptake by competent Bacillus subtilis. I. Formation and properties of the donor-recipient complex.

A particulate fraction has been isolated from detergent-prepared HeLa cell nuclei. The fraction consists largely of organelles that resemble the nucleoli of intact cells. The 45S RNA that is precursor to 28S and 18S ribosomal RNA is associated with the fraction. The 32S RNA that is labeled after the 45S RNA and is the apparent precursor to 28S RNA is also associated with the fraction. The nucleoplasm contains 28S RNA that behaves as an intermediate between the 32S nucleolar RNA and the 28S cytoplasmic RNA.

https://science.sciencemag.org/content/sci/154/3750/786.full.pdf

Ribosomal RNA synthesis and processing in a particulate site in the HeLa cell nucleus.

Genetic mapping in Bacillus subtilis.

Electron microscopic studies of detergent-treated HeLa cell nuclei

Several antibiotic resistance markers in Bacillus subtilis have been mapped by three-factor transduction crosses using bacteriophage PBS1. These markers, which are thought to be located in genes coding for ribosomal proteins, are within a segment comprising about 5 per cent of the B. subtilis genetic map, close to the major group of rRNA cistrons. The order of genetic makers in this region was found to be cysA14 mic-1 † str-1 (ery-1, ole-2) spc-2 bry-2 lin-2. The positions of neo-2, nea-1, and kan-2 are uncertain, although they are located in this region to the right of cysA14.

https://www.pnas.org/content/pnas/65/1/96.full.pdf

Issar Smith

Papers

Ribosomal RNA synthesis and processing in a particulate site in the HeLa cell nucleus.

Genetic mapping in Bacillus subtilis.

Electron microscopic studies of detergent-treated HeLa cell nuclei

Genetic mapping of antibiotic resistance in markers Bacillus subtilis.

The Enzymatic Methylation of Ribonucleic Acid and Deoxyribonucleic Acid VII. THE METHYLATION OF RIBOSOMAL RIBONUCLEIC ACID