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981.
Pan Liu Wen‐Feng Nie Xiansong Xiong Yuhua Wang Yuwei Jiang Pei Huang Xueqiang Lin Guochen Qin Huan Huang Qingfeng Niu Jiamu Du Zhaobo Lang Rosa Lozano‐Duran Jian‐Kang Zhu 《植物学报(英文版)》2021,63(4):772-786
Active DNA demethylation is critical for altering DNA methylation patterns and regulating gene expression. The 5‐methylcytosine DNA glycosylase/lyase ROS1 initiates a base‐excision repair pathway for active DNA demethylation and is required for the prevention of DNA hypermethylation at 1 000s of genomic regions in Arabidopsis. How ROS1 is regulated and targeted to specific genomic regions is not well understood. Here, we report the discovery of an Arabidopsis protein complex that contains ROS1, regulates ROS1 gene expression, and likely targets the ROS1 protein to specific genomic regions. ROS1 physically interacts with a WD40 domain protein (RWD40), which in turn interacts with a methyl‐DNA binding protein (RMB1) as well as with a zinc finger and homeobox domain protein (RHD1). RMB1 binds to DNA that is methylated in any sequence context, and this binding is necessary for its function in vivo. Loss‐of‐function mutations in RWD40, RMB1, or RHD1 cause DNA hypermethylation at several tested genomic regions independently of the known ROS1 regulator IDM1. Because the hypermethylated genomic regions include the DNA methylation monitoring sequence in the ROS1 promoter, plants mutated in RWD40, RMB1, or RHD1 show increased ROS1 expression. Importantly, ROS1 binding to the ROS1 promoter requires RWD40, RMB1, and RHD1, suggesting that this complex dictates ROS1 targeting to this locus. Our results demonstrate that ROS1 forms a protein complex with RWD40, RMB1, and RHD1, and that this novel complex regulates active DNA demethylation at several endogenous loci in Arabidopsis. 相似文献
982.
Pemán J Cantón E Miñana JJ Florez JA Echeverria J Ortega DN Alarcón JM Fontanals D Sard BG Moreno BB Torroba L Ayats J Pérez MÁ Fernández MA Reus FS Natal IF García GR Ezpeleta G Martín-Mazuelos E Iglesias I Rezusta A de Ocariz IR Nieto AG;el Grupo de Estudio FUNGEMYCA 《Revista iberoamericana de micología》2011,28(2):91-99
983.
Celedón G González G Lissi E Cerda T Bascuñant D Lepeley M Pazos F Lanio ME Alvarez C 《Free radical research》2011,45(4):400-408
Stichodactyla heliantus II (St II) is a haemolytic toxin whose activity depends of the characteristics of red blood cells (RBC). Among the factors that may tune the response of the RBC to the toxin activity stand the oxidative status of the cell. This study investigates how pre-oxidation of RBC modifies St II activity employing two oxidants, peroxynitrite and hypochlorous acid. Results show that peroxynitrite-treated RBC are more resistant to St II activity. On the other hand, hypochlorous acid-treated RBC become more susceptible to St II. This contrasting behaviour of both oxidants is related to the modifications elicited in RBC by both oxidant agents. Peroxynitrite does not modify RBC osmotic fragility but reduces anion transport through band 3 protein. This effect, together with an increase in K+ efflux, can explain the increased resistance to the toxin activity. On the other hand, results obtained with hypochlorous acid can be explained in terms of a disruption of the membrane organization without the compensating effect of a reduction in band 3-mediated anion transport. The present results, obtained employing the effect of a model haemolytic toxin on RBC, emphasize the specificity of the RBC response to different endogenous oxidative agents. 相似文献
984.
985.
