Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ammonium sulfate fractionation of a Saccharomyces cerevisiae whole-cell extract yielded a preparation which carried out correct and efficient endonucleolytic cleavage and polyadenylation of yeast precursor mRNA substrates corresponding to a variety of yeast genes. These included CYC1 (iso-1-cytochrome c), HIS4 (histidine biosynthesis), GAL7 (galactose-1-phosphate uridyltransferase), H2B2 (histone H2B2), PRT2 (a protein of unknown function), and CBP1 (cytochrome b mRNA processing). The reaction processed these pre-mRNAs with varying efficiencies, with cleavage and polyadenylation exceeding 70% in some cases. In each case, the poly(A) tail corresponded to the addition of approximately 60 adenosine residues, which agrees with the usual length of poly(A) tails formed in vivo. Addition of cordycepin triphosphate or substitution of CTP for ATP in these reactions inhibited polyadenylation but not endonucleolytic cleavage and resulted in accumulation of the cleaved RNA product. Although this system readily generated yeast mRNA 3' ends, no processing occurred on a human alpha-globin pre-mRNA containing the highly conserved AAUAAA polyadenylation signal of higher eucaryotes. This sequence and adjacent signals used in mammalian systems are thus not sufficient to direct mRNA 3' end formation in yeast. Despite the lack of a highly conserved nucleotide sequence signal, the same purified fraction processed the 3' ends of a variety of unrelated yeast pre-mRNAs, suggesting that endonuclease cleavage and polyadenylation may produce the mature 3' ends of all mRNAs in S. cerevisiae.
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PMID:RNA processing in vitro produces mature 3' ends of a variety of Saccharomyces cerevisiae mRNAs. 216 May 81

The product of the Rous sarcoma virus (RSV) gag gene, Pr76gag, is a polyprotein precursor which is cleaved by the viral protease to yield the major structural proteins of the virion during particle assembly in avian host cells. We have recently shown that myristylated forms of the RSV Gag protein can induce particle formation with very high efficiency when expressed in mammalian cells (J. W. Wills, R. C. Craven, and J. A. Achacoso, J. Virol. 63:4331-4343, 1989). We made use of this mammalian system to examine the abilities of foreign antigens to be incorporated into particles when fused directly to the myristylated Gag protein. Our initial experiments showed that removal of various portions of the viral protease located at the carboxy terminus of the RSV Gag protein did not disrupt particle formation. We therefore chose this region for coupling of iso-1-cytochrome c from Saccharomyces cerevisiae to Gag. This was accomplished by constructing an in-frame fusion of the CYC1 and gag coding sequences at a common restriction endonuclease site. Expression of the chimeric gene resulted in synthesis of the Gag-cytochrome fusion protein and its release into the cell culture medium. The chimeric particles were readily purified by simple centrifugation, and transmission electron microscopy of cells that produced them revealed a morphology similar to that of immature type C retrovirions.
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PMID:Incorporation of chimeric gag protein into retroviral particles. 216 12

In whole cell extracts of Saccharomyces cerevisiae, incubation of precursor mRNA transcripts encoding the sequences essential in vivo for forming the 3' end of the iso-1-cytochrome c mRNA (CYC1) revealed an endonuclease activity with the characteristics required for producing the mature mRNA 3' end. The observed cleavage in vitro is (i) accurate, occurring at or near the polyadenylation site of CYC1 RNA, (ii) 30 to 50 percent efficient, (iii) adenosine triphosphate dependent, (iv) specific for the 3' ends of at least two yeast pre-mRNA's, and (v) absent with related pre-mRNA's carrying mutations that abolish correct 3' end formation in vivo. In addition, a second activity in the extract polyadenylates the product under appropriate conditions. Thus, the mature 3' ends of yeast mRNA's may be generated by endonucleolytic cleavage and polyadenylation rather than by transcription termination.
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PMID:RNA processing generates the mature 3' end of yeast CYC1 messenger RNA in vitro. 284 17

We have constructed a plasmid that selectively integrates adjacent to the CYC1 locus, which determines iso-1-cytochrome c in the yeast Saccharomyces cerevisiae. Different CYC1 alleles can be conveniently recovered by digestion of total DNA from transformed strains with BgI II, a restriction endonuclease that does not cut the vector or the CYC1 gene, followed by transformation of Escherichia coli, selecting the ampicillin resistance gene carried on the original vector. This procedure was used to clone the cyc1-362 gene, which contains an alteration in front of the AUG initiation codon. The cyc1-362 mutational causes a deficiency of the iso-1-cytochrome c protein but still allows transcription of the iso-1-cytochrome c mRNA. DNA sequence analysis showed that the cyc1-362 mutation consisted of two single-base-pair substitutions, producing an A leads to G change 18 nucleotides and a G leads to A change 30 nucleotides in front of the AUG initiation codon in the mRNA. The A leads to G change at position -18 resulted in the creation of an AUG triplet, which is proximal to the normal initiation site and out of phase with the normal reading frame. The deficiency of iso-1-cytochrome c is most simply explained by assuming that translation initiates at the more proximal abnormal AUG site but not at the normal AUG site.
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PMID:DNA sequence of a mutation in the leader region of the yeast iso-1-cytochrome c mRNA. 626 5

In Saccharomyces cerevisiae, snoRNAs are encoded by independent genes and within introns. Despite this heterogenous organization, snoRNA biosynthesis relies on a common theme: entry sites for 5'-3' and 3'-5' exonucleases are created on precursor molecules allowing the release of mature snoRNAs. In independently transcribed snoRNAs, such entry sites are often produced by the Rnt1p endonuclease. In many cases, cleavage sites are absent in the 3' portion of the pre-snoRNAs, suggesting that processing starts from the 3' end of the primary transcript. Here we show that cleavage/polyadenylation sites driving efficient polyadenylation, such as CYC1, prevent production of mature and functional snoRNPs. With these sites, snoRNA accumulation is restored only if polyadenylation activity is inhibited. Analysis of sequences downstream of snoRNA-coding units and the use of strains carrying mutations in RNA polymerase II (polII) cleavage/polyadenylation activities allowed us to establish that formation of snoRNA mature 3' ends requires only the cleavage activity of the polII 3'-processing machinery. These data indicate that, in vivo, uncoupling of cleavage and polyadenylation is necessary for an essential cellular biosynthesis.
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PMID:Yeast snoRNA accumulation relies on a cleavage-dependent/polyadenylation-independent 3'-processing apparatus. 1108 Jan 67