Roles of NAC transcription factors in cotton

Climate deterioration,water shortages,and abiotic stress are the main threats worldwide that seriously affect cotton growth,yield,and fiber quality.Therefore,research on improving cotton yield and tolerance to biotic and abiotic stresses is of great importance.The NAC proteins are crucial and plant-specific transcription factors(TFs)that are involved in cotton growth,development,and stress responses.The comprehensive utilization of cotton NAC TFs in the improvement of cotton varieties through novel biotechnological methods is feasible.Based on cotton genomic data,genome-wide identification and analyses have revealed potential functions of cotton NAC genes.Here,we comprehensively summarize the recent progress in understanding cotton NAC TFs roles in regulating responses to drought,salt,and Verticillium wilt-related stresses,as well as leaf senescence and the development of fibers,xylem,and glands.The detailed regulatory network of NAC proteins in cotton is also elucidated.Cotton NAC TFs directly bind to the promoters of genes associated with ABA biosynthesis and secondary cell-wall formation,participate in several biological processes by interacting with related proteins,and regulate the expression of downstream genes.Studies have shown that the overexpression of NAC TF genes in cotton and other model plants improve their drought or salt tolerance.This review elucidates the latest findings on the functions and regulation of cotton NAC proteins,broadens our understanding of cotton NAC TFs,and lays a fundamental foundation for further molecular breeding research in cotton.

High-throughput screening system of citrus bacterial cankerassociated transcription factors and its application to the regulation of citrus canker resistance

One of the main diseases that adversely impacts the global citrus industry is citrus bacterial canker(CBC),caused by the bacteria Xanthomonas citri subsp.citri(Xcc).Response to CBC is a complex process,with both proteinDNA as well as protein–protein interactions for the regulatory network.To detect such interactions in CBC resistant regulation,a citrus high-throughput screening system with 203 CBC-inducible transcription factors(TFs),were developed.Screening the upstream regulators of target by yeast-one hybrid(Y1H)methods was also performed.A regulatory module of CBC resistance was identified based on this system.One TF(CsDOF5.8)was explored due to its interactions with the 1-kb promoter fragment of CsPrx25,a resistant gene of CBC involved in reactive oxygen species(ROS)homeostasis regulation.Electrophoretic mobility shift assay(EMSA),dual-LUC assays,as well as transient overexpression of CsDOF5.8,further validated the interactions and transcriptional regulation.The CsDOF5.8–CsPrx25 promoter interaction revealed a complex pathway that governs the regulation of CBC resistance via H2O2homeostasis.The high-throughput Y1H/Y2H screening system could be an efficient tool for studying regulatory pathways or network of CBC resistance regulation.In addition,it could highlight the potential of these candidate genes as targets for efforts to breed CBC-resistant citrus varieties.

Transcription factor OsSPL10 interacts with OsJAmyb to regulate blast resistance in rice

Transcription factors(TFs)play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens.OsSPL10(SQUAMOSA promoter binding protein-like10)is an important TF regulating trichome development and salt tolerance in rice.Here we report that knockout of OsSPL10 reduces whereas its overexpression enhances rice resistance to blast disease.OsSPL10 positively regulates chitin-induced immune responses including reactive oxygen species(ROS)burst and callose deposition.We show that OsSPL10 physically associates with OsJAmyb,an important TF involved in jasmonic acid(JA)signaling,and positively regulates its protein stability.We then prove that OsJAmyb positively regulates resistance to blast.Our results reveal a molecular module consisting of OsSPL10 and OsJAmyb that positively regulates blast resistance.

