Biomaterial Database

Activity of nuclear DNA-dependent RNA polymerases in mouse limb buds differentiating in vivo or in organ culture. 1976

D Neubert, and M Rautenberg

1) A method was developed to measure the activity of DNA dependent RNA polymerase reactions I (alpha-amanitin-insensitive) and II (alpha-amanitin-sensitive) in homogenates of very small amounts of tissue. This technique was used to study the activity of these polymerase reactions in limb buds from mouse embryos developing in vivo or in an organ culture system. This culture system allows the morphogenetic differentiation of limb buds in early stages of embryonic development (day 10-11 of gestation greater than or equal to 37 - 45 pairs of somites) from a blastema stage to well recognizable cartilaginous bone analgen. 2) An increase in the activities of both types of RNA polymerases was found to occur in vivo in limb buds on day 12 of gestation when compared with the activity measured on day 11 of gestation. A similar increase with a maximum about 24-48h after initiation of the cultures could be observed in the explants differentiating in organ culture. To our knowledge this is the first time that induction processes proceeding in mammalian embryonic tissues could be correlated with an increased activity of RNA polymerases. 3)A rough estimate shows that the rate of transcription due to RNA polymerase I measured in homogenates or in isolated nuclei (measured with substrate concentrations giving about 80% of the maximal rate) would account for the assumed rate of rRNA synthesis in vivo. The measurement of the RNA polymerase activity in isolated nuclei, thus, may give some information about the transcriptional processes occurring under "physiological" conditions. 4) The mammalian organ culture system presented provides a suitable model for studying embryonic differentiation processes.

UI	MeSH Term	Description	Entries
D009924	Organ Culture Techniques	A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)	Organ Culture,Culture Technique, Organ,Culture Techniques, Organ,Organ Culture Technique,Organ Cultures
D004622	Embryo, Mammalian	The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.	Embryonic Structures, Mammalian,Mammalian Embryo,Mammalian Embryo Structures,Mammalian Embryonic Structures,Embryo Structure, Mammalian,Embryo Structures, Mammalian,Embryonic Structure, Mammalian,Embryos, Mammalian,Mammalian Embryo Structure,Mammalian Embryonic Structure,Mammalian Embryos,Structure, Mammalian Embryo,Structure, Mammalian Embryonic,Structures, Mammalian Embryo,Structures, Mammalian Embryonic
D005121	Extremities	The farthest or outermost projections of the body, such as the HAND and FOOT.	Limbs,Extremity,Limb
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
D012319	RNA Polymerase II	A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. It functions in the nucleoplasmic structure and transcribes DNA into RNA. It has different requirements for cations and salt than RNA polymerase I and is strongly inhibited by alpha-amanitin. EC 2.7.7.6.	DNA-Dependent RNA Polymerase II,RNA Pol II,RNA Polymerase B,DNA Dependent RNA Polymerase II
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus