ARN

@article{,

title = {Selection of tRNA(Asp) amber suppressor mutants having alanine, arginine, glutamine, and lysine identity},

author = {F Martin and J Reinbolt and G Dirheimer and J Gangloff and G Eriani},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8809018},

isbn = {8809018},

year  = {1996},

date = {1996-01-01},

journal = {RNA},

volume = {2},

number = {9},

pages = {919-927},

abstract = {Elements that confer identity to a tRNA in the cellular environment, where all aminoacyl-tRNA synthetases are competing for substrates, may be delineated by in vivo experiments using suppressor tRNAs. Here we describe the selection of active Escherichia coli tRNAAsp amber mutants and analyze their identity. Starting from a library containing randomly mutated tRNA(CUA)Asp genes, we isolated four amber suppressors presenting either lysine, alanine, or glutamine activity. Two of them, presenting mainly alanine or lysine activity, were further submitted to a second round of mutagenesis selection in order to improve their efficiency of suppression. Eleven suppressors were isolated, each containing two or three mutations. Ten presented identities of the two parental mutants, whereas one had switched from lysine to arginine identity. Analysis of the different mutants revealed (or confirmed for some nucleotides) their role as positive and/or negative determinants in AlaRS, LysRS, and ArgRS recognition. More generally, it appears that tRNAAsp presents identity characteristics closely related to those of tRNALys, as well as a structural basis for acquiring alanine or arginine identity upon moderate mutational changes; these consist of addition or suppression of the corresponding positive or negative determinants, as well as tertiary interactions. Failure to isolate aspartic acid-inserting suppressors is probably due to elimination of the important G34 identity element and its replacement by an antideterminant when changing the anticodon of the tRNAAsp to the CUA triplet.},

note = {1355-8382 

Journal Article},

keywords = {Alanine/genetics  Arginine/genetics  Base Sequence  Escherichia coli/genetics  Genes, Asp/*genetics  *Selection (Genetics)  Support, ERIANI, Genetic, Genetic  Molecular Sequence Data  *Mutation  RNA, Non-U.S. Gov't  *Suppression, Suppressor  Glutamine/genetics  Lysine/genetics  Models, Transfer, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The expression of E.coli threonyl-tRNA synthetase is regulated at the translational level by symmetrical operator-repressor interactions},

author = {P Romby and J Caillet and C Ebel and C Sacerdot and M Graffe and F Eyermann and C Brunel and H Moine and C Ehresmann and B Ehresmann and M Springer},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8918475},

isbn = {8918475},

year  = {1996},

date = {1996-01-01},

journal = {EMBO J},

volume = {15},

number = {21},

pages = {5976-5987},

abstract = {Threonyl-tRNA synthetase from Escherichia coli represses the translation of its own mRNA by binding to the operator region located upstream from the ribosome binding site. The operator contains two stemloop structures which interact specifically with the homodimeric enzyme. Here, we provide in vitro and in vivo evidence that these two stem-loop structures are recognized by the enzyme in an analogous way and mimic the anticodon arm of E.coli tRNA(Thr). Determination of the stoichiometry of the different RNA-threonyl-tRNA synthetase complexes reveals that two tRNA(Thr) molecules bind to the enzyme whereas only one thrS operator interacts with the homodimeric enzyme. A model is presented in which the two anticodon-like domains of the operator bind symmetrically to the two tRNA(Thr) anticodon recognition sites (one per subunit) of the dimeric threonyl-tRNA synthetase. Although symmetrical operator-repressor interactions in transcriptional control are widespread, this report stresses the importance of such interactions in translational regulation of gene expression.},

note = {0261-4189 

Journal Article},

keywords = {Anticodon  Base Sequence  Binding Sites  Binding, Bacterial  Gene Expression Regulation, Bacterial/chemistry/genetics/metabolism  RNA, Biological  Molecular Sequence Data  Mutagenesis, Competitive  Escherichia coli/*enzymology/*genetics/metabolism  Gene Expression Regulation, Enzymologic  Models, Genetic, Messenger/genetics/metabolism  Repressor Proteins/genetics  Support, Non-U.S. Gov't  Threonine-tRNA Ligase/*genetics  Translation, ROMBY, Site-Directed  Nucleic Acid Conformation  Operator Regions (Genetics)  RNA, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The use of chemical modification interference and inverse PCR mutagenesis to identify the dimerization initiation site of HIV-1 genomic RNA},

author = {J C Paillart and E Skripkin and B Ehresmann and C Ehresmann and R Marquet},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8786995},

isbn = {8786995},

year  = {1996},

date = {1996-01-01},

journal = {Pharm Acta Helv},

volume = {71},

number = {1},

pages = {21-28},

abstract = {The retroviral genome consists of two identical RNA molecules physically linked together close to their 5' end, in a region called the Dimer Linkage Structure (DLS). Recent findings suggest that dimerization is involved in encapsidation, regulation of translation and reverse transcription. Previous in vitro studies localized the DLS of HIV-1 in a region downstream of the splice donor (SD) site. More recently, we showed that dimerization of HIV-1 RNA also involves sequences upstream of the SD site. Modification interference experiments and site-directed mutagenesis were used to identify the nucleotides required in the dimerization process of HIV-1 RNA. Our results point out a self-complementary sequence located in a hairpin loop, between the Primer Binding Site (PBS) and the SD site, as the Dimerization Initiation Site.},

note = {0031-6865 

Journal Article},

keywords = {Base Sequence  *Genome, MARQUET, Non-U.S. Gov't, PAILLART, Site-Directed  Polymerase Chain Reaction  RNA, Unité ARN, Viral  HIV-1/*chemistry  Human  Molecular Sequence Data  Mutagenesis, Viral/*chemistry  Support},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {The crystallization of biological macromolecules from precipitates: evidence for Ostwald ripening.},

author = {J D Ng and B Lorber and J Witz and A Théobald-Dietrich and D Kern and R Giege},

url = {http://www.sciencedirect.com/science/article/pii/0022024896003624},

isbn = {10.1016/0022-0248(96)00362-4},

year  = {1996},

date = {1996-01-01},

journal = {J Crystal Growth},

volume = {168},

number = {1-4},

pages = {50-62},

abstract = {Crystals were obtained by different methods under conditions where nucleation and growth occur from precipitated macromolecular material. The phenomenon was observed with compounds of different size and nature, such as thaumatin, concanavalin A, an α-amylase, a thermostable aspartyl-tRNA synthetase, the nucleo-protein complex between a tRNAAsp transcript and its cognate yeast aspartyl-tRNA synthetase, and tomato bushy stunt virus. In each system, after a rather rapid precipitation step at high supersaturation lasting one to several days, a few microcrystals appear after prolonged equilibration at constant temperature. With α-amylase, the virus and the thermostable synthetase, crystallization is accompanied by appearance of depletion zones around the growing crystals and growth of the largest crystals at the expense of the smaller ones. These features are evidences for crystal growth by Ostwald ripening. In the case of thaumatin, concanavalin A and the nucleo-protein complex, crystallization occurs by a phase transition mechanism since it is never accompanied by the disappearance of the smallest crystals. A careful analysis with thermostable aspartyl-tRNA synthetase indicates that its crystallization at 4°C under high supersaturation starts by a phase transition mechanism with the formation of small crystals within an amorphous protein precipitate. Ostwald ripening follows over a period of up to three/four months with a growth rate of about 0.8 Å/s that is 13 times slower than that of crystals growing at 20°C in the absence of precipitate without ripening. At the end of the ripening process at 4°C, only one unique synthetase crystal remains per microassay with dimensions as large as 1 mm.},

keywords = {* Protein  * Virus  * Crystallization  * Growth kinetics  * Ostwald ripening, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Visualizing the logic behind RNA self-assembly},

author = {F Michel and E Westhof},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8830411},