Wild soybean(Glycine soja)transcription factor GsWRKY40 plays positive roles in plant salt tolerance

Wild soybean(Glycine soja),a relative of cultivated soybean,shows high adaptability to adverse environmental conditions.We identified and characterized a wild soybean transcription factor gene,GsWRKY40,that promotes plant salt stress.GsWRKY40 was highly expressed in wild soybean roots and was up-regulated by salt treatment.GsWRKY40 was localized in nucleus and demonstrated DNA-binding activities but without transcriptional activation.Mutation and overexpression of GsWRKY40 altered salt tolerance of Arabidopsis plants.To understand the molecular mechanism of GsWRKY40 in regulating plant salt resistance,we screened a cDNA library and identified a GsWRKY40 interacting protein GsbHLH92 by using yeast two-hybrid approach.The physical interaction of GsWRKY40 and GsbHLH92 was confirmed by co-immunoprecipitation(co-IP),GST pull-down,and bimolecular fluorescence complementation(BiFC)techniques.Intriguingly,co-overexpression of GsWRKY40 and GsbHLH92 resulted in higher salt tolerance and lower ROS levels than overexpression of GsWRKY40 or GsbHLH92 in composite soybean plants,suggesting that GsWRKY40 and GsbHLH92 may synergistically regulate plant salt resistance through inhibiting ROS production.qRT-PCR data indicated that the expression level of GmSPOD1 gene encoding peroxidase was cooperatively regulated by GsWRKY40 and GsbHLH92,which was confirmed by using a dual luciferase report system and yeast one-hybrid experiment.Our study reveals a pathway that GsWRKY40 and GsbHLH92 collaboratively up-regulate plant salt resistance through impeding GmSPOD1 expression and reducing ROS levels,providing a novel perspective on the regulatory mechanisms underlying plant tolerance to abiotic stresses.

The BEL1-like transcription factor GhBLH5-A05 participates in cotton response to drought stress

Drought stress impairs crop growth and development.BEL1-like family transcription factors may be involved in plant response to drought stress,but little is known of the molecular mechanism by which these proteins regulate plant response and defense to drought stress.Here we show that the BEL1-like transcription factor GhBLH5-A05 functions in cotton(Gossypium hirsutum)response and defense to drought stress.Expression of GhBLH5-A05 in cotton was induced by drought stress.Overexpression of GhBLH5-A05 in both Arabidopsis and cotton increased drought tolerance,whereas silencing GhBLH5-A05 in cotton resulted in elevated sensitivity to drought stress.GhBLH5-A05 binds to cis elements in the promoters of GhRD20-A09 and GhDREB2C-D05 to activate the expression of these genes.GhBLH5-A05 interacted with the KNOX transcription factor GhKNAT6-A03.Co-expression of GhBLH5-A05 and GhKNAT6-A03 increased the transcription of GhRD20-A09 and GhDREB2C-D05.We conclude that GhBLH5-A05 acts as a regulatory factor with GhKNAT6-A03 functioning in cotton response to drought stress by activating the expression of the drought-responsive genes GhRD20-A09 and GhDREB2C-D05.

Sugarcane transcription factor ScWRKY4 negatively regulates resistance to pathogen infection through the JA signaling pathway

WRKY transcription factors,transcriptional regulators unique to plants,play an important role in defense response to pathogen infection.However,the resistance mechanisms of WRKY genes in sugarcane remain unclear.In the present study,gene ontology(GO)enrichment analysis revealed that WRKY gene family in sugarcane was extensively involved in the response to biotic stress and in defense response.We identified gene ScWRKY4,a classⅡc member of the WRKY gene family,in sugarcane cultivar ROC22.This gene was induced by salicylic acid(SA)and methyl jasmonate(MeJA)stress.Interestingly,expression of ScWRKY4 was down-regulated in smut-resistant sugarcane cultivars but up-regulated in smutsusceptible sugarcane cultivars infected with Sporisorium scitamineum.Moreover,stable overexpression of the ScWRKY4 gene in Nicotiana benthamiana enhanced susceptibility to Fusarium solani var.coeruleum and caused down-regulated expression of immune marker-related genes.Transcriptome analysis indicated suppressed expression of most JAZ genes in the signal transduction pathway.ScWRKY4 interacted with ScJAZ13 to repress its expression.We thus hypothesized that the ScWRKY4 gene was involved in the regulatory network of plant disease resistance,most likely through the JA signaling pathway.The present study depicting the molecular involvement of ScWRKY4 in sugarcane disease resistance lays a foundation for future investigation.

