McrA and McrB restriction phenotypes of some E.coli strains and implications for gene cloning
TL;DR: Evidence is reviewed suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.
Abstract: The McrA and McrB (modified cytosine restriction) systems of E. coli interfere with incoming DNA containing methylcytosine. DNA from many organisms, including all mammalian and plant DNA, is expected to be sensitive, and this could interfere with cloning experiments. The McrA and B phenotypes of a few strains have been reported previously (1-4). The Mcr phenotypes of 94 strains, primarily derived from E. coli K12, are tabulated here. We briefly review some evidence suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.
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TL;DR: It is argued that the PrP gene modulates scrapie susceptibility, incubation times, and neuropathology, and synthesis of infectious scrapie prions programmed by a recombinant DNA molecule is demonstrated.
715 citations
01 Jan 1987
708 citations
TL;DR: The history and present situation of R-M, as well as other aspects of human evolution, are reviewed in detail.
Abstract: BIOLOGY OF RESTRICTION AND MODIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Restriction and modification enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Occurrence of R-M systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Restriction and modification of viruses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cloning restriction and modification genes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHARACTERISTICS OF R-M SySTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . Type I systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Type II systems . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . ...... . ...... . . .. . . . . . . . . . . . . .. . . . . . . . Type lIs systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Type III systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . f!::���:f�':rZ:::;i�g .;;�;��;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Regulation of expression . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . ...... . . . CONTRASTS AND COMPARISONS AMONG R-M SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . Type I systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Type II systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Type II endonucleases .. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . Methyltransferases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DiSCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
696 citations
TL;DR: This chapter discusses the major techniques and parameters that affect transformation of bacteria, focusing on E.coli, and the genetic constitution of the host strain of the organism being transformed.
Abstract: Publisher Summary Escherichia coli is a universal host organism both for molecular cloning of DNA and for a diverse set of assays involving clones genes. This chapter discusses the major techniques and parameters that affect transformation of bacteria, focusing on E.coli . There are two major parameters involved in efficiently transforming a bacterial organism. The first is the method used to induce competence for transformation. There are two primary technical variations in this method: chemical induction of competence and high-voltage electroshock treatment (electroporation). Both the characteristic of the cells being transformed and the purpose of the transformation affect the choice of method. The second major parameter is the genetic constitution of the host strain of the organism being transformed; a variety of genes can dramatically influence the outcome of transformation experiments.
633 citations
TL;DR: The discovery of a new class of restriction systems that specifically cut DNA carrying the modification signature of foreign cells, and the mechanisms developed by phages to avoid the restriction systems of their hosts are described.
624 citations
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TL;DR: New Escherichia coli host strains have been constructed for the E. coli bacteriophage M13 and the high-copy-number pUC-plasmid cloning vectors and mutations introduced into these strains improve cloning of unmodified DNA and of repetitive sequences.
14,954 citations
TL;DR: In vitro recombination techniques were used to construct a new cloning vehicle, pBR322, which is a relaxed replicating plasmid, does not produce and is sensitive to colicin E1, and carries resistance genes to the antibiotics ampicillin (Ap) and tetracycline (Tc).
5,235 citations
TL;DR: Intercistronic complementation was observed between three classes of restriction and modification mutants of E. coli B, indicating that at least three cistron (the ram cistrons) are involved in the genetic control of the [restriction and modification of DNA].
3,656 citations
TL;DR: Plasmid cloning vectors that enable insertion of DNA fragments between the inducible ara (arabinose) promoter and the lac (lactose) structural genes have been constructed and used for the detection and analysis of signals that control gene transcription.
2,442 citations
TL;DR: A sensitive and general technique has been devised for the dual purposes of cloning genes by using antibodies as probes and isolating unknown proteins encoded by cloned DNA using an expression vector that permits insertion of foreign DNA into the beta-galactosidase structural gene lacZ and promotes synthesis of hybrid proteins.
Abstract: A sensitive and general technique has been devised for the dual purposes of cloning genes by using antibodies as probes and isolating unknown proteins encoded by cloned DNA. The method uses an expression vector, lambda gt11 (lac5 nin5 cI857 S100), that permits insertion of foreign DNA into the beta-galactosidase structural gene lacZ and promotes synthesis of hybrid proteins. Efficient screening of antigen-producing clones in lambda gt11 recombinant cDNA libraries is achieved through lysogeny of the phage library in hflA (high-frequency lysogeny) mutant cells of Escherichia coli; lysogens produce detectable quantities of antigen on induction, even when plated at high cell densities. The vector is also designed to facilitate the isolation of proteins specified by previously cloned gene sequences. Hybrid proteins encoded by recombinant phage accumulate in strains defective in protein degradation (lon mutants) in amounts amenable to large-scale purification. Antibodies produced against the portion of the hybrid encoded by foreign DNA could in turn be used to isolate the native polypeptide from eukaryotic cells.
1,998 citations