Functional conservation of tRNase ZL among Saccharomyces cerevisiae, Schizosaccharomyces pombe and humans

2009 ◽  
Vol 422 (3) ◽  
pp. 483-492 ◽  
Author(s):  
Zhen Zhao ◽  
Wenchen Su ◽  
Sheng Yuan ◽  
Ying Huang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Schizosaccharomyces Pombe ◽  
Cancer Susceptibility ◽  
Short Form ◽  
Susceptibility Gene ◽  
Temperature Sensitive ◽  
Functional Conservation ◽  
Trnase Z

Although tRNase Z from various organisms was shown to process nuclear tRNA 3′ ends in vitro, only a very limited number of studies have reported its in vivo biological functions. tRNase Z is present in a short form, tRNase ZS, and a long form, tRNase ZL. Unlike Saccharomyces cerevisiae, which contains one tRNase ZL gene (scTRZ1) and humans, which contain one tRNase ZL encoded by the prostate-cancer susceptibility gene ELAC2 and one tRNase ZS, Schizosaccharomyces pombe contains two tRNase ZL genes, designated sptrz1+ and sptrz2+. We report that both sptrz1+ and sptrz2+ are essential for growth. Moreover, sptrz1+ is required for cell viability in the absence of Sla1p, which is thought to be required for endonuclease-mediated maturation of pre-tRNA 3′ ends in yeast. Both scTRZ1 and ELAC2 can complement a temperature-sensitive allele of sptrz1+, sptrz1–1, but not the sptrz1 null mutant, indicating that despite exhibiting species specificity, tRNase ZLs are functionally conserved among S. cerevisiae, S. pombe and humans. Overexpression of sptrz1+, scTRZ1 and ELAC2 can increase suppression of the UGA nonsense mutation ade6–704 through facilitating 3′ end processing of the defective suppressor tRNA that mediates suppression. Our findings reveal that 3′ end processing is a limiting step for defective tRNA maturation and demonstrate that overexpression of sptrz1+, scTRZ1 and ELAC2 can promote defective tRNA 3′ processing in vivo. Our results also support the notion that yeast tRNase ZL is absolutely required for 3′ end processing of at least a few pre-tRNAs even in the absence of Sla1p.

scholarly journals Partitioning of the Nuclear and Mitochondrial tRNA 3′-End Processing Activities between Two different Proteins in Schizosaccharomyces pombe

2013 ◽  
Vol 288 (38) ◽  
pp. 27415-27422 ◽  
Author(s):  
Xiaojie Zhang ◽  
Qiaoqiao Zhao ◽  
Ying Huang
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Short Form ◽  
Temperature Sensitive ◽  
Mitochondrial Trna ◽  
Gene Encoding ◽  
Protein Levels ◽  
Long Form ◽  
Trnase Z ◽  
Target Effects

tRNase Z is an essential endonuclease responsible for tRNA 3′-end maturation. tRNase Z exists in a short form (tRNase ZS) and a long form (tRNase ZL). Prokaryotes have only tRNase ZS, whereas eukaryotes can have both forms of tRNase Z. Most eukaryotes characterized thus far, including Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and humans, contain only one tRNase ZL gene encoding both nuclear and mitochondrial forms of tRNase ZL. In contrast, Schizosaccharomyces pombe contains two essential tRNase ZL genes (trz1 and trz2) encoding two tRNase ZL proteins, which are targeted to the nucleus and mitochondria, respectively. Trz1 protein levels are notably higher than Trz2 protein levels. Here, using temperature-sensitive mutants of trz1 and trz2, we provide in vivo evidence that trz1 and trz2 are involved in nuclear and mitochondrial tRNA 3′-end processing, respectively. In addition, trz2 is also involved in generation of the 5′-ends of other mitochondrial RNAs, whose 5′-ends coincide with the 3′-end of tRNA. Thus, our results provide a rare example showing partitioning of the nuclear and mitochondrial tRNase ZL activities between two different proteins in S. pombe. The evolution of two tRNase ZL genes and their differential expression in fission yeast may avoid toxic off-target effects.