Gene expression,transcription factor binding and histone modification predict leaf adaxial-abaxial polarity related genes

Leaf adaxial-abaxial(ad-abaxial)polarity is crucial for leaf morphology and function,but the genetic machinery governing this process remains unclear.To uncover critical genes involved in leaf ad-abaxial patterning,we applied a combination of in silico prediction using machine learning(ML)and experimental analysis.A Random Forest model was trained using genes known to influence ad-abaxial polarity as ground truth.Gene expression data from various tissues and conditions as well as promoter regulation data derived from transcription factor chromatin immunoprecipitation sequencing(ChIP-seq)was used as input,enabling the prediction of novel ad-abaxial polarity-related genes and additional transcription factors.Parallel to this,available and newly-obtained transcriptome data enabled us to identify genes differentially expressed across leaf ad-abaxial sides.Based on these analyses,we obtained a set of 111 novel genes which are involved in leaf ad-abaxial specialization.To explore implications for vegetable crop breeding,we examined the conservation of expression patterns between Arabidopsis and Brassica rapa using single-cell transcriptomics.The results demonstrated the utility of our computational approach for predicting candidate genes in crop species.Our findings expand the understanding of the genetic networks governing leaf ad-abaxial differentiation in agriculturally important vegetables,enhancing comprehension of natural variation impacting leaf morphology and development,with demonstrable breeding applications.

Cu Stress-Induced Transcriptome Alterations in Sorghum and Expression Analysis of the Transcription Factor-Encoding Gene SbWRKY24

Sorghum is not only an important bio-energy crop but also a vital raw material for brewing.Exogenous copper affects the growth and metabolism of crops in specific ways.This study identified 8475 differentially expressed genes(DEGs)by high-throughput transcriptome sequencing in the sorghum cultivar‘Jinnuoliang 2’after 24 h of treatment with 10 mM CuSO4.Using GO analysis,476 genes were functionally annotated,which were mainly related to catabolism and biosynthetic processes.Additionally,90 pathways were annotated by employing the KEGG analysis.Among them,glutathione metabolism and peroxisome were induced,while photosynthesis,photosynthesis-antenna protein,and carbon sequestration of photosynthetic organisms were inhibited.Of the DEGs,399 were identified to encode transcription factors belonging to 49 families.This study also identified a WRKY transcription factor-encoding gene SbWRKY24 from the transcriptome data.For studying its function,the relative expression levels of SbWRKY24 in roots and leaves post-treatment with different growth hormones and exposure to a variety of abiotic stresses were detected by RT-qPCR.SbWRKY24 showed treatment-and tis-sue-specific expression patterns,indicating its unique role in stress tolerance.This study lays a theoretical basis for the functional exploration of SbWRKY24,elucidating the mechanism of copper resistance,and elaborating on the stress responses in sorghum.It also guides the exploration of the molecular mechanism of copper ions inducing intracellular signal transduction pathways.

Prognostic significance of oligodendrocyte transcription factor 2 expression in glioma patients:A systematic review and metaanalys