Gloria Burow John J. Burke Zhanguo Xin Cleve D. Franks 《Molecular breeding : new strategies in plant improvement》2011,28(3):391-402
Soil temperatures at 15°C or below limit germination and seedling establishment for warm season cereal crops such as sorghum
(Sorghum bicolor (L.) Moench) during early-season planting. To better understand the genetics of early-season cold tolerance in sorghum, mapping
of quantitative trait loci (QTL) associated with germination, emergence and vigor using a recombinant inbred mapping population
was carried out. A mapping population consisting of 171 F7–F8 recombinant inbred lines (RILs) derived from the cross between RTx430 (cold-sensitive) and PI610727 (cold-tolerant) was developed
and a genetic map was constructed using 141 microsatellites or simple sequence repeat (SSR) markers. The RILs were evaluated
for cold and optimal temperature germinability in the laboratory, field emergence, and seedling vigor in two locations during
early-season planting. Two or more QTL were detected for all traits, except for seedling vigor, with only one QTL was detected
in the population. A QTL for cold germinability (Germ 12-2.1) showed the highest LOD value and was also associated with optimal germinability. One of the QTL for field emergence, Fearlygerm-9.3, a contribution from PI610727, was found significant in both locations used for the study. This study showed alignment of
QTL in SBi1 (Fearlygerm-1.2 and FGerm30-1.2) with previously reported QTL associated with late field emergence identified from a different mapping population. This indicates
that PI617027 shares some common loci with other known early-season cold-tolerant sorghum germplasm but also harbors novel
QTL that could be useful in introgression of enhanced laboratory germination and early-season field emergence. 相似文献
986.
Background
The oxygen transfer rate (OTR) and dissolved oxygen tension (DOT) play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax) in cultures where the dissolved oxygen tension (DOT) was kept constant. 相似文献987.
988.
Côté HC Gerschenson M Walker UA Miro O Garrabou G Hammond E Villarroya J Giralt M Villarroya F Cinque P Garcia-Arumi E Andreu AL Pinti M Cossarizza A 《Mitochondrion》2011,11(3):520-527
Mitochondrial DNA quantification by qPCR is used in the context of many diseases and toxicity studies but comparison of results between laboratories is challenging. Through two multigroup distributions of DNA samples from human cell lines, the MITONAUTS group anonymously compared mtDNA/nDNA quantification across nine laboratories involved in HIV research worldwide. Eight of the nine sites showed significant correlation between them (mean raw data R(2)=0.664; log(10)-transformed data R(2)=0.844). Although mtDNA/nDNA values were well correlated between sites, the inter-site variability on the absolute measurements remained high with a mean (range) coefficient of variation of 71 (37-212) %. Some variability appeared cell line-specific, probably due to chromosomal alterations or pseudogenes affecting the quantification of certain genes, while within cell line variability was likely due to differences in calibration of the standard curves. The use of two mtDNA and two single copy nDNA genes with highly specific primers to quantify each genome would help address copy number variants. Our results indicate that sample shipment must be done frozen and that absolute mtDNA/nDNA ratio values cannot readily be compared between laboratories, especially if assessing cultured cell mtDNA content. However, within laboratory and relative mtDNA/nDNA comparisons between laboratories should be reliable. 相似文献
989.
Telomerase serves to maintain telomeric repeat sequences at the ends of chromosomes. However, telomerase can also add telomeric repeat sequences at DNA double-strand breaks (DSBs), a process called chromosome healing. Here, we employed a method of inducing DSBs near telomeres to query the role of two proteins, PIF1 and NBS1, in chromosome healing in mammalian cells. PIF1 was investigated because the PIF1 homolog in Saccharomyces cerevisiae inhibits chromosome healing, as shown by a 1000-fold increase in chromosome in PIF1-deficient cells. NBS1 was investigated because the functional homolog of NBS1 in S. cerevisiae, Xrs2, is part of the Mre11/Rad50/Xrs2 complex that is required for chromosome healing due to its role in the processing of DSBs and recruitment of telomerase. We found that disruption of mPif1 had no detectable effect on the frequency of chromosome healing at DSBs near telomeres in murine embryonic stem cells. Moreover, the Nbs1(ΔB) hypomorph, which is defective in the processing of DSBs, also had no detectable effect on the frequency of chromosome healing, DNA degradation, or gross chromosome rearrangements (GCRs) that result from telomeric DSBs. Although we cannot rule out small changes in chromosome healing using this system, it is clear from our results that knockout of PIF1 or the Nbs1(ΔB) hypomorph does not result in large differences in chromosome healing in murine cells. These results represent the first genetic assessment of the role of these proteins in chromosome healing in mammals, and suggest that murine cells have evolved mechanisms to ensure the functional redundancy of Pif1 or Nbs1 in the regulation of chromosome healing. 相似文献