isbn = {8830411},

year  = {1996},

date = {1996-01-01},

journal = {Science},

volume = {273},

number = {5282},

pages = {1676-1677},

note = {0036-8075 

Comment 

Journal Article},

keywords = {Animals  Base Composition  Crystallography, Catalytic/*chemistry  RNA, Protozoan/*chemistry  Tetrahymena/genetics, Unité ARN, X-Ray  Introns  *Nucleic Acid Conformation  RNA},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Selection of tRNA(Asp) amber suppressor mutants having alanine, arginine, glutamine, and lysine identity},

author = {F Martin and J Reinbolt and G Dirheimer and J Gangloff and G Eriani},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8809018},

isbn = {8809018},

year  = {1996},

date = {1996-01-01},

journal = {RNA},

volume = {2},

number = {9},

pages = {919-927},

abstract = {Elements that confer identity to a tRNA in the cellular environment, where all aminoacyl-tRNA synthetases are competing for substrates, may be delineated by in vivo experiments using suppressor tRNAs. Here we describe the selection of active Escherichia coli tRNAAsp amber mutants and analyze their identity. Starting from a library containing randomly mutated tRNA(CUA)Asp genes, we isolated four amber suppressors presenting either lysine, alanine, or glutamine activity. Two of them, presenting mainly alanine or lysine activity, were further submitted to a second round of mutagenesis selection in order to improve their efficiency of suppression. Eleven suppressors were isolated, each containing two or three mutations. Ten presented identities of the two parental mutants, whereas one had switched from lysine to arginine identity. Analysis of the different mutants revealed (or confirmed for some nucleotides) their role as positive and/or negative determinants in AlaRS, LysRS, and ArgRS recognition. More generally, it appears that tRNAAsp presents identity characteristics closely related to those of tRNALys, as well as a structural basis for acquiring alanine or arginine identity upon moderate mutational changes; these consist of addition or suppression of the corresponding positive or negative determinants, as well as tertiary interactions. Failure to isolate aspartic acid-inserting suppressors is probably due to elimination of the important G34 identity element and its replacement by an antideterminant when changing the anticodon of the tRNAAsp to the CUA triplet.},

note = {1355-8382 

Journal Article},

keywords = {Alanine/genetics  Arginine/genetics  Base Sequence  Escherichia coli/genetics  Genes, Asp/*genetics  *Selection (Genetics)  Support, ERIANI, Genetic, Genetic  Molecular Sequence Data  *Mutation  RNA, Non-U.S. Gov't  *Suppression, Suppressor  Glutamine/genetics  Lysine/genetics  Models, Transfer, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Structure of 4.5S RNA in the signal recognition particle of Escherichia coli as studied by enzymatic and chemical probing},

author = {G Lentzen and H Moine and C Ehresmann and B Ehresmann and W Wintermeyer},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8608448},

isbn = {8608448},

year  = {1996},

date = {1996-01-01},

journal = {RNA},

volume = {2},

number = {3},

pages = {244-253},

abstract = {The structure of 4.5S RNA, the Escherichia coli homologue of the signal recognition particle (SRP) RNA, alone and in the SRP complex with protein P48 (Ffh) was probed both enzymatically and chemically. The molecule is largely resistant against single strand-specific nucleases, indicating a highly base paired structure. Reactivity appears mainly in the apical tetraloop and in one of the conserved internal loops. Although some residues are found reactive toward dimethylsulphate and kethoxal in regions predicted to be unpaired by the phylogenetic secondary structure model of 4.5S RNA, generally the reactivity is low, and some residues in internal loops are not reactive at all. RNase V1 cleaves the RNA at multiple sites that coincide with predicted helices, although the cleavages show a pronounced asymmetry. The binding of protein P48 to 4.5S RNA results in a protection of residues in the apical part of the molecule homologous to eukaryotic SRP RNA (domain IV), whereas the cleavages in the conserved apical tetraloop are not protected. Hydroxyl radical treatment reveals an asymmetric pattern of backbone reactivity; in particular, the region encompassing nucleotides 60-82, i.e., the 3' part of the conserved domain IV, is protected. The data suggest that a bend in the domain IV region, most likely at the central asymmetric internal loop, is an important element of the tertiary structure of 4.5S RNA. Hyperchromicity and lead cleavage data are consistent with the model as they reveal the unfolding of a higher-order structure between 30 and 40 degrees C. Protection by protein P48 occurs in this region of the RNA and, more strongly, in the 5' part of domain IV (nt 26-50, most strongly from 35 to 49). It is likely that P48 binds to the outside of the bent form of 4.5S RNA.},