Functional interaction between p21rap1A and components of the budding pathway in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (9) ◽  
pp. 4084-4092
Author(s):  
P C McCabe ◽  
H Haubruck ◽  
P Polakis ◽  
F McCormick ◽  
M A Innis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mammalian Cells ◽  
Bound States ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Amino Terminal ◽  
Loop Region

The rap1A gene encodes a 21-kDa, ras-related GTP-binding protein (p21rap1A) of unknown function. A close structural homolog of p21rap1A (65% identity in the amino-terminal two-thirds) is the RSR1 gene product (Rsr1p) of Saccharomyces cerevisiae. Although Rsr1p is not essential for growth, its presence is required for nonrandom selection of bud sites. To assess the similarity of these proteins at the functional level, wild-type and mutant forms of p21rap1A were tested for complementation of activities known to be fulfilled by Rsr1p. Expression of p21rap1A, like multicopy expression of RSR1, suppressed the conditional lethality of a temperature-sensitive cdc24 mutation. Point mutations predicted to affect the localization of p21rap1A or its ability to cycle between GDP and GTP-bound states disrupted suppression of cdc24ts, while other mutations in the 61-65 loop region improved suppression. Expression of p21rap1A could not, however, suppress the random budding phenotype of rsr1 cells. p21rap1A also apparently interfered with the normal activity of Rsrlp, causing random budding in diploid wild-type cells, suggesting an inability of p21rap1A to interact appropriately with Rsr1p regulatory proteins. Consistent with this hypothesis, we found an Rsr1p-specific GTPase-activating protein (GAP) activity in yeast membranes which was not active toward p21rap1A, indicating that p21rap1A may be predominantly GTP bound in yeast cells. Coexpression of human Rap1-specific GAP suppressed the random budding due to expression of p21rap1A or its derivatives, including Rap1AVal-12. Although Rap1-specific GAP stimulated the GTPase of Rsr1p in vitro, it did not dominantly interfere with Rsr1p function in vivo. A chimera consisting of Rap1A1-165::Rsr1p166-272 did not exhibit normal Rsr1p function in the budding pathway. These results indicated that p21rap1A and Rsr1p share at least partial functional homology, which may have implications for p21rap1A function in mammalian cells.

scholarly journals Translation initiation factor 4A from Saccharomyces cerevisiae: analysis of residues conserved in the D-E-A-D family of RNA helicases.

1991 ◽  
Vol 11 (7) ◽  
pp. 3463-3471 ◽  
Author(s):  
S R Schmid ◽  
P Linder
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Clear Correlation ◽  
Temperature Sensitive ◽  
Rna Helicases ◽  
Initiation Of Translation

The eukaryotic translation initiation factor 4A (eIF-4A) possesses an in vitro helicase activity that allows the unwinding of double-stranded RNA. This activity is dependent on ATP hydrolysis and the presence of another translation initiation factor, eIF-4B. These two initiation factors are thought to unwind mRNA secondary structures in preparation for ribosome binding and initiation of translation. To further characterize the function of eIF-4A in cellular translation and its interaction with other elements of the translation machinery, we have isolated mutations in the TIF1 and TIF2 genes encoding eIF-4A in Saccharomyces cerevisiae. We show that three highly conserved domains of the D-E-A-D protein family, encoding eIF-4A and other RNA helicases, are essential for protein function. Only in rare cases could we make a conservative substitution without affecting cell growth. The mutants show a clear correlation between their growth and in vivo translation rates. One mutation that results in a temperature-sensitive phenotype reveals an immediate decrease in translation activity following a shift to the nonpermissive temperature. These in vivo results confirm previous in vitro data demonstrating an absolute dependence of translation on the TIF1 and TIF2 gene products.

