The complete type II modification methylase of Agmenellum quadruplicatum was cloned in Escherichia coli as an R.Sau3A fragment of approximately 4.5 kilobases. The coding sequence was contained in a stretch of 1,156 base pairs which was organized into two parallel, partly overlapping open reading frames of 248 and 139 codons. In vivo complementation experiments showed that the synthesis of both predicted peptides was required for full methylase activity. The amino acid sequences were considerably similar to regions of other deoxycytidylate methylases.

A sequence-specific modification methylase (M . SinI) was isolated and purified from Escherichia coli harboring a derivative of recombinant plasmid pSI4 (see accompanying manuscript: C. Karreman and A. de Waard, J. Bacteriol. 170:2527-2532, 1988), which contains a Salmonella infantis DNA insert. The enzyme uniquely methylates the internal deoxycytidylate residue in the nucleotide sequence GG(A/T)MeCC, thereby protecting DNA completely against cleavage by restriction endonuclease R . SinI or R . AvaII [GG(A/T)CC], and in part against cleavage by R . Sau96I (GGNCC).

The complete type II restriction-modification system of Salmonella infantis was cloned in Escherichia coli as an R . Sau3AI fragment of 3,430 base pairs. The clone was shown to express the restriction endonuclease as well as the modification methylase. The nucleotide sequence of the above fragment showed two open reading frames of 461 and 230 codons in tail-to-tail orientation. These were shown to represent the modification methylase M . SinI and the restriction endonuclease R . SinI, respectively. The methylase M . SinI amino acid sequence revealed a considerable similarity to those of other deoxycytidylate methylases. In contrast, endonuclease R . SinI did not exhibit such a similarity to other restriction enzymes.

A sequence-specific modification methylase (M.AquI) was isolated and purified from Agmenellum quadruplicatum (Synechococcus PCC 7002). This enzyme uniquely methylates the deoxycytidylate residue in the sequence *CYCGRG indicated by the asterisk. It was shown to protect DNA against cleavage by restriction endonucleases AvaI, SmaI and XhoI, which recognize the sequences CYCGRG, CCCGGG, and CTCGAG, respectively.

Deinococcus radiophilus strain ATCC 27603 contains, apart from endonuclease DraI [1], two additional sequence‐specific endonucleases. These enzymes, designated DraII and DraIII, recognize nucleotide sequences with novel specificities, PuG↓GNCCPy and CACNN↓GTG, respectively.

A new sequence-specific endonuclease from the cyanobacterium Synechocystis species PCC 6701 has been purified and characterized. This enzyme, SecI, is unique in recognizing the nucleotide sequence: 5' -CCNNGG-3' 3' -GGNNCC-5' and cleaves it at the position indicated by the symbol. Two other restriction endonucleases, SecII and SecIII, found in this organism are isoschizomers of MspI and MstII, respectively.

The isolation of a new sequence‐specific endonuclease from a unicellular cyanobacterium is described. This enzyme specifically cleaves the nucleotide sequence GC‐↓TNAGC.

Clones encoding human adenosine deaminase (ADA) were isolated from a cDNA library made from the lymphoblastoid cell line MOLT-4. The isolation procedure was based on the selection of clones hybridizing with a radioactive probe complementary to an RNA preparation, which had been highly enriched in ADA-specific mRNA. The latter RNA preparation was obtained by size-fractionating MOLT-4 RNA and selecting fractions that were translatable into ADA. The assay for the presence of ADA in the in vitro translation products, was based on immunoprecipitation with a specific anti-ADA serum. The antiserum used was shown to precipitate a 42-kDal protein with the properties of ADA. Positive clones were further screened by means of hybrid-released in vitro translation assays. Two clones were obtained which were able to select mRNA that could be translated into a 42-kDal protein immunoprecipitable with the ADA-antiserum. By use of Southern blots containing DNA from somatic cell hybrids, one of these ADA cDNA clones was assigned to the human chromosome 20 known to contain the ADA gene.

