[Changes in the activity of different forms of RNA polymerase in the rat brain during postnatal development].

The dynamics of various forms of RNA-polymerases of the rat's brain was studied in the course of postnatal development, using autoradiography and fractionation of enzyme preparation purified from the matrix DNA admixture. In the brain of new-born rats, synthesis of ribosomal RNA proceeds more intensively, with form I enzyme being most active, due to a most active ribosomal RNA synthesis. As the brain develops, by the 12-14 days of life the activity of form I enzyme was found to decrease, whereas that of form II enzyme--to increase.

[DNA-dependent RNA-polymerase from loach embryos. Changes in the activity of forms I and II of the enzyme in the course of development].

The changes in the activity of form I and II DNA-dependent RNA-polymerases from the nuclei and cytoplasm in early embryos of loach (Misgurnus fossilis) were studied. Both forms of the polymerase activity were found in the nuclei at all stages of development including the morula stage, when the nuclear synthesis of RNA in vivo is practically absent. During an abrupt increase of transcription (the blastula stage), the total RNA polymerase activity of the nuclei is increased 10-15 fold per nucleus and more than 300-fold as calculated per total embryo nuclei.

[DNA-dependent RNA polymerases from loach embryos. General characteristics of cell-free RNA-synthesizing systems of different complexities].

The RNA-polymerase activity was solubilized and partially purified from embryo homogenates and from the nuclei and cytoplasm of developing loach (Misgurnus fossilis) embryos. In all preparations studied the two main forms of RNA-polymerase, i. e.