Identification of Schizosaccharomyces pombe transcription factor PGA4, which binds cooperatively to Saccharomyces cerevisiae GAL4-binding sites

1990 ◽  
Vol 10 (4) ◽  
pp. 1432-1438
Author(s):  
D M Ruden
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Schizosaccharomyces Pombe ◽  
Binding Sites ◽  
Transcription Activator ◽  
Integral Number ◽  
Dna Binding Site ◽  
Adh1 Gene

When the DNA-binding site for the Saccharomyces cerevisiae transcription activator GAL4 is placed upstream of the Schizosaccharomyces pombe ADH1 TATA box, transcription of the ADH1 gene is activated in S. pombe in vivo by an endogenous transcription factor. In vitro studies show that this S. pombe protein, PGA4, binds specifically to DNA containing a GAL4 site and that when two GAL4 sites are present, this protein binds cooperatively. Cooperating binding of PGA4 to DNA is favored if the GAL4 sites are separated by an integral number of turns of the DNA helix.

DNA damage hypersensitivity in cells lacking BRCA2: a review of in vitro and in vivo data

2005 ◽  
Vol 33 (4) ◽  
pp. 715-717 ◽  
Author(s):  
T. Hay ◽  
A.R. Clarke
Keyword(s):  
Cancer Susceptibility ◽  
Susceptibility Gene ◽  
Short Review ◽  
Breast Cancer Susceptibility ◽  
Breast Cancer Susceptibility Gene ◽  
Functional Protein ◽  
Increased Sensitivity ◽  
Cancer Susceptibility Gene

Since the discovery of the tumour suppressor BRCA2 (encoded by breast-cancer susceptibility gene 2), cells lacking the fully functional protein have consistently been found to show increased sensitivity to a variety of DNA-damaging agents, particularly those that cross-link DNA. In this short review, we will bring together these findings and discuss them in the light of our recent in vivo data in the mouse small intestine, which suggests that deletion of cells lacking Brca2 is necessary to avoid the development of potentially tumorigenic clones in this tissue, a system that may be less effective in the mammary glands of humans with germline mutations in BRCA2.

scholarly journals p62cdc23 of Saccharomyces cerevisiae: a nuclear tetratricopeptide repeat protein with two mutable domains.

1993 ◽  
Vol 13 (2) ◽  
pp. 1212-1221 ◽  
Author(s):  
R S Sikorski ◽  
W A Michaud ◽  
P Hieter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle Progression ◽  
Single Amino Acid ◽  
Temperature Sensitive ◽  
Cycle Progression ◽  
Tetratricopeptide Repeats ◽  
Tetratricopeptide Repeat Protein ◽  
Cdc Genes

CDC23 is required in Saccharomyces cerevisiae for cell cycle progression through the G2/M transition. The CDC23 gene product contains tandem, imperfect repeats, termed tetratricopeptide repeats, (TPR) units common to a protein family that includes several other nuclear division CDC genes. In this report we have used mutagenesis to probe the functional significance of the TPR units within CDC23. Analysis of truncated derivatives indicates that the TPR block of CDC23 is necessary for the function or stability of the polypeptide. In-frame deletion of a single TPR unit within the repeat block proved sufficient to inactivate CDC23 in vivo, though this allele could rescue the temperature-sensitive defect of a cdc23 point mutant by intragenic complementation. By both in vitro and in vivo mutagenesis techniques, 17 thermolabile cdc23 alleles were produced and examined. Fourteen alleles contained single amino acid changes that were found to cluster within two distinct mutable domains, one of which encompasses the most canonical TPR unit found in CDC23. In addition, we have characterized CDC23 as a 62-kDa protein (p62cdc23) that is localized to the yeast nucleus. Our mutagenesis results suggest that TPR blocks form an essential domain within members of the TPR family.

