The <i>Schizosaccharomyces pombe mra1 </i>gene, which is required for cell growth and mating, can suppress the mating inefficiency caused by a deficit in the Ras1 activity

Hakuno, Fumihiko; Hughes, David A.; Yamamoto, Masayuki

doi:10.1046/j.1365-2443.1996.27029.x

Cited by 7 publications

(8 citation statements)

References 55 publications

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“…A previous study of the fission yeast orthologue of Emg1, called Mra1, suggested that Mra1 might genetically interact with the Ras-signaling pathway, because overexpression of mra1 suppressed an allelic ras1 mutation that resulted in inefficient mating (Hakuno et al, 1996). Epistasis experiments, however, indicated that Mra1 suppression of the rasS40T allele was indirect.…”

Section: Discussionmentioning

confidence: 99%

“…A temperature-sensitive allele of EMG1 was created based on the observation that a point mutation in the conserved central region of the Schizosaccharomyces pombe mra1 (K213E) led to a protein of altered function (Hakuno et al, 1996). An oligonucleotide (5Ј-ATA-GACCTGGACCN(C,G,T) TCCGGCTTTGTTGATTGG-3Ј) in which the first two positions of the homologous amino acid (K109) in baker's yeast EMG1 were randomized and a primer corresponding to the promoter of EMG1, we amplified the 5Ј-end of the EMG1 gene with the use of error-prone PCR.…”

Section: Generation Of Conditional Alleles Of Emg1 and Nop14mentioning

confidence: 99%

“…The Emg1 protein sequence is highly conserved among eukaryotes with greatest homology in the central region ( Figure 1B). The S. pombe orthologue of EMG1 (Mra1) was previously recovered as a dosage suppressor of an effector domain mutant of ras1 (T40S) that led to inefficient mating (Hakuno et al, 1996). Disruption of the EMG1 gene revealed that it is essential in baker's yeast as is the mra1 gene in S. pombe ( Figure 1C).…”

Section: A Novel Stress-responsive Mrna Encodes An Essential Conservmentioning

confidence: 99%

“…Emg1 physically interacts with an essential nucleolar protein Nop14 that functions in the same genetic and biochemical pathway as Emg1. The orthologous EMG1 gene mraI from fission yeast was previously isolated as a dosage suppressor of a ras1 effector domain mutant (Hakuno et al, 1996); however, the function of Mra1 was not elucidated. Here we provide evidence that Emg1 and its interacting partner protein Nop14 are required for appropriate processing of the pre-18S rRNA and small ribosomal subunit assembly.…”

Section: Introductionmentioning

confidence: 99%

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Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis

Liu

Thiele

2001

MBoC

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Under stressful conditions organisms adjust the synthesis, processing, and trafficking of molecules to allow survival from and recovery after stress. In baker's yeast Saccharomyces cerevisiae, the cellular production of ribosomes is tightly matched with environmental conditions and nutrient availability through coordinate transcriptional regulation of genes involved in ribosome biogenesis. On the basis of stress-responsive gene expression and functional studies, we have identified a novel, evolutionarily conserved gene, EMG1, that has similar stress-responsive gene expression patterns as ribosomal protein genes and is required for the biogenesis of the 40S ribosomal subunit. The Emg1 protein is distributed throughout the cell; however, its nuclear localization depends on physical interaction with a newly characterized nucleolar protein, Nop14. Yeast depleted of Nop14 or harboring a temperature-sensitive allele of emg1 have selectively reduced levels of the 20S pre-rRNA and mature18S rRNA and diminished cellular levels of the 40S ribosomal subunit. Neither Emg1 nor Nop14 contain any characterized functional motifs; however, isolation and functional analyses of mammalian orthologues of Emg1 and Nop14 suggest that these proteins are functionally conserved among eukaryotes. We conclude that Emg1 and Nop14 are novel proteins whose interaction is required for the maturation of the 18S rRNA and for 40S ribosome production.

