RNA m^(5)C甲基化修饰在肿瘤中的研究进展

5-甲基胞嘧啶(5-methylcytosine,m^(5)C)是RNA中重要的甲基化修饰之一,也是近年来的研究热点。随着甲基化测序技术的发展,在编码RNA及非编码RNA中均证实存在大量的m5C甲基化修饰。RNA m^(5)C甲基化修饰受m^(5)C甲基转移酶、去甲基化酶及m5C甲基化结合蛋白的调控。m^(5)C甲基化修饰调节RNA的稳定性、转运、翻译和压力应激等,并参与调节肿瘤的发生发展、侵袭转移、肿瘤耐药等进程。本文对RNA m^(5)C甲基化修饰的调控机制、功能以及在肿瘤中的研究进展进行综述,以期为肿瘤诊治研究提供新思路。

Overexpression of a BRASSINAZOLE RESISTANT 1 homolog attenuates drought tolerance by suppressing the expression of PLETHORA-LIKE 1 in Setaria italica

Two potential BRASSINAZOLE RESISTANT 1 (BZR1) homologs were downregulated by brassinosteroids(BRs) in Setaria italica roots.Functional analysis showed that BR regulates the dephosphorylation and nuclear localization of Si BZR1 and that Si BZR1 binds conserved BZR1-recognizing cis elements.In comparison with the wild type,Si BZR1-overexpressing S.italica seedlings were more sensitive to BR-inhibited primary root growth and drought stress,indicating that Si BZR1 is a positive regulator of BR signaling and a negative regulator of drought tolerance in S.italica.PLETHORA-LIKE 1 (Si PLT-L1) was found to be a direct target gene of Si BZR1 in S.italica roots.The expression of Si PLT-L1 was downregulated by Si BZR1.Si PLT-L1-overexpressing S.italica was less sensitive to BR-inhibited root growth and more tolerant to drought stress,possibly owing to the upregulation of drought-inducible Dehydrin-family genes.

Low Resource Chinese Geological Text Named Entity Recognition Based on Prompt Learning

Geological reports are a significant accomplishment for geologists involved in geological investigations and scientific research as they contain rich data and textual information.With the rapid development of science and technology,a large number of textual reports have accumulated in the field of geology.However,many non-hot topics and non-English speaking regions are neglected in mainstream geoscience databases for geological information mining,making it more challenging for some researchers to extract necessary information from these texts.Natural Language Processing(NLP)has obvious advantages in processing large amounts of textual data.The objective of this paper is to identify geological named entities from Chinese geological texts using NLP techniques.We propose the RoBERTa-Prompt-Tuning-NER method,which leverages the concept of Prompt Learning and requires only a small amount of annotated data to train superior models for recognizing geological named entities in low-resource dataset configurations.The RoBERTa layer captures context-based information and longer-distance dependencies through dynamic word vectors.Finally,we conducted experiments on the constructed Geological Named Entity Recognition(GNER)dataset.Our experimental results show that the proposed model achieves the highest F1 score of 80.64%among the four baseline algorithms,demonstrating the reliability and robustness of using the model for Named Entity Recognition of geological texts.

Heat Shock Factor A1s are required for phytochrome-interacting factor 4-mediated thermomorphogenesis in Arabidopsis

Thermomorphogenesis and the heat shock(HS)response are distinct thermal responses in plants that are regulated by PHYTOCHROME-INTERACTING FACTOR 4(PIF4)and HEAT SHOCK FACTOR A1s(HSFA1s),respectively.Little is known about whether these responses are interconnected and whether they are activated by similar mechanisms.An analysis of transcriptome dynamics in response to warm temperature(28℃)treatment revealed that 30 min of exposure activated the expression of a subset of HSFA1 target genes in Arabidopsis thaliana.Meanwhile,a loss-of-function HSFA1 quadruple mutant(hsfa1-cq)was insensitive to warm temperature-induced hypocotyl growth.In hsfa1-cq plants grown at 28℃,the protein and transcript levels of PIF4 were greatly reduced,and the circadian rhythm of many thermomorphogenesis-related genes(including PIF4)was disturbed.Additionally,the nuclear localization of HSFA1s and the binding of HSFA1d to the PIF4 promoter increased following warm temperature exposure,whereas PIF4 overexpression in hsfa1-cq partially rescued the altered warm temperature-induced hypocotyl growth of the mutant.Taken together,these results suggest that HSFA1s are required for PIF4 accumulation at a warm temperature,and they establish a central role for HSFA1s in regulating both thermomorphogenesis and HS responses in Arabidopsis.

Boosting wheat functional genomics via an indexed EMS mutant library of KN9204

A better understanding of wheat functional genomics can improve targeted breeding for better agronomic traits and environmental adaptation.However,the lack of gene-indexed mutants and the low transformation efficiency of wheat limit in-depth gene functional studies and genetic manipulation for breeding.In this study,we created a library for KN9204,a popular wheat variety in northern China,with a reference genome,transcriptome,and epigenome of different tissues,using ethyl methyl sulfonate(EMS)mutagenesis.This library contains a vast developmental diversity of critical tissues and transition stages.Exome capture sequencing of 2090 mutant lines using KN9204 genome-designed probes revealed that 98.79%of coding genes had mutations,and each line had an average of 1383 EMS-type SNPs.We identified new allelic variations for crucial agronomic trait-related genes such as Rht-D1,Q,TaTB1,and WFZP.We tested 100 lines with severemutations in 80 NAC transcription factors(TFs)under drought and salinity stress and identified 13 lines with altered sensitivity.Further analysis of three lines using transcriptome and chromatin accessibility data revealed hundreds of direct NAC targets with altered transcription patterns under salt or drought stress,including SNAC1,DREB2B,CML16,and ZFP182,factors known to respond to abiotic stress.Thus,we have generated and indexed a KN9204 EMS mutant library that can facilitate functional genomics research and offer resources for genetic manipulation of wheat.

