Biomaterial Database

Two distant regions of the Epstein-Barr virus genome with sequence homologies have the same orientation and involve small tandem repeats. 1982

J Hudewentz, and H Delius, and U K Freese, and U Zimber, and G W Bornkamm

The two regions of the Epstein-Barr virus genome (DSL and DSR) carrying homologous sequences at distant parts of the long unique region are described. Cleavage of cloned DNA containing the DSR region with restriction endonucleases revealed a so far unrecognized small tandem repeat of approximately 120 base pairs present in approximately 20 copies. Heteroduplexes of the DNA of two clones containing DSL and DSR respectively, visualized in the electron microscope by cytochrome c spreading, revealed that the region of homology is approximately 2.5 kb long, involves small tandem repeats, and has the same orientation in the viral genome. Mica adsorption of the heteroduplex showed, that the homologous region consists of approximately 1.5 kb with only partial homology including the small internal repeats and 0.9 kb with well-matched duplexes. When DNA containing the DSL region reanneals, it can give rise to two single-stranded loops of the same size at different positions suggesting the presence of a row of tandem repeats also in this region.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D012091	Repetitive Sequences, Nucleic Acid	Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).	DNA Repetitious Region,Direct Repeat,Genes, Selfish,Nucleic Acid Repetitive Sequences,Repetitive Region,Selfish DNA,Selfish Genes,DNA, Selfish,Repetitious Region, DNA,Repetitive Sequence,DNA Repetitious Regions,DNAs, Selfish,Direct Repeats,Gene, Selfish,Repeat, Direct,Repeats, Direct,Repetitious Regions, DNA,Repetitive Regions,Repetitive Sequences,Selfish DNAs,Selfish Gene
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004274	DNA, Recombinant	Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.	Genes, Spliced,Recombinant DNA,Spliced Gene,Recombinant DNA Research,Recombination Joint,DNA Research, Recombinant,Gene, Spliced,Joint, Recombination,Research, Recombinant DNA,Spliced Genes
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D004854	Herpesvirus 4, Human	The type species of LYMPHOCRYPTOVIRUS, subfamily GAMMAHERPESVIRINAE, infecting B-cells in humans. It is thought to be the causative agent of INFECTIOUS MONONUCLEOSIS and is strongly associated with oral hairy leukoplakia (LEUKOPLAKIA, HAIRY;), BURKITT LYMPHOMA; and other malignancies.	Burkitt Herpesvirus,Burkitt Lymphoma Virus,E-B Virus,EBV,Epstein-Barr Virus,Human Herpesvirus 4,Infectious Mononucleosis Virus,Burkitt's Lymphoma Virus,HHV-4,Herpesvirus 4 (gamma), Human,Burkitts Lymphoma Virus,E B Virus,E-B Viruses,Epstein Barr Virus,Herpesvirus, Burkitt,Infectious Mononucleosis Viruses,Lymphoma Virus, Burkitt,Mononucleosis Virus, Infectious,Mononucleosis Viruses, Infectious
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA