Mitochondrial DNA of the ascomycete fungus Aspergillus nidulans, a circular molecule of 31 500 base pairs, is cleaved by restriction endonucleases Eco R I, Hind II, Hind III and Bgl II into 3, 7, 9 and 5 fragments, respectively. The relative positions of the cleavage sites could be mapped by analysis of fragments obtained by double enzyme digestions of whole DNA and by complete and partial redi...

Lampbrush chromosomes from oocytes of Notophthalmus viridescens were dispersed in media containing restriction endonucleases isolated from Haemophilus and E. coli. These endonucleases cleave duplex DNAs at specific palindromic sequences of nucleotides, and several sensitive sites occur per micron of DNA. The overwhelming majority of the lateral loops of lampbrush chromosomes are extensively fra...

We have cloned DNA restriction fragments from the largely nonessential region of bacteriophage T4 located between genes 39 and 56. The cloned DNA fragments were used to construct a precise map of the sites in this region recognized by eight restriction endonucleases. This restriction map allowed us to compare the cytosine-containing T4 DNA used for cloning with the hydroxymethylcytosine-contain...

A method for achieving strand specific nicking of DNA has been developed. Phosphorothioate groups were incorporated enzymatically into the (-)strand of M13 RF IV DNA. When such DNA is reacted with restriction endonucleases in the presence of ethidium bromide nicked DNA (RF II) is produced. All of the restriction enzymes tested linearised phosphorothioate-containing DNA in the absence of this dy...

REBASE is a comprehensive database of information about restriction enzymes, DNA methyltransferases and related proteins involved in the biological process of restriction-modification. It contains fully referenced information about recognition and cleavage sites, isoschizomers, neoschizomers, commercial availability, methylation sensitivity, crystal and sequence data. Experimentally characteriz...

BACKGROUND DNA fragments carrying internal recognition sites for the restriction endonucleases intended for cloning into a target plasmid pose a challenge for conventional cloning. RESULTS A method for directional insertion of DNA fragments into plasmid vectors has been developed. The target sequence is amplified from a template DNA sample by PCR using two oligonucleotides each containing a s...

Bacteriophage LL-H is a virulent phage of Lactobacillus lactis LL23. A restriction map of the phage genome was constructed with various restriction endonucleases. This chromosome has a 34-kilobase size and seems to be circularly permuted. We used a bank of LL-H restriction fragments to study the expression of five of the seven main phage particle proteins. Immunoblotting experiments permitted t...

More than 3000 type II restriction endonucleases have been discovered. They recognize short, usually palindromic, sequences of 4-8 bp and, in the presence of Mg(2+), cleave the DNA within or in close proximity to the recognition sequence. The orthodox type II enzymes are homodimers which recognize palindromic sites. Depending on particular features subtypes are classified. All structures of res...