Biomaterial Database

Pre-tRNA 3'-processing in Saccharomyces cerevisiae. Purification and characterization of exo- and endoribonucleases. 1996

A Papadimitriou, and H J Gross

Institut für Biochemie, Bayerische Julius-Maximilians-Universität, Biozentrum, Würzburg, Germany.

We investigated ribonucleases from Saccharomyces cerevisiae which are active in pre-tRNA 3'-processing in vitro. Two pre-tRNA 3'-exonucleases with molecular masses of 33 and 60 kDa, two pre-tRNA 3'-endonucleases with molecular masses of 45 kDa/60 kDa and 55 kDa and 70-kDa 3'-pre-tRNase were purified from yeast whole cell extracts by several successive chromatographic purification steps. The purified exonucleases are non-processive 3'-exonucleases that catalyze the exonucleolytic processing of 3'-trailer sequences of pre-tRNAs to produce mature tRNAs. The 45-kDa/60-kDa 3'-endonuclease is tRNA-specific and catalyzes the processing of pre-tRNAs in a single endonucleolytic step. Two isoenzymes of this activity (p45 and p60) were identified by chromatography. The second endonuclease, p55, is dependent on monovalent ions and cleaves about three nucleotides downstream the mature 3'-end. All of the purified 3'-pre-tRNases accept homologous as well as heterologous pre-tRNA substrates. Pre-tRNAs carrying a 5'-leader are processed with almost the same efficiency as those lacking this 5'-leader. Mature tRNAs carrying the CCA 3'-sequence and tRNA pseudogene products carrying mutations in the mature domain are processed by the 3'-exonucleases, not by the 3'-endonucleases. The specific endonuclease p45/p60 discriminates between UUUOH as a 3'-flank, which is cleaved, and the CCA 3'-end of mature tRNAs, which is not cleaved. This study suggests that several 3'-pre-tRNases are active on tRNA precursors in vitro and might therefore in pre-tRNA 3'-processing in yeast, partly in a cooperative manner.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009694	Nucleic Acid Precursors	Use for nucleic acid precursors in general or for which there is no specific heading.	Acid Precursors, Nucleic,Precursors, Nucleic Acid
D011544	Pseudogenes	Genes bearing close resemblance to known genes at different loci, but rendered non-functional by additions or deletions in structure that prevent normal transcription or translation. When lacking introns and containing a poly-A segment near the downstream end (as a result of reverse copying from processed nuclear RNA into double-stranded DNA), they are called processed genes.	Genes, Processed,beta-Tubulin Pseudogene,Gene, Processed,Processed Gene,Processed Genes,Pseudogene,Pseudogene, beta-Tubulin,Pseudogenes, beta-Tubulin,beta Tubulin Pseudogene,beta-Tubulin Pseudogenes
D004722	Endoribonucleases	A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.	Endoribonuclease
D005095	Exoribonucleases	A family of enzymes that catalyze the exonucleolytic cleavage of RNA. It includes EC 3.1.13.-, EC 3.1.14.-, EC 3.1.15.-, and EC 3.1.16.-. EC 3.1.-	Exoribonuclease
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D012323	RNA Processing, Post-Transcriptional	Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.	Post-Transcriptional RNA Modification,RNA Processing,Post-Transcriptional RNA Processing,Posttranscriptional RNA Processing,RNA Processing, Post Transcriptional,RNA Processing, Posttranscriptional,Modification, Post-Transcriptional RNA,Modifications, Post-Transcriptional RNA,Post Transcriptional RNA Modification,Post Transcriptional RNA Processing,Post-Transcriptional RNA Modifications,Processing, Posttranscriptional RNA,Processing, RNA,RNA Modification, Post-Transcriptional,RNA Modifications, Post-Transcriptional
D012343	RNA, Transfer	The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.	Suppressor Transfer RNA,Transfer RNA,tRNA,RNA, Transfer, Suppressor,Transfer RNA, Suppressor,RNA, Suppressor Transfer