Molecular mechanisms governing plant responses to high temperatures

The increased prevalence of high temperatures （HTs） around the world is a major global concern, as they dramatically affect agronomic productivity. Upon HT exposure, plants sense the temperature change and initiate cellular and metabolic responses that enable them to adapt to their new environmental conditions.Decoding the mechanisms by which plants cope with HT will facilitate the development of molecular markers to enable the production of plants with improved thermotolerance. In recent decades, genetic, physiological, molecular, and biochemical studies have revealed a number of vital cellular components and processes involved in thermoresponsive growth and the acquisition of thermo- tolerance in plants. This review summarizes the major mechanisms involved in plant HT responses, with a special focus on recent discoveries related to plant thermosensing, heat stress signaling, and HT-regulated gene expression networks that promote plant adaptation to elevated environmental temperatures.

BZR1 Family Transcription Factors Function Redundantly and Indispensably in BR Signaling but Exhibit BRI1-Independent Function in Regulating Anther Development in Arabidopsis

BRASSINAZOLE-RESISTANT 1 family proteins(BZRs)are central transcription factors that govern brassinosteroid(BR)-regulated gene expression and plant growth.However,it is unclear whether there exists a BZR-independent pathway that mediates BR signaling.In this study,we found that disruption of all BZRs in Arabidopsis generated a hextuple mutant(bzr-h)displaying vegetative growth phenotypes that were almost identical to those of the null mutant of three BR receptors,bri1brl1brl3(bri-t).By RNA sequencing,we found that global gene expression in bzr-h was unaffected by 2 h of BR treatment.The anthers of bzr-h plants were loculeless,but a similar phenotype was not observed in bri-t,suggesting that BZRs have a BR signaling-independent regulatory role in anther development.By real-time PCR and in situ hybridization,we found that the expression of SPOROCYTELESS(SPL),which encodes a transcription factor essential for anther locule development,was barely detectable in bzr-h,suggesting that BZRs regulate locule development by affecting SPL expression.Our findings reveal that BZRs are indispensable transcription factors required for both BR signaling and anther locule development,providing new insight into the molecular mechanisms underlying the microsporogenesis in Arabidopsis.

The Brassinosteroid-Activated BRI1 Receptor Kinase Is Switched off by Dephosphorylation Mediated by Cytoplasm-Localized PP2A B＇ Subunits

Brassinosteroid （BR） binding activates the receptor kinase BRI1 by inducing heterodimerization with its co- receptor kinase BAK1; however, the mechanisms that reversibly inactivate BRI1 remain unclear. Here we show that cytoplasm-localized protein phosphatase 2A （PP2A） B＇ regulatory subunits interact with BRI1 to mediate its dephosphorylation and inactivation. Loss-of-function and overexpression experiments showed that a group of PP2A B＇ regulatory subunits, represented by B＇η, negatively regulate BR signaling by decreasing BRI1 phosphorylation. BR increases the expression levels of these B＇ subunits, and B/TI interacts preferentially with phosphorylated BRI1, suggesting that the dynamics of BR signaling are modu- lated by the PP2A-mediated feedback inactivation of BRI1. Compared with PP2A B＇α and B＇β, which promote BR responses by dephosphorylating the downstream transcription factor BZR1, the BRI1- inactivating B＇ subunits showed similar binding to BRI1 and BZR1 but distinct subcellular localization. Alteration of the nuclear/cytoplasmic localization of the B＇ subunits revealed that cytoplasmic PP2A de- phosphorylates BRI1 and inhibits the BR response, whereas nuclear PP2A dephosphorylates BZR1 and ac- tivates the BR response. Our findings not only identify the PP2A regulatory B subunits that mediate the binding and dephosphorylation of BRI1, but also demonstrate that the subcellular localization of PP2A specifies its substrate selection and distinct effects on BR signaling.

Brassinosteroids regulate outer ovule integument growth in part via the control of INNER NO OUTER by BRASSINOZOLE‐RESISTANT family transcription factors

Brassinosteroids(BRs)play important roles in regulating plant reproductive processes.BR signaling or BR biosynthesis null mutants do not produce seeds under natural conditions,but the molecular mechanism underlying this infertility is poorly understood.In this study,we report that outer integument growth and embryo sac development were impaired in the ovules of the Arabidopsis thaliana BR receptor null mutant bri1-116.Gene expression and RNA-seq analyses showed that the expression of INNER NO OUTER(INO),an essential regulator of outer integument growth,was significantly reduced in the bri1-116 mutant.Increased INO expression due to overexpression or increased transcriptional activity of BRASSINAZOLE-RESISTANT 1(BZR1)in the mutant alleviated the outer integument growth defect in bri1-116 ovules,suggesting that BRs regulate outer integument growth partially via BZR1-mediated transcriptional regulation of INO.Meanwhile,INO expression in bzr-h,a null mutant for all BZR1 family genes,was barely detectable;and the outer integument of bzr-h ovules had much more severe growth defects than those of the bri1-116 mutant.Together,our findings establish a new role for BRs in regulating ovule development and suggest that BZR1 family transcription factors might regulate outer integument growth through both BRI1-dependent and BRI1-independent pathways.