Biomaterial Database

Evidence for a partial RNA transcript of the small circular component of kinetoplast DNA of Crithidia acanthocephali. 1979

D L Fouts, and D R Wolstenholme

The major component of kinetoplast DNA (kDNA) in the protozoan Crithidia acanthocephali is an association of approximately 27,000, 0.8 micrometers (1.58 x 10(6) dalton) circular molecules apparently held together in a particular structural configuration by topological interlocking. We have carried out hybridization experiments between kDNA samples containing one or the other of the two complementary (H and L) strands of purified 0.8 micrometers molecules derived from mechanically disrupted associations and RNA samples prepared either from whole C. acanthocephali cells or from a mitochondrion-enriched fraction. The results of experiments involving cesium sulfate buoyant density centrifugation indicate that whole cell RNA contains a component(s) complementary to all kDNA H strands, but none complementary to kDNA L strands. Similar results were obtained using mitochondrion-associated RNA. Digestion of RNA/DNA hybrids and suitable controls with the single-strand-specific nuclease S1 indicated that 10% of the kDNA H strand is involved in hybrid formation. Visualization of RNA/DNA hybrids stained with bacteriophage T4 gene 32 protein revealed that hybridation involves a single region of each kDNA H strand, equal to approximately 10% of the molecule length. These data suggest that at least 10% of the small circular component of kDNA of Crithidia acanthocephali is transcribed.

UI	MeSH Term	Description	Entries
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D003421	Crithidia	A genus of parasitic protozoans found in the digestive tract of invertebrates, especially insects. Organisms of this genus have an amastigote and choanomastigote stage in their life cycle.	Crithidias
D004270	DNA, Circular	Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)	Circular DNA,Circular DNAs,DNAs, Circular
D004272	DNA, Mitochondrial	Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.	Mitochondrial DNA,mtDNA
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
D012313	RNA	A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	RNA, Non-Polyadenylated,Ribonucleic Acid,Gene Products, RNA,Non-Polyadenylated RNA,Acid, Ribonucleic,Non Polyadenylated RNA,RNA Gene Products,RNA, Non Polyadenylated
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