note = {1355-8382 

Journal Article},

keywords = {Bacterial Proteins/chemistry/metabolism  Base Sequence  Escherichia coli/*chemistry  *Escherichia coli Proteins  Hydroxyl Radical  Lead  Molecular Sequence Data  *Nucleic Acid Conformation  Nucleic Acid Denaturation  RNA, Bacterial/*chemistry/metabolism  Ribonucleases  Signal Recognition Particle/*chemistry/metabolism  Support, Non-U.S. Gov't, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Structural and functional evidence that initiation and elongation of HIV-1 reverse transcription are distinct processes},

author = {J M Lanchy and C Isel and C Ehresmann and R Marquet and B Ehresmann},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9150889},

isbn = {9150889},

year  = {1996},

date = {1996-01-01},

journal = {Biochimie},

volume = {78},

number = {11-12},

pages = {1087-1096},

abstract = {Retroviral reverse transcription starts with the extension of a cellular tRNA primer bound near the 5' end of the viral genomic RNA at a site called the primer binding site (PBS). Formation of the HIV-1 initiation complex between tRNA3(Lys), viral RNA and reverse transcriptase probably occurs during encapsidation of these components. tRNA3(Lys) is thought to be selectively packaged by interaction with the reverse transcriptase domain of the Pr160Gag-Pol precursor protein, then annealed to the PBS of viral RNA with the help of the nucleocapsid protein. tRNA3(Lys) and HIV-1 viral RNA form a highly-structured complex, with extended interactions between the two molecules. Two different modes of reverse transcription have been distinguished: initiation, a tRNA3(Lys)-specific and distributive mode of polymerization corresponding to the addition of the first five nucleotides, followed by elongation, a non-specific and processive mode of DNA synthesis. These two modes are reminiscent of the initiation and elongation processes previously observed with DNA-dependent RNA polymerases.},

note = {0300-9084 

Journal Article 

Review 

Review, Tutorial},

keywords = {Amino Acyl/*biosynthesis/*chemistry  RNA, Base Sequence  Comparative Study  HIV-1/*genetics/*metabolism  HIV-1 Reverse Transcriptase/*metabolism  Human  Molecular Sequence Data  *Nucleic Acid Conformation  RNA, Genetic, MARQUET, Non-U.S. Gov't  *Transcription, Transfer, Unité ARN, Viral/biosynthesis/chemistry  Retroviridae/metabolism  Support},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Specific initiation and switch to elongation of human immunodeficiency virus type 1 reverse transcription require the post-transcriptional modifications of primer tRNA3Lys},

author = {C Isel and J M Lanchy and S F Le Grice and C Ehresmann and B Ehresmann and R Marquet},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8631312},