BACKGROUND Gliomas are the most common primary central nervous system neoplasm.Despite recent advances in the diagnosis and treatment of gliomas,patient prognosis remains dismal.Therefore,it is imperative to identify novel diagnostic biomarkers and therapeutic targets of glioma to effectively improve treatment outcomes.AIM To investigate the association between oligodendrocyte transcription factor 2(Olig2)expression and the outcomes of glioma patients.METHODS The PubMed,Embase,Cochrane Library,and China National Knowledge Infrastructure databases were searched for studies(published up to October 2023)that investigated the relationship between Olig2 expression and prognosis of glioma patients.The quality of the studies was assessed using the Newcastle Ottawa Scale.Data analyses were performed using Stata Version 12.0 software.RESULTS A total of 1205 glioma patients from six studies were included in the metaanalysis.High Olig2 expression was associated with better outcomes in glioma patients[hazard ratio(HR):0.81;95%(confidence interval)CI:0.51-1.27;P=0.000].Furthermore,the results of subgroup meta-analysis showed that high expression of Olig2 was associated with poor overall survival in European patients(HR:1.34;95%CI:0.79-2.27)and better prognosis in Asian patients(HR:0.43;95%CI:0.22-0.84).The sensitivity analysis showed that no single study had a significant effect on pooled HR,and there was also no indication of publication bias according to the Egger’s and Begger’s P value test or funnel plot test.CONCLUSION High Olig2 expression may have a positive impact on the prognosis of glioma patients,and should be investigated further as a prognostic biomarker and therapeutic target for glioma.

Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy

Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecular underpinnings of their development.This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches,focusing on the activation of transcription factor EB.Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies,such as exercise,calorie restriction,rapamycin,and metformin,in patients and animal models of these common retinal diseases.The review critically assesses the role of transcription factor EB in retinal biology during aging,its neuroprotective effects,and its therapeutic potential for retinal disorders.The impact of transcription factor EB on retinal aging is cell-specific,influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways.In vascular endothelial cells,transcription factor EB controls important processes,including endothelial cell proliferation,endothelial tube formation,and nitric oxide levels,thereby influencing the inner blood-retinal barrier,angiogenesis,and retinal microvasculature.Additionally,transcription factor EB affects vascular smooth muscle cells,inhibiting vascular calcification and atherogenesis.In retinal pigment epithelial cells,transcription factor EB modulates functions such as autophagy,lysosomal dynamics,and clearance of the aging pigment lipofuscin,thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization.These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis,neuronal synapse plasticity,energy metabolism,microvasculature,and inflammation,ultimately offering protection against retinal aging and diseases.The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases.Therefore,it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects.

Characteristics and expression of the TCP transcription factors family in Allium senescens reveal its potential roles in drought stress responses

Allium senescens,is an important economic and ecological grassland plant with drought-resistant characteristics.A TCP protein transcription factor is important in the regulation of plant development and adverse responses.However,the mechanism by which TCP transcription functions in drought resistance in Allium senescens is still not clear.Here,we obtained a total of 190,305 transcripts with 115,562 single gene clusters based on RNA-Seq sequencing of Allium senescens under drought stress.The total number of bases was 97,195,096 bp,and the average length was 841.06 bp.Furthermore,we found that there were eight genes of the TCP family that showed an upregulated expression trend under drought stress in Allium senescens.We carried out an investigation to determine the evolution and function of the AsTCP family and how they produce an effect in drought resistance.The 14 AsTCP genes were confirmed and divided into class I and class II containing CIN and CYC/TBI subfamilies,respectively.We also found that the expression of AsTCP17 was remarkably upregulated with drought treatment.Besides,the transformation of AsTCP17 in Arabidopsis revealed that the protective enzymes,namely polyphenol oxidase(POD)and superoxide dismutase(SOD),were increased by 0.4 and 0.8 times,respectively.Chlorophyll content was also increased,while the H2O2 and malondialdehyde(MDA)contents were decreased.Staining assays with 3,3′-diaminobenzidine(DAB)also suggested that the AsTCP17 downregulates reactive oxygen species(ROS)accumulation.In addition,overexpression of the AsTCP17 affected the accumulation of drought-related hormones in plants,and the synthesis of ABA.The expression of AtSVP and AtNCED3,related ABA synthesis pathway genes,indicated that the level of expression of AtSVP and AtNCED3 was obviously enhanced,with the overexpression of line 6 showing a 20.6-fold and 7.0-fold increase,respectively.Taken together,our findings systematically analyze the AsTCPs family at the transcriptome expression level in Allium senescens,and we also demonstrated that AsTCP17 protein,as a positive regulator,was involved in drought resistance of Allium senescens.In addition,our research contributes to the comprehensive understanding of the drought stress defense mechanism in herbaceous plants.

