Showing papers on "Restriction map published in 1974"

The mapping and ordering of fragments of SV40 DNA produced by restriction endonucleases

Abstract: SV40 DNA is cleaved by the Eco RII and Hae restriction endonucleases to give rise to two different sets of 16 fragments each. These fragments have been ordered by analysis of the products of redigestion of one set of fragments with another restriction enzyme. The cleavage sites have been precisely mapped based on length measurements of the products of each cleavage. This provides a convenient group of small DNA fragments suitable for sequence analysis investigation of the transcripts present in infected cells, or construction of deletion substitution variants of the virus.

A Colinear Map Relating the Simian Virus 40 (SV40) DNA Segments of Six Adenovirus-SV40 Hybrids to the DNA Fragments Produced by Restriction Endonuclease Cleavage of SV40 DNA

Abstract: The simian virus 40 (SV40) DNA segments present in a series of adenovirus-SV40 hybrids have been mapped with respect to the sites of cleavage of SV40 DNA by restriction endonucleases. Two approaches have been used. First, nucleic acid hybridizations were performed between equimolar quantities of the denatured DNAs of SV40 and each hybrid virus and the radiolabeled transcripts of 11 DNA fragments obtained by cleavage of SV40 DNA by restriction endonuclease from Hemophilus influenzae. Secondly, selected fragments of SV40 DNA produced by the H. influenzae or H. parainfluenzae restriction endonucleases were used to form heteroduplex DNA molecules with adenovirus and adenovirus-SV40 hybrid DNA, which were then analyzed by electron microscopy. The two sets of data were consistent and have permitted alignment of the map of the SV40 segments of the hybrid viruses with the H. influenzae and H. parainfluenzae cleavage maps of SV40. Since cells infected with some of the hybrid viruses contain one or more SV40-specific antigens, the genetic determinants of these antigens could be localized on the cleavage map.

[24] Enzymatic methods for sequence analysis applied to DNA restriction and methylation sites

Abstract: Publisher Summary Restriction enzymes are site-specific endonucleases produced by various bacteria, bacterial plasmids, and viruses. In those cases where they produce double-stranded cleavage of DNA within their recognition sites, sequence analysis of the site is equivalent to determination of the 5'- and 3'-terminal bases of the restricted DNA. This chapter describes a method for limited sequencing of the 5' terminus of DNA molecules based on enzymatic cleavage of successively larger oligonucleotides. This procedure was developed especially for analysis of the end sequence of small restriction endonuclease fragments but should be more generally applicable to any small DNA molecule. Every host that produces a restriction endonuclease also produces a companion DNA modification enzyme, usually a methylase, with identical or similar site recognition. This enzyme serves to modify and protect the restriction sites of the host chromosome. The chapter concludes by describing a procedure for partial analysis of methylation sites.

Sites of cleavage by restriction enzymes in viral DNAs: comparison of observed and expected frequencies

Abstract: Observed frequencies of restriction enzyme cleavage in viral DNAs are compared to those expected from the cleavage site sequence and the known size and nearest neighbour frequencies of the DNAs. It is found that a number of significant deviations from expectation occur, and possible explanations are put forward.