The complements of restriction endonucleases of 12 strains of cyanobacteria were determined in cell-free extracts, and were compared with the complements of restriction activities assessed by measuring the relative efficiencies of plating of cyanophages on those cyanobacteria. The hosts which were susceptible to all of the phages contained endo R · AvaI and endo R · AvaII, and in several cases probably endo R · AvaIII, or isoschizomers of these enzymes. Three hosts which were lysed by only a subset (1 or 3) of the phages contained different restriction endonuclease. Anabaena sp. PCC 7120 showed apparent phenotypic restriction of phage An-22 grown in hosts with (isoschizomers of) AvaI, II and III, but no corresponding endonuclease has yet been detected in vitro. Nostoc sp. ATCC 29131 (PCC 6705) was found to contain a restriction enzyme, NspBII, with hitherot unknown specificity, C(A/C)GC(T/G)G.

Five nucleotide sequence-specific deoxyribonucleases present in cell-free extracts of the filamentous cyanobacterium Nostoc PCC7524 have been purified and characterized. One of these enzymes, designated Nsp(7524)I cleaves at a new kind of nucleotide sequence i.e. 5'-PuCATG λ Py-3'. The other four restriction enzymes in this organism, designated Nsp(7524)II, Nsp(1524)III, Nsp(1524)IV and Nsp(1524)V, are isoschizomers of enzymes which have been previously described. The cleavage site of Nsp(1524)ll which is an isoschizomer of SduI was determined.

Three nucleotide sequence-specific deoxyribonucleases present in extracts of Anabaena subcylindrica have been purified and characterized. Endo R·AsuI recognizes and cleaves the nucleotide sequence G↓GNCC (Hughes et al., 1980) while Endo R·AsuII and III split the sequences TT·CGAA and GPu↓CGPyC, respectively (this paper). An Anabaena strain “Waterbury” converging genetically at the 30–35% level with both A. subcylindrica and A. cylindrica (as judged by DNA-DNA hybridization, in vitro) was shown to possess the endonuclease pattern typical for A. cylindrica (de Waard et al., 1978). The usefulness of these specific endonucleases as taxonomic markers for the classification of cyanobacteria is discussed.

The structures of adenovirus type 7 (Ad7) cytoplasmic RNAs transcribed from the leftmost 4.5% of the viral genome during lytic infection of KB cells have been determined. The E1a region was found to specify three differently spliced mRNAs (I, II and III) which have common 5' and 3' termini. mRNAs I and II are transcribed between identical initiation and termination codons and code for polypeptides of 28 kd and 24 kd, whose only difference is an internal sequence of 31 amino acids present in the 28-kd protein. Translation of mRNA III initiates at the same AUG codon as in mRNA I and II, but uses a different reading frame beyond the splice point; consequently, it terminates at an earlier stop codon and yields a 6.3-kd polypeptide.

FEBS LettersVolume 117, Issue 1-2 p. 241-246 Full-length articleFree Access Two sequence-specific deoxyribonucleases from Rhodospirillum rubrum M.G.C. Duyvesteyn, M.G.C. Duyvesteyn Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorA. De Waard, A. De Waard Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorH. Van Ormondt, H. Van Ormondt Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this author M.G.C. Duyvesteyn, M.G.C. Duyvesteyn Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorA. De Waard, A. De Waard Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorH. Van Ormondt, H. Van Ormondt Laboratory for Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarsweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this author First published: August 11, 1980 https://doi.org/10.1016/0014-5793(80)80954-9Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume117, Issue1-2August 11, 1980Pages 241-246 ReferencesRelatedInformation

FEBS LettersVolume 101, Issue 1 p. 71-76 Full-length articleFree Access Two sequence-specific endonucleases from Anabaena oscillarioides First published: May 01, 1979 https://doi.org/10.1016/0014-5793(79)81298-3Citations: 12AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume101, Issue1May 01, 1979Pages 71-76 ReferencesRelatedInformation

Transformation by human adenoviruses is a process in which only a small fraction of the viral genome is involved. This is most clearly shown by the observation that specific DNA fragments originating from the left-hand end of the genome are able to transform cells in vitro (Graham et al. 1975; van der Eb et al. 1977; van der Eb and Houweling 1977). This is further supported by the finding that rodent cells transformed by human adenovirus types 2 or 5 (Ad2 or Ad5) all contain viral DNA sequences homologous to the left-hand 14% of the genome, whereas some of the lines also contain sequences homologous to other parts of the viral DNA (Gallimore et al. 1974; Sharp et al. 1975; Flint et al. 1976). This indicates that transformation is basically a function of early region 1 (E1), which maps between 1% and 11% in the DNA of all human adenoviral...