Comparative transcriptome analysis of the climacteric of apple fruit uncovers the involvement of transcription factors affecting ethylene biosynthesis

Apple(Malus domestica)fruit generally undergoes a climacteric.During its ripening process,there is a peak in ethylene release and its firmness simultaneously decreases.Although more in-depth research into the mechanism of climacteric-type fruit ripening is being carried out,some aspects remain unclear.In this study,we compared the transcriptomes of 0-Pre and 15-Post(pre-and post-climacteric fruit),and 15-Post and 15-MCP[fruit treated with 1-MCP(1-methylcyclopropene)].Various transcription factors,such as MADS-box,ERF,NAC,Dof and SHF were identified among the DEGs(differential gene expressions).Furthermore,these transcription factors were selected for further validation analysis by qRT-PCR.Moreover,yeast one hybrid(Y1H),β-glucuronidase(GUS)transactivation assay and dual-luciferase reporter assay showed that MdAGL30,MdAGL104,MdERF008,MdNAC71,MdDof1.2,MdHSFB2a and MdHSFB3 bound to MdACS1 promoter and directly regulated its transcription,thereby regulating ethylene biosynthesis in apple fruit.Our results provide useful information and new insights for research on apple fruit ripening.

Identification of the target genes of AhTWRKY24 and AhTWRKY106 transcription factors reveals their regulatory network in Arachis hypogaea cv.Tifrunner using DAP-seq

WRKY transcription factors(TFs)have been identified as important core regulators in the responses of plants to biotic and abiotic stresses.Cultivated peanut(Arachis hypogaea)is an important oil and protein crop.Previous studies have identified hundreds of WRKY TFs in peanut.However,their functions and regulatory networks remain unclear.Simultaneously,the AdWRKY40 TF is involved in drought tolerance in Arachis duranensis and has an orthologous relationship with the AhTWRKY24 TF,which has a homoeologous relationship with AhTWRKY106 TF in A.hypogaea cv.Tifrunner.To reveal how the homoeologous AhTWRKY24 and AhTWRKY106 TFs regulate the downstream genes,DNA affinity purification sequencing(DAP-seq)was performed to detect the binding sites of TFs at the genome-wide level.A total of 3486 downstream genes were identified that were collectively regulated by the AhTWRKY24 and AhTWRKY106 TFs.The results revealed that W-box elements were the binding sites for regulation of the downstream genes by AhTWRKY24 and AhTWRKY106 TFs.A gene ontology enrichment analysis indicated that these downstream genes were enriched in protein modification and reproduction in the biological process.In addition,RNA-seq data showed that the AhTWRKY24 and AhTWRKY106 TFs regulate differentially expressed genes involved in the response to drought stress.The AhTWRKY24 and AhTWRKY106 TFs can specifically regulate downstream genes,and they nearly equal the numbers of downstream genes from the two A.hypogaea cv.Tifrunner subgenomes.These results provide a theoretical basis to study the functions and regulatory networks of AhTWRKY24 and AhTWRKY106 TFs.

Tcf7l1 promotes transcription of Kruppel-like factor 4 during Xenopus embryogenesis

Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.

Important Roles of Transcription Factors in Regulating Seed Oil Biosynthesis to Increase Plant Storage Lipid Content

In this article, the biosynthetic pathways of storage oil accumulation in oilseed plants were briefly introduced, and the transcription factors, such as B3 do- main supeffamily genes, lecl gene, wril gene etc., and their important role in oil accumulation regulation was mainly elucidated. Overexpession of transcription factors as feasible ways of genetic manipulation to increase oJl content in oilseed crops are promising in a long-term perspective.

