title: Insertion of L1 elements into sites that can form non-B DNA. Interactions of non-B DNA-forming sequences.
abstract: Three rat L1 element integration (target) sites chosen at random can adopt non-B DNA structures in vitro at normal bacterial superhelical densities. These target sites contain, respectively, short, mixed (AT)n tracts that we show can form one or more cruciforms, short (GT)n tracts, or polypurine:polypyrimidine regions. These sites share no sequence homology, and a non-B DNA structure appears to be the only feature common to them all. When the right end of the L1Rn3 element which forms a complex series of non-B DNA structures including two triplexes, and its target site which undergoes cruciform extrusion, are present on the same supercoiled molecule, they compete for available supercoil energy. The amount of non-B DNA formed at each site varies with pH, the concentration of cations, and the size of the topological domain. The implication of our findings for recombination of L1 elements and for the effect of these elements on contiguous DNA sequences is discussed.
authors.affiliation: Section on Genomic Structure and Function, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
authors.forename: K
authors.initials: K
authors.lastname: Usdin
authors.forename: A V
authors.initials: AV
authors.lastname: Furano
mesh_terms: D000079:Acetaldehyde / Q000494:pharmacology / Q000031:analogs & derivatives; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000187:drug effects / Q000235:genetics*; D004251:DNA Transposable Elements; D004279:DNA, Viral / Q000235:genetics; D005803:Genes, Immunoglobulin; D006863:Hydrogen-Ion Concentration; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D015636:Magnesium Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000187:drug effects; D051381:Rats; D015183:Restriction Mapping
chemical_list: D004251:DNA Transposable Elements; D004279:DNA, Viral; D007143:Immunoglobulin Heavy Chains; D015636:Magnesium Chloride; C038235:bromoacetaldehyde; D004247:DNA; D000079:Acetaldehyde