The primary structure of the HpaI-E fragment of adenovirus type 5 (Ad5) DNA has been determined, mainly by the method of Maxam and Gilbert (1977). This fragment comprises the leftmost 4.5% of the Ad5 genome, and has been shown to be the shortest DNA fragment capable of transforming cells. The identification of potential initiation and termination codons in the determined sequence indicates that two small polypeptides consisting of 186, and 81 amino acids, respectively, could be synthesized. Taking into account recent data on RNA splicing, a possibility is considered that this DNA may code also for larger polypeptides.

FEBS LettersVolume 96, Issue 1 p. 106-110 Full-length articleFree Access A new sequence-specific endonuclease from Anabaena cylindrica A. de Waard, A. de Waard Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorJ. Korsuize, J. Korsuize Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorC.P. van Beveren, C.P. van Beveren Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorJ. Maat, J. Maat Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this author A. de Waard, A. de Waard Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorJ. Korsuize, J. Korsuize Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorC.P. van Beveren, C.P. van Beveren Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this authorJ. Maat, J. Maat Laboratories of Physiological Chemistry, Sylvius Laboratories, University of Leiden, Wassenaarseweg 72, 2333 AL Leiden, The NetherlandsSearch for more papers by this author First published: December 01, 1978 https://doi.org/10.1016/0014-5793(78)81072-2Citations: 17 The authors dedicate this communication to Professor E. Havinga on the occasion of his retirement from Leyden University to which he has given so much. They also recognize his contributions to the independent development of biochemistry at this University AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 K.H. Murray, S.G. Hughes, J.S. Brown, S.A. Bruce, Biochem. J., 159, (1976), 317– 322. 2 Murray, K.H. (1978) personal communication. 3 B. Sugden, B. De Troy, R.J. Roberts, J. Sambrook, Anal. Biochem., 68, (1975), 36– 46. 4 B.G. Barrell, G.L. Cantoni D.R. Davis Procedures in Nucleic Acid Research 2, (1971), Harper and Row, Evanston London New York, San Francisco 751– 5 H. Van Ormondt, J. Maat, A. De Waard, A.J. Van der Eb, Gene, 4, (1978), in press 6 J. Maat, H.S.C. Lupker-Wille, Biochim. Biophys. Acta, (1978), in press 7 A.M. Maxam, W. Gilbert, Proc. Natl. Acad. Sci. USA, 74, (1977), 560– 564. 8 R. Bolivar, R.L. Rodriquez, P.J. Greene, M.C. Betlach, H.L. Heijneker, H.W. Boyer, J.H. Crosa, S. Falkow, Gene, 2, (1977), 95– 113. 9 R. Roberts, J.B. Breitmeyer, N.F. Tabachnik, P.A. Meyers, J. Mol. Biol., 91, (1975), 121– 123. 10 D.Tu. Chen-Pei, R. Roychoudhury, R. Wu, Biochem. Biophys. Res. Comm., 72, (1976), 355– 362. 11 W. Fiers, R. Contreras, R. Rogiers, F. Thijs, A. Van de Voorde, H. Van Heuverswijn, J. Van Herreweghe, G. Volckaert, M. Ysebaert, Nature, 273, (1978), 113– 120. 12 V.B. Reddy, B. Thimmappaya, R. Dhar, K.N. Subramanian, B.S. Zain, J. Pan, P.K. Ghosh, M.L. Celma, S.M. Weissman, Science, 200, (1978), 494– 502. 13 R.J. Roberts, P.A. Meyers, A. Morrison, K. Murray, J. Mol. Biol., 103, (1976), 199– 208. 14 J.G. Sutcliffe, Nucl. Acid Res., 5, (1978), 2721– 2728. Citing Literature Volume96, Issue1December 01, 1978Pages 106-110 ReferencesRelatedInformation