RNase T2 Family: Enzymatic Properties, Functional Diversity, and Evolution of Ancient Ribonucleases

MacIntosh, Gustavo C.

doi:10.1007/978-3-642-21078-5_4

Cited by 48 publications

(72 citation statements)

References 146 publications

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“…Some of these enzymes are specially interesting: (1) polyporopepsin, which can be implicated in protein degradation, supplying nitrogen for fungal growth, (2) mannose-6-phosphatase, which has been shown to be involved in the extracellular dephosphorylation of enzymes in carbon-starved cultures [33] and ribonuclease T2, that can be excreted in response to phosphate starvation for phosphate scavenging from RNA [34], and (3) the peroxidase cpop21 (currently identified as DyP), which can be produced to oxidize more complex molecules to be used as energy/nutrient source. Interestingly, and although not included in the Top-10, a second DyP isoenzyme related to that of Marasmius scorodonius [35] was detected.…”

Section: Resultsmentioning

confidence: 99%

Differential proteomic analysis of the secretome of Irpex lacteus and other white-rot fungi during wheat straw pretreatment

Salvachúa

Martı́nez

Tien

et al. 2013

Biotechnol Biofuels

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BackgroundIdentifying new high-performance enzymes or enzyme complexes to enhance biomass degradation is the key for the development of cost-effective processes for ethanol production. Irpex lacteus is an efficient microorganism for wheat straw pretreatment, yielding easily hydrolysable products with high sugar content. Thus, this fungus was selected to investigate the enzymatic system involved in lignocellulose decay, and its secretome was compared to those from Phanerochaete chrysosporium and Pleurotus ostreatus which produced different degradation patterns when growing on wheat straw. Extracellular enzymes were analyzed through 2D-PAGE, nanoLC/MS-MS, and homology searches against public databases.ResultsIn wheat straw, I. lacteus secreted proteases, dye-decolorizing and manganese-oxidizing peroxidases, and H2O2 producing-enzymes but also a battery of cellulases and xylanases, excluding those implicated in cellulose and hemicellulose degradation to their monosaccharides, making these sugars poorly available for fungal consumption. In contrast, a significant increase of β-glucosidase production was observed when I. lacteus grew in liquid cultures. P. chrysosporium secreted more enzymes implicated in the total hydrolysis of the polysaccharides and P. ostreatus produced, in proportion, more oxidoreductases.ConclusionThe protein pattern secreted during I. lacteus growth in wheat straw plus the differences observed among the different secretomes, justify the fitness of I. lacteus for biopretreatment processes in 2G-ethanol production. Furthermore, all these data give insight into the biological degradation of lignocellulose and suggest new enzyme mixtures interesting for its efficient hydrolysis.

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Section: Resultsmentioning

confidence: 99%

Differential proteomic analysis of the secretome of Irpex lacteus and other white-rot fungi during wheat straw pretreatment

Salvachúa

Martı́nez

Tien

et al. 2013

Biotechnol Biofuels

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“…20,[58][59][60][61] RNS2 is one of 5 RNase T2 enzymes found in Arabidopsis and is the only class II RNase T2 constitutively expressed throughout the plant and throughout development. 60,62 RNase T2 proteins are targeted to organelles of the secretory pathway, including the endoplasmic reticulum, Golgi apparatus, vacuole, lysosome, and associated vesicles, or secreted from the cell.…”

Section: Discussionmentioning

confidence: 99%

“…60,62 RNase T2 proteins are targeted to organelles of the secretory pathway, including the endoplasmic reticulum, Golgi apparatus, vacuole, lysosome, and associated vesicles, or secreted from the cell. 20,59,63 RNS2 is localized to the endoplasmic reticulum and vacuole, 19 where it functions in degradation of rRNA (and possibly other types of RNA) after uptake into the vacuole either as free RNA or as intact ribosomes. This pathway is thus complementary to cytoplasmic RNA degradation pathways, in which different classes of ribonucleases and degradation machineries function.…”

Section: Discussionmentioning

confidence: 99%

“…18 The involvement of Arabidopsis RNS2 and zebrafish RNASET2 in housekeeping rRNA turnover is consistent with the hypothesis that the conservation of the RNase T2 family in all eukaryotes is due to a conserved housekeeping role performed by these enzymes. 20 In fact, RNase T2 enzymes have been shown to participate in rRNA degradation in conditions of nutritional stress in addition to the housekeeping role in plants and animals described above. For example, RNase T2 enzymes accumulate in the vacuoles of phosphatedeprived tomato cells in parallel with significant rRNA degradation; 2 Rny1, the only RNase T2 enzyme in yeast, is responsible for rRNA and bulk RNA degradation in response to starvation and oxidative stress which results in metabolic changes; 5,21,22 and mutations affecting Tetrahymena thermophila RNase T2 enzymes cause changes in the patterns of rRNA degradation observed under starvation, suggesting that these enzymes also participate in a ribophagy-like mechanism as a nutrient stress response.…”