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Section: Discussionmentioning

confidence: 99%

Section: Generation Of Conditional Alleles Of Emg1 and Nop14mentioning

confidence: 99%

Section: A Novel Stress-responsive Mrna Encodes An Essential Conservmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis

Liu

Thiele

2001

MBoC

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“…Cells of the ras1 deletion mutant are short and fat, in addition to being sterile, suggesting that they are defective in the maintenance of cell morphology (Fukui et al, 1986). Two pathways have been established to function downstream of Ras1p, although evidence suggesting a third possible pathway exists (Hakuno et al, 1996). One of the two is a MAP kinase cascade that transmits the mating pheromone signal and regulates nuclear gene expression, which is essential for mating but not for the maintenance of cell morphology (Wang et al, 1991;Nielsen et al, 1992;Xu et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Fission Yeast Pob1p, Which Is Homologous to Budding Yeast Boi Proteins and Exhibits Subcellular Localization Close to Actin Patches, Is Essential for Cell Elongation and Separation

Toya

Iino

Yamamoto

1999

MBoC

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The fission yeast pob1 gene encodes a protein of 871 amino acids carrying an SH3 domain, a SAM domain, and a PH domain. Gene disruption and construction of a temperature-sensitive pob1 mutant indicated that pob1 is essential for cell growth. Loss of its function leads to quick cessation of cellular elongation. Pob1p is homologous to two functionally redundant Saccharomyces cerevisiae proteins, Boi1p and Boi2p, which are necessary for cell growth and relevant to bud formation. Overexpression of pob1 inhibits cell growth, causing the host cells to become round and swollen. In growing cells, Pob1p locates at cell tips during interphase and translocates near the division plane at cytokinesis. Thus, this protein exhibits intracellular dynamics similar to F-actin patches. However, Pob1p constitutes a layer, rather than patches, at growing cell tips. It generates two split discs flanking the septum at cytokinesis. The pob1-defective cells no longer elongate but swell gradually at the middle, eventually assuming a lemon-like morphology. Analysis using the pob1-ts allele revealed that Pob1p is also essential for cell separation. We speculate that Pob1p is located on growing plasma membrane, possibly through the function of actin patches, and may recruit proteins required for the synthesis of cell wall.

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ras1 and pat1 alleles interact to quantitatively and qualitatively alter conjugation in fission yeast

Mach¹,

Cheng²,

Albright³

1998

Current Genetics

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To identify novel components of ras1+ signalling in Schizosaccharomyces pombe, extragenic suppressors of the mating defect of ras1 effector mutants were isolated. A novel allele of pat1, pat1-e1, was isolated that increases the mating of ras1-D43E mutants to near wild-type levels but does not suppress the mating defect of ras1-I41M, ras1-Y37F, or ras1-Y45I mutants. This allele-specific suppression is not a characteristic of all pat1 alleles since pat1-3 and pat1-114 partially and equally suppress ras1-D43E and ras1-I41M mutants. Analysis of mating cultures showed that ras1-D43E and pat1-e1 interact to qualitatively alter the mating response. While pat1-e1 ras1-D43E cells were delayed in agglutination, cell-cycle delay, and mat1-Pm transcription, they induce mat1-Mc at the same time and mate more rapidly than other mating cultures. These results suggest that pheromone signalling, but not nutritional signalling, is delayed in pat1-e1 ras1-D43E cells. We hypothesize that this delay causes an elevated pheromone response and thus suppression of the mating defect of the ras1-D43E mutant by pat1-e1.

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The Schizosaccharomyces pombe mra1 gene, which is required for cell growth and mating, can suppress the mating inefficiency caused by a deficit in the Ras1 activity

Cited by 7 publications

References 55 publications

Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis

Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis

Fission Yeast Pob1p, Which Is Homologous to Budding Yeast Boi Proteins and Exhibits Subcellular Localization Close to Actin Patches, Is Essential for Cell Elongation and Separation

ras1 and pat1 alleles interact to quantitatively and qualitatively alter conjugation in fission yeast

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