A homeodomain-leucine zipper I transcription factor, MeHDZ14,regulates internode elongation and leaf rolling in cassava(Manihot esculenta Crantz)

Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-Omethyltransferase 1(MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.

MicroRNA-146a Promotes Embryonic Stem Cell Differentiation towards Vascular Smooth Muscle Cells through Regulation of Kruppel-like Factor 4

Objective Vascular smooth muscle cell(VSMC)differentiation from stem cells is one source of the increasing number of VSMCs that are involved in vascular remodeling-related diseases such as hypertension,atherosclerosis,and restenosis.MicroRNA-146a(miR-146a)has been proven to be involved in cell proliferation,migration,and tumor metabolism.However,little is known about the functional role of miR-146a in VSMC differentiation from embryonic stem cells(ESCs).This study aimed to determine the role of miR-146a in VSMC differentiation from ESCs.Methods Mouse ESCs were differentiated into VSMCs,and the cell extracts were analyzed by Western blotting and RT-qPCR.In addition,luciferase reporter assays using ESCs transfected with miR-146a/mimic and plasmids were performed.Finally,C57BL/6J female mice were injected with mimic or miR-146a-overexpressing ESCs,and immunohistochemistry,Western blotting,and RT-qPCR assays were carried out on tissue samples from these mice.Results miR-146a was significantly upregulated during VSMC differentiation,accompanied with the VSMC-specific marker genes smooth muscle-alpha-actin(SMαA),smooth muscle 22(SM22),smooth muscle myosin heavy chain(SMMHC),and h1-calponin.Furthermore,overexpression of miR-146a enhanced the differentiation process in vitro and in vivo.Concurrently,the expression of Kruppel-like factor 4(KLF4),predicted as one of the top targets of miR-146a,was sharply decreased in miR-146a-overexpressing ESCs.Importantly,inhibiting KLF4 expression enhanced the VSMC-specific gene expression induced by miR-146a overexpression in differentiating ESCs.In addition,miR-146a upregulated the mRNA expression levels and transcriptional activity of VSMC differentiation-related transcription factors,including serum response factor(SRF)and myocyte enhancer factor 2c(MEF-2c).Conclusion Our data support that miR-146a promotes ESC-VSMC differentiation through regulating KLF4 and modulating the transcription factor activity of VSMCs.

Cone-rod homeobox transcriptionally activates TCF7 to promote the proliferation of retinal pigment epithelial and retinoblastoma cells in vitro

AIM:To investigate the proliferation regulatory effect of cone-rod homeobox(CRX)in retinal pigment epithelium(RPE)and retinoblastoma(RB)cells to explore the potential application and side effect(oncogenic potential)of CRXbased gene therapy in RPE-based retinopathies.METHODS:Adult human retinal pigment epithelial(ARPE)-19 and human retinal pigment epithelial(RPE)-1 cells and Y79 RB cell were used in the study.Genetic manipulation was performed by lentivirus-based technology.The cell proliferation was determined by a CellTiter-Glo Reagent.The mRNA and protein levels were determined by quantitative real-time polymerase chain reaction(qPCR)and Western blot assay.The transcriptional activity of the promoter was determined by luciferase reporter gene assay.The bindings between CRX and transcription factor 7(TCF7)promoter as well as TCF7 and the promoters of TCF7 target genes were examined by chromatin immunoprecipitation(ChIP)assay.The transcription of the TCF7 was determined by a modified nuclear run-on assay.RESULTS:CRX overexpression and knockdown significantly increased(n=3,P<0.05 in all the cells)and decreased(n=3,P<0.01 in all the cells)the proliferation of RPE and RB cells.CRX overexpression and knockdown significantly increased and deceased the mRNA levels of Wnt signaling target genes[including MYC proto-oncogene(MYC),JUN,FOS like 1(FOSL1),CCND1,cyclin D2(CCND2),cyclin D3(CCND3),cellular communication network factor 4(CCN4),peroxisome proliferator activated receptor delta(PPARD),and matrix metallopeptidase 7(MMP7)]and the luciferase activity driven by the Wnt signaling transcription factor(TCF7).TCF7 overexpression and knockdown significantly increased and decreased the proliferation of RPE and RB cells and depletion of TCF7 significantly abolished the stimulatory effect of CRX on the proliferation of RPE and RB cells.CRX overexpression and knockdown significantly increased and decreased the mRNA level of TCF7 and the promoter of TCF7 was significantly immunoprecipitated by CRX antibody.CONCLUSION:CRX transcriptionally activates TCF7 to promote the proliferation of RPE and RB cells in vitro.CRX is a potential target for RPE-based regenerative medicine.The potential risk of this strategy,tumorigenic potential,should be considered.