Translation initiation factor 4A from Saccharomyces cerevisiae: analysis of residues conserved in the D-E-A-D family of RNA helicases

1991 ◽  
Vol 11 (7) ◽  
pp. 3463-3471 ◽  
Author(s):  
S R Schmid ◽  
P Linder
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Clear Correlation ◽  
Temperature Sensitive ◽  
Rna Helicases ◽  
Initiation Of Translation

The eukaryotic translation initiation factor 4A (eIF-4A) possesses an in vitro helicase activity that allows the unwinding of double-stranded RNA. This activity is dependent on ATP hydrolysis and the presence of another translation initiation factor, eIF-4B. These two initiation factors are thought to unwind mRNA secondary structures in preparation for ribosome binding and initiation of translation. To further characterize the function of eIF-4A in cellular translation and its interaction with other elements of the translation machinery, we have isolated mutations in the TIF1 and TIF2 genes encoding eIF-4A in Saccharomyces cerevisiae. We show that three highly conserved domains of the D-E-A-D protein family, encoding eIF-4A and other RNA helicases, are essential for protein function. Only in rare cases could we make a conservative substitution without affecting cell growth. The mutants show a clear correlation between their growth and in vivo translation rates. One mutation that results in a temperature-sensitive phenotype reveals an immediate decrease in translation activity following a shift to the nonpermissive temperature. These in vivo results confirm previous in vitro data demonstrating an absolute dependence of translation on the TIF1 and TIF2 gene products.

scholarly journals A chicken beta-actin gene can complement a disruption of the Saccharomyces cerevisiae ACT1 gene.

1991 ◽  
Vol 11 (1) ◽  
pp. 213-217 ◽  
Author(s):  
R Karlsson ◽  
P Aspenström ◽  
A S Byström
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Slow Growth ◽  
Temperature Sensitive ◽  
Actin Gene ◽  
Expression Plasmid ◽  
Site Specific ◽  
Beta Actin ◽  
Engineering Study

Recently it was demonstrated that beta-actin can be produced in Saccharomyces cerevisiae by using the expression plasmid pY beta actin (R. Karlsson, Gene 68:249-258, 1988), and several site-specific mutants are now being produced in a protein engineering study. To establish a system with which recombinant actin mutants can be tested in vivo and thus enable a correlation to be made with functional effects observed in vitro, a yeast strain lacking endogenous yeast actin and expressing exclusively beta-actin was constructed. This strain is viable but has an altered morphology and a slow-growth phenotype and is temperature sensitive to the point of lethality at 37 degrees C.

scholarly journals Faithful chromosome transmission requires Spt4p, a putative regulator of chromatin structure in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (6) ◽  
pp. 2838-2847 ◽  
Author(s):  
M A Basrai ◽  
J Kingsbury ◽  
D Koshland ◽  
F Spencer ◽  
P Hieter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Instability ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Chromosome Fragment ◽  
Dna Mutations ◽  
Chromosome Transmission ◽  
Biochemical Assays

A chromosome transmission fidelity (ctf) mutant, s138, of Saccharomyces cerevisiae was identified by its centromere (CEN) transcriptional readthrough phenotype, suggesting perturbed kinetochore integrity in vivo. The gene complementing the s138 mutation was found to be identical to the S. cerevisiae SPT4 gene. The s138 mutation is a missense mutation in the second of four conserved cysteine residues positioned similarly to those of zinc finger proteins, and we henceforth refer to the mutation of spt4-138. Both spt4-138 and spt4 delta strains missegregate a chromosome fragment at the permissive temperature, are temperature sensitive for growth at 37 degrees C, and upon a shift to the nonpermissive temperature show an accumulation of large budded cells, each with a nucleus. Previous studies suggest that Spt4p functions in a complex with Spt5p and Spt6p, and we determined that spt6-140 also causes missegregation of a chromosome fragment. Double mutants carrying spt4 delta 2::HIS3 and kinetochore mutation ndc10-42 or ctf13-30 show a synthetic conditional phenotype. Both spt4-138 and spt4 delta strains exhibit synergistic chromosome instability in combination with CEN DNA mutations and show in vitro defects in microtubule binding to minichromosomes. These results indicate that Spt4p plays a role in chromosome segregation. The results of in vivo genetic interactions with mutations in kinetochore proteins and CEN DNA and of in vitro biochemical assays suggest that Spt4p is important for kinetochore function.

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