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81.
Gerald
Ryan
R Aquino Nicolai Krogh Philipp Hackert Roman Martin Jimena
Davila Gallesio Robert W van
Nues Claudia Schneider Nicholas
J Watkins Henrik Nielsen Katherine E Bohnsack Markus
T Bohnsack 《Nucleic acids research》2021,49(7):4066
RNA helicases play important roles in diverse aspects of RNA metabolism through their functions in remodelling ribonucleoprotein complexes (RNPs), such as pre-ribosomes. Here, we show that the DEAD box helicase Dbp3 is required for efficient processing of the U18 and U24 intron-encoded snoRNAs and 2′-O-methylation of various sites within the 25S ribosomal RNA (rRNA) sequence. Furthermore, numerous box C/D snoRNPs accumulate on pre-ribosomes in the absence of Dbp3. Many snoRNAs guiding Dbp3-dependent rRNA modifications have overlapping pre-rRNA basepairing sites and therefore form mutually exclusive interactions with pre-ribosomes. Analysis of the distribution of these snoRNAs between pre-ribosome-associated and ‘free’ pools demonstrated that many are almost exclusively associated with pre-ribosomal complexes. Our data suggest that retention of such snoRNPs on pre-ribosomes when Dbp3 is lacking may impede rRNA 2′-O-methylation by reducing the recycling efficiency of snoRNPs and by inhibiting snoRNP access to proximal target sites. The observation of substoichiometric rRNA modification at adjacent sites suggests that the snoRNPs guiding such modifications likely interact stochastically rather than hierarchically with their pre-rRNA target sites. Together, our data provide new insights into the dynamics of snoRNPs on pre-ribosomal complexes and the remodelling events occurring during the early stages of ribosome assembly. 相似文献
82.
83.
Abstract The biogenesis of most eukaryotic kinds of RNA requires nuclear export, which is mediated by a variety of specific nuclear transport receptors. The nuclear export receptors Exportin-t (Exp-t) and Exportin 5 (Exp5), and their homologues, are involved in the export of transfer RNA to the cytoplasm. Exp5 is further involved in additional nucleocytoplasmic transport pathways, which include nuclear export of microRNA precursors (pre-miRNAs) and pre-60S ribosomal subunits. Inactivation of Exp5 results in nuclear accumulation of pre-miRNAs and perturbation of gene expression, and its mutation was recently found in malignant diseases. Here, we compare the cellular function of Exp5 and Exp-t with focus on Exp5 substrates and its role in diseases. 相似文献
84.
Kostyantyn V. Dmytruk Justyna Ruchala Daria V. Fedorovych Roman D. Ostapiv Andriy A. Sibirny 《Biotechnology journal》2020,15(7)
Riboflavin (vitamin B2) is an indispensable nutrient for humans and animals, since it is the precursor of the essential coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), involved in variety of metabolic reactions. Riboflavin is produced on commercial scale and is used for feed and food fortification purposes, and in medicine. Until recently, the mutant strains of the flavinogenic yeast Candida famata were used in industry for riboflavin production. Guanosine triphosphate is the immediate precursor of riboflavin synthesis. Therefore, the activation of metabolic flux toward purine nucleotide biosynthesis is a promising approach to improve riboflavin production. The phosphoribosyl pyrophosphate synthetase and phosphoribosyl pyrophosphate amidotransferase are the rate limiting enzymes in purine biosynthesis. Corresponding genes PRS3 and ADE4 from yeast Debaryomyces hansenii are modified to avoid feedback inhibition and cooverexpressed on the background of a previously constructed riboflavin overproducing strain of C. famata. Constructed strain accumulates twofold more riboflavin when compared to the parental strain. 相似文献
85.