The molecular mechanism of WRINKLED1 transcription factor regulating oil accumulation in developing seeds of castor bean

The transcription factor WRINKLED1(WRI1),a member of AP2 gene family that contain typical AP2 domains,has been considered as a master regulator regulating oil biosynthesis in oilseeds.However,the regulatory mechanism of RcWRI1 in regulating oil accumulation during seed development has not been clearly addressed.Castor bean(Ricinus communis)is one of the most important non-edible oil crops and its seed oils are rich in hydroxy fatty acids,widely applied in industry.In this study,based on castor bean reference genome,three RcWRIs genes(RcWRI1,RcWRI2 and RcWRI3)were identified and the expressed association of RcWRI1 with oil accumulation were determined.Heterologous transformation of RcWRI1 significantly increased oil content in tobacco leaf,confirming that RcWRI1 activate lipid biosynthesis pathway.Using DNA Affinity Purification sequencing(DAP-seq)technology,we confirmed RcWRI1 binding with Transcription Start Site of genes and identified 7961 WRI1-binding candidate genes.Functionally,these identified genes were mainly involved in diverse metabolism pathways(including lipid biosynthesis).Three cis-elements AW-box([CnTnG](n)7[CG])and AW-boxes like([GnAnC](n)6[GC]/[GnAnC](n)7[G])bound with RcWRI1 were identified.Co-expression network analysis of RcWRI1 further found that RcWRI1 might be widely involved in biosynthesis of storage materials during seed development.In particular,yeast one hybrid experiments found that both AP2 domains within RcWRI1 were required in binding targeted genes.These results not only provide new evidence to understand the regulatory mechanism of RcWRI1 in regulation of oil accumulation during castor bean seed development,but also give candidate gene resource for subsequent genetic improvement toward increasing oil content in oilseed crops.

The R2R3-MYB transcription factor GaPC controls petal coloration in cotton

Although a few cases of genetic epistasis in plants have been reported, the combined analysis of genetically phenotypic segregation and the related molecular mechanism remains rarely studied. Here, we have identified a gene(named GaPC) controlling petal coloration in Gossypium arboreum and following a heritable recessive epistatic genetic model. Petal coloration is controlled by a single dominant gene,GaPC. A loss-of-function mutation of GaPC leads to a recessive gene Gapc that masks the phenotype of other color genes and shows recessive epistatic interactions. Map-based cloning showed that GaPC encodes an R2R3-MYB transcription factor. A 4814-bp long terminal repeat retrotransposon insertion at the second exon led to GaPC loss of function and disabled petal coloration. GaPC controlled petal coloration by regulating the anthocyanin and flavone biosynthesis pathways. Expression of core genes in the phenylpropanoid and anthocyanin pathways was higher in colored than in white petals. Petal color was conferred by flavonoids and anthocyanins, with red and yellow petals rich in anthocyanin and flavonol glycosides, respectively. This study provides new insight on molecular mechanism of recessive epistasis,also has potential breeding value by engineering GaPC to develop colored petals or fibers for multifunctional utilization of cotton.