Identification of multiple RNases in Xenopus laevis oocytes and their possible role in tRNA processing.

Solari, Aldo; Deutscher, Murray P.

doi:10.1128/mcb.3.10.1711

Cited by 23 publications

(15 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Exonuclease action alone may suffice to remove the 3' trailing sequence of several pretRNAs, possibly inducing the pre-tRNA Asp generated by RNase P cleavage P1 in fig.2. Other workers have presented biochemical evidence that Volume 250, number 2 FEBS maturation of the 3' terminus of certain eukaryotic pre-tRNAs can proceed through endonucleolytic cleavage [14][15][16]. This study with extracts from the yeast rna82 mutant is the first time the genetic approach has been used to demonstrate such an endonucleolytic step.…”

Section: Resultsmentioning

confidence: 93%

Processing of transcripts of a dimeric tRNA gene in yeast uses the nuclease responsible for maturation of the 3′ termini upon 5 S and 37 S precursor rRNAs

Piper

Stråby

1989

FEBS Letters

View full text Add to dashboard Cite

The rna82 mutation of Saccharomyces cerevisiae inactivates an RNA processing activity responsible for maturation of 3'-terminal sequences upon 5 S and 37 S ribosomal RNA precursors. This study describes a difference in the processing of transcripts of an S. cerevisiae dimeric tRNA gene (tRNA^rLtRNA~p) in RNA polymerase III in vitro transcription extracts prepared from rna82 and wild-type cells. The mutant extract accumulated additional processing intermediates containing tRNAArg sequences as compared to the extract from wild-type cells. The structure of these intermediates revealed a defect in removal of the 10 nucleotides left 3' to the tRNA^rg sequence by the RNase P cleavage immediately 5' to tRNA ^~p. This is the first demonstration of a mutational defect affecting maturation of 3' sequences upon a eukaryotic tRNA precursor.tRNA precursor; Nuclease deficiency; Sequence maturation, Y-; (S. cerevisiae)

show abstract

Section: Resultsmentioning

confidence: 93%

Processing of transcripts of a dimeric tRNA gene in yeast uses the nuclease responsible for maturation of the 3′ termini upon 5 S and 37 S precursor rRNAs

Piper

Stråby

1989

FEBS Letters

View full text Add to dashboard Cite

show abstract

“…The best-documented pre-tRNA 3'-processing pathway in bacteria (4,8,39) involves initial endonuclease cleavage distal to the tRNA followed by 3'-5' exonuclease trimming back to the mature CCA terminus. By contrast, in many eukaryotes, a nuclear 3' endonuclease was shown to cleave pre-tRNAs immediately following nucleotide 73 (6,14,23,41). We demonstrate that a wheat embryo activity also cleaves yeast pre-tRNAPhe between C73 and C74, generating a 73-nt-long product, tRNAOH.…”

Section: Downloaded Frommentioning

confidence: 97%

“…Maturation of tRNA precursors requires at least two nucleolytic events: cleavage of the 5' leader segment by the endonuclease RNase P (11,26,35,44) and removal of the 3' trailer sequences by endo-or exonucleases (4,8,12,14,15,19,23,28,39,41,47). In addition, precursor tRNAs in eukaryotic nuclei and organelles do not contain the sequence -C-C-Acorresponding to the 3' terminus of mature tRNA (reviewed in references 10 and 11).…”

mentioning

confidence: 99%

Cleavage specificity of chloroplast and nuclear tRNA 3'-processing nucleases.

Oommen

Gegenheimer

1992

Mol. Cell. Biol.

View full text Add to dashboard Cite

tRNAs in eukaryotic nuclei and organelles are synthesized as precursors lacking the 3'-terminal CCA sequence and possessing 5' (leader) and 3' (trailer) extensions. Nucleolytic cleavage of the 3' trailer and addition of CCA are therefore required for formation of functional tRNA 3' termini. Many chloroplast tRNA genes encode a C at position 74 which is not removed during processing but which can be incorporated as the first base of the CCAOH terminus. Sequences downstream of nucleotide 74, however, are always removed.Synthetic yeast pre-tRNA"te substrates containing the complete CCA7476 sequence were processed with crude or partially purified chloroplast enzyme fractions. The 3'-extended substrates (tRNA-CCA-trailer) were cleaved exclusively between nucleotides 74 and 75 to give tRNA-COH, whereas a 3'-mature transcript (tRNA-CCAoH) was not cleaved at all. A 5'-, 3'-extended chloroplast tRNA-CAG-trailer was also processed entirely to tRNA-COH. Furthermore, a 5'-mature, 3'-extended yeast pre-tRNAPhe derivative, tRNA-ACAtrailer, in which C74 was replaced by A, was cleaved precisely after A74. In contrast, we found that a partially purified enzyme fraction (a nuclear/cytoplasmic activity) from wheat embryo cleaved the 3'-extended yeast tRNAPhe precursors between nucleotides 73 and 74 to give tRNAOH. This specificity is consistent with that of all previously characterized nuclear enzyme preparations. We conclude that (i) chloroplast tRNA 3'-processing endonuclease cleaves after nucleotide 74 regardless of the nature of the surrounding sequences; (ii) this specificity differs from that of the plant nuclear/cytoplasmic processing nuclease, which cleaves after base 73; and (iii) since 3'-mature tRNA is not a substrate for either activity, these 3' nucleases must require substrates possessing a 3'-terminal extension that extends past nucleotide 76. This substrate specificity may prevent mature tRNA from counterproductive cleavage by the 3' processing system.