Section: Introductionmentioning

confidence: 99%

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Evidence for autophagy-dependent pathways of rRNA turnover inArabidopsis

et al. 2015

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Ribosomes account for a majority of the cell's RNA and much of its protein and represent a significant investment of cellular resources. The turnover and degradation of ribosomes has been proposed to play a role in homeostasis and during stress conditions. Mechanisms for the turnover of rRNA and ribosomal proteins have not been fully elucidated. We show here that the RNS2 ribonuclease and autophagy participate in RNA turnover in Arabidopsis thaliana under normal growth conditions. An increase in autophagosome formation was seen in an rns2-2 mutant, and this increase was dependent on the core autophagy genes ATG9 and ATG5. Autophagosomes and autophagic bodies in rns2-2 mutants contain RNA and ribosomes, suggesting that autophagy is activated as an attempt to compensate for loss of rRNA degradation. Total RNA accumulates in rns2-2, atg9-4, atg5-1, rns2-2 atg9-4, and rns2-2 atg5-1 mutants, suggesting a parallel role for autophagy and RNS2 in RNA turnover. rRNA accumulates in the vacuole in rns2-2 mutants. Vacuolar accumulation of rRNA was blocked by disrupting autophagy via an rns2-2 atg5-1 double mutant but not by an rns2-2 atg9-4 double mutant, indicating that ATG5 and ATG9 function differently in this process. Our results suggest that autophagy and RNS2 are both involved in homeostatic degradation of rRNA in the vacuole.

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“…An RNase with complete specificity for adenosines has not been reported. While the RNases T2 and U2 have been shown to have a preference for adenosines, they have also been found to cleave after other nucleotides, and U2 cleavage is highly dependent on the adjacent nucleotides (Rogg and Staehelin 1972;Yasuda and Inoue 1982;Deshpande and Shankar 2002;MacIntosh 2011). In contrast, Pf Csx1 shows remarkable specificity for cleaving diverse RNA substrates at sites containing an adenosine in several sequence contexts (Fig.…”

Section: Discussionmentioning

confidence: 99%

The CRISPR-associated Csx1 protein of Pyrococcus furiosus is an adenosine-specific endoribonuclease

Sheppard

Glover

Terns

et al. 2015

RNA

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Prokaryotes are frequently exposed to potentially harmful invasive nucleic acids from phages, plasmids, and transposons. One method of defense is the CRISPR-Cas adaptive immune system. Diverse CRISPR-Cas systems form distinct ribonucleoprotein effector complexes that target and cleave invasive nucleic acids to provide immunity. The Type III-B Cmr effector complex has been found to target the RNA and DNA of the invader in the various bacterial and archaeal organisms where it has been characterized. Interestingly, the gene encoding the Csx1 protein is frequently located in close proximity to the Cmr1-6 genes in many genomes, implicating a role for Csx1 in Cmr function. However, evidence suggests that Csx1 is not a stably associated component of the Cmr effector complex, but is necessary for DNA silencing by the Cmr system in Sulfolobus islandicus. To investigate the function of the Csx1 protein, we characterized the activity of recombinant Pyrococcus furiosus Csx1 against various nucleic acid substrates. We show that Csx1 is a metal-independent, endoribonuclease that acts selectively on single-stranded RNA and cleaves specifically after adenosines. The RNA cleavage activity of Csx1 is dependent upon a conserved HEPN motif located within the C-terminal domain of the protein. This motif is also key for activity in other known ribonucleases. Collectively, the findings indicate that invader silencing by Type III-B CRISPR-Cas systems relies both on RNA and DNA nuclease activities from the Cmr effector complex as well as on the affiliated, trans-acting Csx1 endoribonuclease.

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RNase T2 Family: Enzymatic Properties, Functional Diversity, and Evolution of Ancient Ribonucleases

Cited by 48 publications

References 146 publications

Differential proteomic analysis of the secretome of Irpex lacteus and other white-rot fungi during wheat straw pretreatment

Differential proteomic analysis of the secretome of Irpex lacteus and other white-rot fungi during wheat straw pretreatment

Evidence for autophagy-dependent pathways of rRNA turnover inArabidopsis

The CRISPR-associated Csx1 protein of Pyrococcus furiosus is an adenosine-specific endoribonuclease

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