isbn = {8631312},

year  = {1996},

date = {1996-01-01},

journal = {EMBO J},

volume = {15},

number = {4},

pages = {917-924},

abstract = {Initiation of RNA-dependent DNA synthesis by retroviral reverse transcriptases is generally considered as unspecific. In the case of human immunodeficiency virus type 1 (HIV-1), the natural primer is tRNA3Lys. We recently found evidence of complex interactions between tRNA3Lys and HIV-1 RNA that may be involved in the priming process. In this study, we compare the ability of natural and unmodified synthetic tRNA3Lys and 18mer oligoribo- and oligodeoxyribonucleotides complementary to the viral primer binding site to initiate replication of HIV-1 RNA using either homologous or heterologous reverse transcriptases. We show that HIV-1 RNA, HIV-1 reverse transcriptase and primer tRNA3Lys form a specific initiation complex that differs from the unspecific elongation complex formed when an oligodeoxyribonucleotide is used as primer. Modified nucleosides of tRNA3Lys are required for efficient initiation and transition to elongation. Transition from initiation to elongation, but not initiation of reverse transcription itself, is facilitated by extended primer-template interactions. Elongation, but not initiation of reverse transcription, is inhibited by Mn2+, which further differentiates these two different functional states of reverse transcriptase. These results define initiation of reverse transcription as a target to block viral replication.},

note = {0261-4189 

Journal Article},

keywords = {Cell-Free System  Gene Expression Regulation, Genetic  *Virus Replication, Lys/*metabolism  RNA, MARQUET, Non-U.S. Gov't  Templates, Transfer, Unité ARN, Viral  HIV-1/*genetics  HIV-1 Reverse Transcriptase  RNA, Viral/metabolism  RNA-Directed DNA Polymerase/*metabolism  Support},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Solution structure of mRNA hairpins promoting selenocysteine incorporation in Escherichia coli and their base-specific interaction with special elongation factor SELB},

author = {A Huttenhofer and E Westhof and A Bock},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8634916},

isbn = {8634916},

year  = {1996},

date = {1996-01-01},

journal = {RNA},

volume = {2},

number = {4},

pages = {354-366},

abstract = {On the basis of chemical probing data, the solution structures of RNA hairpins within fdhF and fdnG mRNAs in Escherichia coli, which both promote selenocysteine incorporation at UGA codons, were derived with the help of computer modeling. We find that these mRNA hairpins contain two separate structural domains that possibly also exert two different functions. The first domain is comprised of the UGA codon, which is included within a complex and distorted double-stranded region. Thereby, release factor 2 might be prevented from binding to the UGA codon to terminate protein synthesis. The second domain is located within the apical loop of the mRNA hairpin structures. This loop region exhibits a defined tertiary structure in which no base is involved in Watson-Crick interactions. The structure of the loop is such that, following a sharp turn after G22 (A22 in fdnG mRNA), bases G23 and U24 are exposed to the solvent on the deep groove side of the supporting helix. Residues C25 and U26 close the loop with a possible single H-bonding interaction between the first and last residues of the loop, 04(U26) and N6(A21). The bulge residues U17 and U18 (in fdhF mRNA), or Ul7 only in fdnG mRNA, point their Watson-Crick positions in the same direction as loop residues G23 and U24 do, and at the same time open up the deep groove at the top of the hairpin helix. Chemical probing data demonstrate that bases G23 and U24 in both mRNA hairpins, as well as residues U17 and Ul7/U18 (for fdhF mRNA) located in a bulge 5' to the loop, are involved directly in binding to special elongation factor SELB in both mRNAs. Therefore, SELB recognizes identical bases within both mRNA hairpins despite differences in their primary sequence, consistent with the derived 3D models for these mRNAs, which exhibit similar tertiary structures. Binding of SELB to the fdhF mRNA hairpin was estimated to proceed with an apparent Kd of 30 nM.},

note = {1355-8382 

Journal Article},

keywords = {Messenger/*chemistry  Selenocysteine/*metabolism  Solutions  Sulfuric Acid Esters/chemistry  Support, Non-U.S. Gov't, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {RNAs mediating cotranslational insertion of selenocysteine in eukaryotic selenoproteins},

author = {N Hubert and R Walczak and C Sturchler and E Myslinski and C Schuster and E Westhof and P Carbon and A Krol},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8955902},

isbn = {8955902},

year  = {1996},

date = {1996-01-01},

journal = {Biochimie},

volume = {78},

number = {7},

pages = {590-596},

abstract = {Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. Its biosynthesis and cotranslational insertion into selenoproteins is performed by an outstanding mechanism, implying the participation of several gene products. The tRNA(Sec) is one of these. In eukaryotes, its transcription mode by RNA polymerase III differs from that of classical tRNA genes, both at the level of the promoter elements and transcription factors involved. In addition, enhanced transcription is afforded by a newly characterized zinc finger activator. Not only transcription of the gene, but also the tRNA(Sec) itself is atypical since its 2D and 3D structures exhibit features which set it apart from classical tRNAs. Decoding of eukaryotic selenocysteine UGA codons requires a stem-loop structure in the 3'UTR of mRNAs, the selenocysteine insertion sequence (SECIS) element. Structure probing and sequence comparisons led us to propose a 2D structure model for the SECIS element, containing a novel RNA motif composed of four consecutive non-Watson-Crick base-pairs. A 3D model, rationalizing the accessibility data, was elaborated by computer modeling. It yields indicative or suggestive evidence for the role that could play some conserved residues and/or structural features in SECIS function. These might act as signals for interaction with SBP, the SECIS binding protein that we have characterized.},

note = {0300-9084 

Journal Article 

Review 

Review, Tutorial},

keywords = {Amino Acid-Specific/chemistry/metabolism  Rats  Schistosoma mansoni  Selenocysteine/chemistry/*metabolism  Support, Animals  Base Sequence  Cattle  Escherichia coli  Human  Mice  Models, Molecular  Molecular Sequence Data  Nucleic Acid Conformation  Proteins/chemistry/*metabolism  RNA/chemistry/*metabolism  RNA, Non-U.S. Gov't  Xenopus laevis, Transfer, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Role of RNA primers in initiation of minus-strand and plus-strand DNA synthesis of the yeast retrotransposon Ty1},

author = {S Friant and T Heyman and F X Wilhelm and M Wilhelm},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8955910},

isbn = {8955910},

year  = {1996},

date = {1996-01-01},

journal = {Biochimie},

volume = {78},

number = {7},

pages = {674-680},

abstract = {The Ty1 retrotransposon of the yeast Saccharomyces cerevisiae is a long terminal repeat mobile genetic element that transposes through an RNA intermediate. Initiation of minus-strand and plus-strand DNA synthesis are two critical steps during reverse transcription of the retrotransposon genome. Initiation of minus-strand DNA synthesis of the Ty1 element is primed by the cytoplasmic initiator methionine tRNA base paired to the primer binding site near the 5' end of the genomic RNA. A structural probing study of the primer tRNA-Ty1 RNA binary complex reveals that besides interactions between the primer binding site and the last 10 nucleotides at the 3' end of the primer tRNA, three short regions of Ty1 RNA named box 0, box 1 and box 2.1 interact with the T and D stems and loops of the primer tRNA. Some in vivo results underline the functional importance of the nucleotide sequence of the boxes and suggest that extended interactions between genomic Ty1 RNA and the primer tRNA play a role in the reverse transcription pathway. Plus-strand DNA synthesis is initiated from an RNase H resistant oligoribonucleotide spanning a purine-rich sequence, the polypurine tract (PPT). Two sites of initiation located at the 5' boundary of the 3' long terminal repeat (PPT1) and near the middle of the TyB (pol) gene in the integrase coding sequence (PPT2) have been identified in the genome of Ty1. The two PPTs have an identical sequence, TGGGTGGTA. Mutations replacing purines by pyrimidines in this sequence significantly diminish or abolish initiation of plus-strand DNA synthesis. Ty1 elements bearing a mutated PPT2 sequence are not defective for transposition whereas mutations in PPT1 abolish transposition.},

note = {0300-9084 

Journal Article},

keywords = {*DNA Replication  *DNA Transposable Elements  DNA, Bacterial/*metabolism  Support, Complementary/metabolism  Molecular Sequence Data  Mutagenesis  Nucleic Acid Conformation  RNA/*metabolism  RNA, Non-U.S. Gov't, Unité ARN},

pubstate = {published},

tppubtype = {article}

}