Xu X Martin B Comstock JP Vision TJ Tauer CG Zhao B Pausch RC Knapp S 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,117(2):221-233
Carbon isotope composition (delta(13)C) and leaf water-use efficiency vary in concert in C3 plants, making delta(13)C useful as a proxy for plant water-use efficiency. A QTL for delta(13)C was detected in the Solanum pennellii chromosome fragment of IL5-4, an introgression line with S. lycopersicum cv. M82 background. M82 and IL 5-4 were crossed, and RFLP markers in the target region converted to PCR-based markers. Forty-one recombinants with an introgression fragment ranging in length from 1.1 to 11.4 cM were identified by marker assisted selection (MAS) among approximately 2000 F2 plants. A total of 29 markers were mapped within the introgression fragment unique to IL5-4. These markers divided the about 9 cM target region into nine intervals. A dominant QTL for delta(13)C, designated QWUE5.1 that explained 25.6% of the total phenotypic variance was mapped to an interval about 2.2 cM long. Twenty-one plants with a S. pennellii chromosome fragment shortened to a length of 2.0-9.1 cM by a second recombination event were generated by MAS of 1,125 F4 plants. Two near isogenic lines with high delta(13)C (small negative value) and carrying QWUE5.1 on the shortest introgression fragments (about 7.0 cM) were identified. The markers and genetic stocks developed are valuable for cloning the gene underlying QWUE5.1, MAS of QWUE5.1, and fine-mapping genes/QTL located in this region. 相似文献
86.
Jesús Rodríguez-Calcerrada Jose Alberto Pardos Luis Gil Peter B. Reich Ismael Aranda 《Plant Ecology》2008,195(2):273-285
In order to understand better the ecology of the temperate species Quercus petraea and the sub-Mediterranean species Quercus pyrenaica, two deciduous oaks, seedlings were raised in two contrasting light environments (SH, 5.3% full sunlight vs. HL, 70% full
sunlight) for 2 years, and a subset of the SH seedlings were transferred to HL (SH–HL) in the summer of the second year. We
predicted that Q. pyrenaica would behave more as a stress-tolerant species, with lower specific leaf area (SLA), allocation to leaf mass, and growth
rate and less responsiveness to light in these metrics, than Q. petraea, presumed to be more competitive when resources, especially light and water, are abundant. Seedlings of Q. petraea had larger leaves with higher SLA, and exhibited a greater relative growth rate (RGR) in both SH and HL. They also displayed
a higher proportion of biomass in stems (SMF), and a lower root to shoot ratio (R/S) in HL than those of Q. pyrenaica, which sprouted profusely, and had higher rates of photosynthesis (An) and stomatal conductance (gwv), but lower whole-plant net assimilation rate (NAR). On exposure to a sudden increase in light, SH–HL seedlings of both species
showed a short period of photoinhibition, but fully acclimated photosynthetic features within 46 days after transference;
height, main stem diameter, RGR and NAR all increased at the end of the experiment compared to SH seedlings, with these increases
more pronounced in Q. petraea. Observed differences in traits and responses to light confirmed a contrasting ecology at the seedling stage in Q. petraea and Q. pyrenaica in consonance with differences in their overall distribution. We discuss how the characteristics of Q. petraea may limit the availability of suitable regeneration niches to microsites of high-resource availability in marginal populations
of Mediterranean climate, with potential negative consequences for its recruitment under predicted climatic changes. 相似文献
87.
88.
Plasmid DNA for biopharmaceutical applications is mainly produced in E. coli cells. The first and most crucial step for recovering the plasmid is the cell lysis. Governed by the physico-chemical properties of the polynucleotide, alkaline lysis has been the lysis-method of choice. This chemical disintegration technique was initially developed for the lab scale and non-pharmaceutical applications. A continuous, fully automated and closed system combining alkaline lysis, neutralization and clarification in one gentle and generic operation was developed. This system consists of a three units. One unit controls mixing and contact time during the alkaline treatment, another one controls the neutralization and the concurrent formation of flocs and a third one the separation of flocs and pDNA containing lysate. Based on optimization experiments the selected process parameters resulted in yields up to 100% and homogeneities comparable to that obtained by gentle manual lysis. The process does not need enzymes and it is scalable and routinely used for cGMP-production of pharmaceutical grade plasmid DNA from 200 L fermentations. 相似文献
89.
90.
Campan M Moffitt M Houshdaran S Shen H Widschwendter M Daxenbichler G Long T Marth C Laird-Offringa IA Press MF Dubeau L Siegmund KD Wu AH Groshen S Chandavarkar U Roman LD Berchuck A Pearce CL Laird PW 《PloS one》2011,6(12):e28141