Sequencing of a 35·71 kb DNA segment on the right arm of yeast chromosome XV reveals regions of similarity to chromosomes I and XIII

Pearson, Bruce M.; Hernando, Yolanda; Payne, John W.; Wolf, Siegmund S.; Kalogeropoulos, Angelos; Schweizer, Michael

doi:10.1002/(sici)1097-0061(199609)12:10b<1021::aid-yea981>3.0.co;2-7

Cited by 7 publications

(3 citation statements)

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“…A search of the yeast genomic database identified another ORF (accession no. X90565) (36), which is located on chromosome XV and encodes a polypeptide of 511 amino acids, that we designated NOP58. Nop56p and Nop58p are highly homologous (45% identical and 63% similar) over their entire sequences (Fig.…”

Section: Resultsmentioning

confidence: 99%

Nucleolar KKE/D Repeat Proteins Nop56P and Nop58P Interact with Nop1p and Are Required for Ribosome Biogenesis

Gautier

Bergès

Tollervey

et al. 1997

Molecular and Cellular Biology

259

226

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Different point mutations in the nucleolar protein fibrillarin (Nop1p in Saccharomyces cerevisiae) can inhibit different steps in ribosome synthesis. A screen for mutations that are synthetically lethal (sl) with the nop1-5 allele, which inhibits pre-rRNA processing, identified NOP56. An independent sl mutation screen with nop1-3, which inhibits pre-rRNA methylation, identified a mutation in NOP58. Strikingly, Nop56p and Nop58p are highly homologous (45% identity). Both proteins were found to be essential and localized to the nucleolus. A temperature-sensitive lethal mutant allele, nop56-2, inhibited many steps in pre-rRNA processing, particularly on the pathway of 25S/5.8S rRNA synthesis, and led to defects in 60S subunit assembly. Epitope-tagged constructs show that both Nop56p and Nop58p are associated with Nop1p in complexes, Nop56p and Nop1p exhibiting a stoichiometric association. These physical interactions presumably underlie the observed sl phenotypes. Well-conserved homologs are present in a range of organisms, including humans (52% identity between human hNop56p and yeast Nop56p), suggesting that these complexes have been conserved in evolution.Most steps of ribosome biogenesis occur in the nucleolus, a specialized subnuclear structure (for reviews, see references 14, 34, 39, 45, and 53). In eukaryotes including Saccharomyces cerevisiae and humans, a large precursor rRNA transcript (prerRNA) is processed into the mature 18S, 5.8S, and 25S/28S rRNAs. During transcription and processing, these rRNAs associate with approximately 80 ribosomal proteins and with the 5S rRNA. In addition, the mature rRNA regions of the prerRNA undergo extensive covalent nucleotide modification, mainly base modification of uridine to pseudouridine and methylation of the ribose 2Ј-hydroxyl (2Ј-O methylation) (reviewed in reference 27). The large number of concerted reactions occurring during rRNA processing and ribosome assembly has made it difficult to analyze single steps in ribosome synthesis. Over recent years, the analysis of yeast mutants defective in ribosome biogenesis has proved to be a powerful approach (reviewed in reference 51), particularly when combined with in vitro analyses using purified components (8,26,30). Despite this progress, our understanding of the detailed mechanisms of eukaryotic rRNA processing remains poor.The small nucleolar RNAs (snoRNAs) play important roles in the covalent processing of the pre-rRNAs (reviewed in references 2, 28, and 48). With the exception of RNase MRP, which is an endonuclease structurally related to RNase P, the very large numbers of snoRNAs present in eukaryotes can be divided into two groups based on conserved sequence and structural features (3, 12; reviewed in reference 48). Most of the box CϩD snoRNAs direct the site-specific 2Ј-O methylation of the pre-rRNA (19), while most of the box HϩACA snoRNAs select the sites of pseudouridine formation (6,11,33). In addition, a few members of each group of snoRNAs do not appear to select sites of pre-rRNA modification but are re...

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Section: Resultsmentioning

confidence: 99%

Nucleolar KKE/D Repeat Proteins Nop56P and Nop58P Interact with Nop1p and Are Required for Ribosome Biogenesis

Gautier

Bergès

Tollervey

et al. 1997

Molecular and Cellular Biology

259

226

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“…Saccharomyces has undergone a genome duplication sometime after it diverged from another Ascomycete, Kluyveromyces (Wolfe and Shields, 1997), and MYO2 and MYO4 lie in an unambiguously duplicated region ( Fig. 8 A) (Parle-McDermott et al, 1996;Pearson et al, 1996;Storms et al, 1997). In support of a recent duplication, the Myo2p and Myo4p tails are more similar to each other than to any other myosin V. Furthermore, phylogenetic analysis of motor domain sequences (Fig.…”

Section: The Myo2p and Myo4p Tail Sequences Reflect Their Divergent Fmentioning

confidence: 87%

The Cooh-Terminal Domain of Myo2p, a Yeast Myosin V, Has a Direct Role in Secretory Vesicle Targeting

Schott

Pruyne

et al. 1999

The Journal of Cell Biology

232

299

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MYO2 encodes a type V myosin heavy chain needed for the targeting of vacuoles and secretory vesicles to the growing bud of yeast. Here we describe new myo2 alleles containing conditional lethal mutations in the COOH-terminal tail domain. Within 5 min of shifting to the restrictive temperature, the polarized distribution of secretory vesicles is abolished without affecting the distribution of actin or the mutant Myo2p, showing that the tail has a direct role in vesicle targeting. We also show that the actin cable–dependent translocation of Myo2p to growth sites does not require secretory vesicle cargo. Although a fusion protein containing the Myo2p tail also concentrates at growth sites, this accumulation depends on the polarized delivery of secretory vesicles, implying that the Myo2p tail binds to secretory vesicles. Most of the new mutations alter a region of the Myo2p tail conserved with vertebrate myosin Vs but divergent from Myo4p, the myosin V involved in mRNA transport, and genetic data suggest that the tail interacts with Smy1p, a kinesin homologue, and Sec4p, a vesicle-associated Rab protein. The data support a model in which the Myo2p tail tethers secretory vesicles, and the motor transports them down polarized actin cables to the site of exocytosis.

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“…in Escherichia coli; see Ref. 19) and S. cerevisiae (20,21) have been cloned and sequenced. Mutant strains of S. cerevisiae auxotrophic for proline because of mutations in ␥-GK or ␥-GPR genes are known and provide a potential system for expression and analysis of human P5CS.…”

mentioning

confidence: 99%

Molecular Enzymology of Mammalian Δ1-Pyrroline-5-carboxylate Synthase

Lin

Obie

et al. 1999

Journal of Biological Chemistry

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⌬1 -Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP-and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to ⌬ 1 -pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp ؉711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the ␥-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in ␥-glutamyl kinase-and ␥-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a K i of ϳ0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.

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Sequencing of a 35·71 kb DNA segment on the right arm of yeast chromosome XV reveals regions of similarity to chromosomes I and XIII

Cited by 7 publications

References 50 publications

Nucleolar KKE/D Repeat Proteins Nop56P and Nop58P Interact with Nop1p and Are Required for Ribosome Biogenesis

Nucleolar KKE/D Repeat Proteins Nop56P and Nop58P Interact with Nop1p and Are Required for Ribosome Biogenesis

The Cooh-Terminal Domain of Myo2p, a Yeast Myosin V, Has a Direct Role in Secretory Vesicle Targeting

Molecular Enzymology of Mammalian Δ1-Pyrroline-5-carboxylate Synthase

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