The nucleotide sequence in the promoter region of the gene for an Escherichia coli tyrosine transfer ribonucleic acid.

Journal of Biological Chemistry (Impact Factor: 4.65). 09/1976; 251(15):4481-9.
Source: PubMed

ABSTRACT The sequence of the first 29 nucleotides in the promoter region of a tyrosine tRNA gene has previously been determined (Sekiya, T., van Ormondt, H., and Khorana, H.G. (1975) J. Biol. Chem. 250, 1087-1098). This work has now been extended to give the sequence of a total of 59 nucleotides; the sequence is as follows: (see article). The general approach used in the determination of the sequence involved the DNA polymerase I-catalyzed elongation of synthetic deoxyribopolynucleotide primers hydridized to the l-strand of phi80psu+III DNA at the appropriate site. Sequencing of the newly added nucleotides was facilitated by the use of a number of techniques including (a) elongation of the primer with the use of all of the four nucleoside 5'-triphosphates but limiting the concentration of one of the triphosphates, (b) insertion of ribonucleotide units at appropriate sites so as to permit subsequent specific cleavages by pancreatic RNase, and (c) two-dimensional fingerprinting of the oligonucleotides in conjunction with partial exonucleolytic degradation, comprehensive nearest neighbor analyses, and the determination of pyrimidine tracts.

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    ABSTRACT: We have identified the region within a eukaryotic tRNA gene required for initiation of transcription. These results were obtained by systematically constructing deletions extending from the 5' or the 3' flanking regions into a cloned Drosophila tRNAArg gene by using nuclease BAL 31. The ability of the newly generated deletion clones to direct the in vitro synthesis of tRNA precursors was measured in transcription systems from Xenopus laevis oocytes, Drosophila Kc cells, and HeLa cells. Two control regions within the coding sequence were identified. The first was essential for transcription and was contained between nucleotides 8 and 25 of the mature tRNA sequence. Genes devoid of the second control region, which was contained between nucleotides 50 and 58 of the mature tRNA sequence, could be transcribed but with reduced efficiency. Thus, the promoter regions within a tRNA gene encode the tRNA sequences of the D stem and D loop, the invariant uridine at position 8, and the semi-invariant G-T-psi-C sequence.
    Proceedings of the National Academy of Sciences 12/1981; 78(11):6657-61. · 9.81 Impact Factor
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    ABSTRACT: We have cloned the Escherichia coli tyrosine-inserting amber suppressor tRNA gene into the recombinant single-strand phage M12mp3. By using the M13mp3SuIII+ recombinant phage DNA as template and an oligonucleotide bearing a mismatch as primer, we have synthesized in vitro an M13mp3SuIII heteroduplex DNA that has a single mismatch at a predetermined site in the tRNA gene. Transformation of E. coli with the heteroduplex DNA yielded M13 recombinant phages carrying a mutant suppressor tRNA gene in which the sequence G-T-T-C, corresponding to the universal G-T-pseudouracil-C sequence in E. coli tRNAs, is changed to G-A-T-C. The mutant DNA has been characterized by restriction mapping and by sequence analysis. In contrast to results with the wild-type suppressor tRNA gene, cells transformed with recombinant plasmids carrying the mutant tRNA gene are phenotypically Su-. Thus, the single nucleotide change introduced has inactivated the function of the tRNA gene. By using E. coli minicells for studying the expression in vivo of cloned tRNA genes, we have found that cells transformed with recombinant plasmids carrying the mutant tRNA gene contain very little, if any, mature mutant suppressor tRNA. In contrast, the predominant low molecular weight RNA in cells transformed with recombinant plasmids carrying the wild-type suppressor tRNA gene is the mature tyrosine suppressor tRNA. Thus, while our results imply an important role for the G-T-pseudouracil-C sequence common to all E. coli tRNAs, whether this sequence is essential for tRNA biosynthesis, tRNA stability in vivo, or tRNA function remains to be determined. The procedures used to generate the mutant should be of general application toward site-specific mutagenesis on cloned DNAs, including regions that possess high degrees of secondary structure. In addition, the frequency of mutants among the progeny is high enough to enable one to identify and isolate site-specific mutants on any cloned DNA without requiring phenotypic selection.
    Proceedings of the National Academy of Sciences 08/1981; 78(8):4753-7. · 9.81 Impact Factor
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    ABSTRACT: Several DNA fragments carrying tRNA genes have been cloned from EcoRI endonuclease digests of Escherichia coli DNA. Using cloned DNA, the sequence of the region around the distal gene for tRNA1Asp (F(or G)) in the E. coli ribosomal RNA operon [rrnF(or G)] has been determined. In the distal portion of rrnF(or G), the genes for 23S, 5S rRNA and tRNA1Asp (F(or G)) are located in that order and separated by intergenic spacers of 93 and 52 base pairs, respectively. A possible hairpin structure, with its center between the 22nd and 23rd base pair downstream from the 3'-end of the tRNA1Asp(F(or G)) gene, followed by a sequence of eight thymidine residues was identified as the transcription termination signal for rrnF(or G). The termination is rho-independent, at least in vitro, and occurs within the region of the contiguous thymidine residues. A possible promoter for a protein gene is present about 50 base pairs downstream from the rrnF(or G) terminator.
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