Biomaterial Database

Properties of in vitro transcription by isolated Xenopus oocyte nucleoli. 1979

H Saiga, and T Higashinakagawa

Some properties of in vitro transcription by isolated Xenopus oocyte nucleoli were described. When incubated with labeled RNA precursors, Xenopus oocyte nucleoli exhibited prolonged incorporation of radioactivity into RNA. The synthetic activity was exclusively due to type I RNA polymerase as revealed by its insensitivity to low and high doses of alpha-amanitin. The size of the in vitro transcript was mostly larger than 28S at 10 minute incubation and became smaller as incubation proceeded. When [gamma-32P]ATP was included in the reaction mixture, 32P radioactivity was incorporated into RNA suggesting the possible initiation of transcription in this system. However, analysis of the terminal nucleotide of the transcript revealed that the incorporation of radioactivity from [gamma-32P]ATP was not due to the initiation of transcription but due to polynucleotide kinase activity in the nucleolar preparation. These results demonstrate that the incorporation of radioactivity from [gamma-32P] labeled nucleoside triphosphates cannot necessarily be regarded as an index of the initiation of transcription.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D010063	Ovum	A mature haploid female germ cell extruded from the OVARY at OVULATION.	Egg,Egg, Unfertilized,Ova,Eggs, Unfertilized,Unfertilized Egg,Unfertilized Eggs
D011116	Polynucleotide 5'-Hydroxyl-Kinase	An enzyme that catalyzes the transfer of a phosphate group to the 5'-terminal hydroxyl groups of DNA and RNA. EC 2.7.1.78.	Polynucleotide Hydroxylkinase,Polynucleotide Kinase,5'-Hydroxylpolynucleotide Kinase,DNA 5'-Hydroxylkinase,DNA Kinase,Polynucleotide 5'-Hydroxyl Kinase,Polynucleotide Hydroxykinase,5' Hydroxylpolynucleotide Kinase,5'-Hydroxyl Kinase, Polynucleotide,5'-Hydroxyl-Kinase, Polynucleotide,5'-Hydroxylkinase, DNA,DNA 5' Hydroxylkinase,Hydroxykinase, Polynucleotide,Hydroxylkinase, Polynucleotide,Kinase, 5'-Hydroxylpolynucleotide,Kinase, DNA,Kinase, Polynucleotide,Kinase, Polynucleotide 5'-Hydroxyl,Polynucleotide 5' Hydroxyl Kinase
D002466	Cell Nucleolus	Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)	Plasmosome,Cell Nucleoli,Nucleoli, Cell,Nucleolus, Cell,Plasmosomes
D005260	Female		Females
D000546	Amanitins	Cyclic peptides extracted from carpophores of various mushroom species. They are potent inhibitors of RNA polymerases in most eukaryotic species, blocking the production of mRNA and protein synthesis. These peptides are important in the study of transcription. Alpha-amanitin is the main toxin from the species Amanitia phalloides, poisonous if ingested by humans or animals.	Amanitin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012318	RNA Polymerase I	A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. The enzyme functions in the nucleolar structure and transcribes DNA into RNA. It has different requirements for cations and salts than RNA polymerase II and III and is not inhibited by alpha-amanitin.	DNA-Dependent RNA Polymerase I,RNA Polymerase A,DNA Dependent RNA Polymerase I,Polymerase A, RNA,Polymerase I, RNA
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription