Basic Enzymology of Transcription in Prokaryotes and Eukaryotes

Jacob, Samson T.; Rose, Kathleen M.

doi:10.1016/b978-0-12-289503-6.50010-2

Cited by 2 publications

(1 citation statement)

References 198 publications

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“…This compound is widely used to distinguish between the different eukaryotic RNA polymerases. It is now well established that RNA polymerase II is sensitive to low concentrations of 0~-amanitin (in the order of/~g/ml), while RNA polymerase III is inhibited by higher doses of 0c-amanitin (in the order of mg/ml) [ 15]. On the other hand, RNA polymerase I as well as chloroplastic and mitochondrial RNA polymerases are not affected by the inhibitor [15].…”

Section: The Endogenous Timer Acts At the Post-transcriptional Level mentioning

confidence: 99%

The early genetic response to light in the green unicellular alga Chlamydomonas eugametos grown under light/dark cycles involves genes that represent direct responses to light and photosynthesis

Gagné

Guertin

1992

Plant Mol Biol

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In the green unicellular alga Chlamydomonas eugametos, cellular division is readily synchronized by light/dark cycles. Under these conditions, light initiates photosynthetic growth in daughter cells and begins the G1 phase. Genes whose expression is regulated upon illumination are likely to be important mechanisms controlling cell proliferation. To identify some of those genes, two cDNA libraries were prepared with poly(A)+ extracted from cells either stimulated with light for 1 h or held in darkness (quiescent cells) during the same period. To restrict our analysis to those genes that are part of the primary response, cells were incubated in presence of cycloheximide. Differential screening of approximately 40,000 clones in each library revealed 44 clones which hybridize preferentially with a [32P] cDNA probe derived from RNA of light-stimulated cells and 15 clones which react selectively with a [32P] cDNA probe synthesized from poly(A)+ RNA of quiescent cells. Cross-hybridization of these clones identified 4 independent sequences in the light-induced (LI) collection and 2 in the uninduced (LR) library. Four of these cDNAs correspond to mRNAs that are positively or negatively regulated upon activation of photosynthesis. One clone represents a mRNA that accumulates transitorily at both transitions. Finally, LI818 cDNA identifies a new chlorophyll a/b-binding (cab) gene family whose mRNA accumulation is controlled by light and a circadian oscillator. The endogenous timing system controls LI818 mRNA accumulation so that it precedes the onset of illumination by a few hours. On the other hand, light affects LI818 mRNA levels independently of active photosynthesis.

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Section: The Endogenous Timer Acts At the Post-transcriptional Level mentioning

confidence: 99%

The early genetic response to light in the green unicellular alga Chlamydomonas eugametos grown under light/dark cycles involves genes that represent direct responses to light and photosynthesis

Gagné

Guertin

1992

Plant Mol Biol

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Phosphorylation of RNA polymerases: specific association of protein kinase NIl with RNA polymerase I

Rose

Stetler

Jacob

1983

Phil. Trans. R. Soc. Lond. B

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The activities of the three DNA-dependent RNA polymerases from a rapidly growing rat tumour, Morris hepatoma 3924A, and from rat liver were examined. The activity of RNA polymerase I was higher in the tumour than in the liver. The enhanced capacity for RNA synthesis was a result of a higher concentration of polymerase I in the tumour as well as of an activation of this enzyme in vivo. The possibility that the high specific activity of the hepatoma polymerase I resulted from phosphorylation was investigated. Two major cyclic-AMP-independent nuclear casein kinases (NI and NII) were identified; the activity of protein kinase NII in the tumour was ten times that in liver. Protein kinase NII was capable of activating and phosphorylating RNA polymerase I in vitro. This kinase could also stimulate RNA polymerase II activity, although to a lesser extent than RNA polymerase I. RNA polymerase III was not affected by protein kinase NII. Protein kinase NII was tightly associated with polymerase I and was found even in purified preparations of the polymerase. Antibodies against both RNA polymerase I and protein kinase NII were present in sera of patients with certain rheumatic autoimmune diseases. These results imply that RNA polymerase I and protein kinase NII are in close association in vivo as well as in vitro and that polymerase phosphorylation may regulate the rate of ribosomal RNA synthesis in the cell.

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Basic Enzymology of Transcription in Prokaryotes and Eukaryotes

Cited by 2 publications

References 198 publications

The early genetic response to light in the green unicellular alga Chlamydomonas eugametos grown under light/dark cycles involves genes that represent direct responses to light and photosynthesis

The early genetic response to light in the green unicellular alga Chlamydomonas eugametos grown under light/dark cycles involves genes that represent direct responses to light and photosynthesis

Phosphorylation of RNA polymerases: specific association of protein kinase NIl with RNA polymerase I

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