show abstract

“…The majority of nuclear and chloroplast 3Ј processing enzymes have been found to be endonucleases cleaving at the tRNA 3Ј end (5-10), although prokaryotic-like 3Ј maturation with exonucleases being involved has also been observed (11)(12)(13)(14). At present the general consensus appears to attribute a multistep processing pathway to prokaryotes, whereas in eukaryotes single-step reactions predominate.…”

Section: Introductionmentioning

confidence: 99%

5′ end maturation and RNA editing have to precede tRNA 3′ processing in plant mitochondria

Kunzmann

Brennicke

Marchfelder

1998

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We report the characterization and partial purification of potato mitochondrial RNase Z, an endonuclease that generates mature tRNA 3 ends. The enzyme consists of one (or more) protein(s) without RNA subunits. Products of the processing reaction are tRNA molecules with 3 terminal hydroxyl groups and 3 trailers with 5 terminal phosphates. The main processing sites are located immediately 3 to the discriminator and one nucleotide further downstream. This endonucleolytic processing at and close to the tRNA 3 end in potato mitochondria suggests a higher similarity to the eukaryotic than to the prokaryotic tRNA 3 processing pathway. Partial purification and separation of RNase Z from the 5 processing activity RNase P allowed us to determine biochemical characteristics of the enzyme. The activity is stable over broad pH and temperature ranges, with peak activity at pH 8 and 30°C. Optimal concentrations for MgCl 2 and KCl are 5 mM and 30 mM, respectively. The potato mitochondrial RNase Z accepts only tRNA precursors with mature 5 ends. The precursor for tRNA Phe requires RNA editing for efficient processing by RNase Z.In all genetic systems, mature functional tRNAs are generated by several processing reactions that include the removal of cotranscribed 5Ј and 3Ј extensions. Processing at the tRNA 5Ј end is catalyzed by the ubiquitous endoribonuclease RNase P (1, 2) well characterized in prokaryotes (3). Although the reaction at the tRNA 5Ј end is alike in bacteria, archaeas, and eukaryotes (nuclei and organelles), tRNA 3Ј end maturation seems to be more variable.In Escherichia coli an endonucleolytic cleavage several nucleotides downstream of the tRNA is followed by exonucleolytic removal of some of the residual nucleotides. Only after RNase P has then matured the 5Ј terminus of the tRNA are the remaining extra 3Ј residues removed. This step yields the mature tRNA molecule because the terminal CCA OH sequence is genomically encoded in E. coli (for review, see ref. 4).The majority of nuclear and chloroplast 3Ј processing enzymes have been found to be endonucleases cleaving at the tRNA 3Ј end (5-10), although prokaryotic-like 3Ј maturation with exonucleases being involved has also been observed (11)(12)(13)(14). At present the general consensus appears to attribute a multistep processing pathway to prokaryotes, whereas in eukaryotes single-step reactions predominate.Mitochondria may have retained a prokaryotic-like processing system because they are thought to be of prokaryotic origin according to the endosymbiont theory (15). On the other hand, they may have adapted the host nuclear enzymes for processing, precedence having been found with tRNA modifying enzymes in yeast mitochondria (16) and plant mitochondria (17). To clarify the nature and origin of the plant mitochondrial tRNA processing machinery, the enzymes involved have to be investigated and characterized in detail.A special feature of mitochondrial tRNA maturation in plant cells is the involvement of RNA editing (18)(19)(20)). Herein we demonstrate that...

show abstract

Identification of multiple RNases in Xenopus laevis oocytes and their possible role in tRNA processing.

Cited by 23 publications

References 27 publications

Processing of transcripts of a dimeric tRNA gene in yeast uses the nuclease responsible for maturation of the 3′ termini upon 5 S and 37 S precursor rRNAs

Processing of transcripts of a dimeric tRNA gene in yeast uses the nuclease responsible for maturation of the 3′ termini upon 5 S and 37 S precursor rRNAs

Cleavage specificity of chloroplast and nuclear tRNA 3'-processing nucleases.

5′ end maturation and RNA editing have to precede tRNA 3′ processing in plant mitochondria

Contact Info

Product

Resources

About