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.

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.

Isolation and Structural Analysis of DRE-Binding Transcription Factor from Maize (Zea mays L.)

Dehydration-responsive element-binding (DREB) proteins specifically binding with dehydration-responsive element (DRE) have been identified as a kind of important transcription activator of plants under drought, high salt and cold stress. The conserved amino, acid residues of Val (14th residue) and Glu (19th residue) in AP2/EREBP domain of DREB1A have been identified to be two key points in determining the binding ability of DREB gene with DRE element. Using the yeast one-hybrid system, we isolated one maize DREB gene named maDREB1 by screening cDNA library. Trans-activation experiment in yeast reporter strain demonstrated that maDREB1 protein could function as a DREB transcription factor activating target gene expression by specifically binding to the DRE cis-element. To assess the functional significance of these two residues in maDREB1, the V14 and E19 were substituted individually or doubly by Ala and Asp. Point mutation analysis showed that V14 substitution made significant loss of binding ability with DRE element, while point mutation of E19 had less effect. If the substitution happened simultaneously to these two residues, it would lead to great loss of the ability of binding with DRE element. It suggested that V14 and E19 were both important in protein-DNA interacting in maDREB1, though 14V was more essential. The copy number and expression pattern of maDREB1 was discussed.

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.

Oligodendrocyte transcription factor 1 overexpression promotes oligodendrocyte transcription factor 2 expression in the brains of neonatal rats exposed to hypoxia

To examine the expression profiles of oligodendrocyte transcription factors 1 and 2 （Oligl and Olig2） and the interaction between these two proteins, Oligl was transfected into the lateral ventricles of neonatal rats subjected to hypoxia. Immunohistochemistry demonstrated that Olig2 was expressed throughout the nuclei in the brain, and expression increased at 3 days following hypoxia and was higher than levels at 7 days following Ad5-Oligl transfection. Western blot revealed that Oligl and Olig2 expression increased in Oligl-transfected brain cells 3 days after hypoxia, but Oligl and Olig2 expression decreased at 7 days. These results indicate that Oligl overexpression enhances Olig2 expression in brain tissues of hypoxia rats.

NECK LEAF 1, a GATA type transcription factor, modulates organogenesis by regulating the expression of multiple regulatory genes during reproductive development in rice

In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.

Transcription factor PDX-1 in human colorectal adenocarcinoma:A potential tumor marker?

AIM: To examine the expression of pancreatic duodenal homeobox-1 (PDX-1) transcription factor in human colorectal cancer. METHODS: RT-PCR, Western blotting, and immuno-histochemistry were performed to determine the expression pattern of transcription factor PDX-1 in primary colorectal tumor, hepatic metastasis, and benign colon tissue from a single patient. RESULTS: The highest PDX-1 transcription levels were detected in the metastasis material. Lower levels of PDX-1 were found to be present in the primary tumor, while normal colon tissue failed to express detectable levels of PDX-1. Western blot data revealed a PDX-1 expression pattern identical to that of mRNA expression. Immunohistochemistry confirmed high metastasis PDX-1 expression, lower levels in the primary tumor, and the presence of only traces of PDX-1 in normal colon tissue. CONCLUSION: These data argue for further evaluation of PDX-1 as a biomarker for colorectal cancer.

Transcription factor-based gene therapy to treat glioblastoma through direct neuronal conversion

Objective:Glioblastoma(GBM)is the most prevalent and aggressive adult primary cancer in the central nervous system.Therapeutic approaches for GBM treatment are under intense investigation,including the use of emerging immunotherapies.Here,we propose an alternative approach to treat GBM through reprogramming proliferative GBM cells into non-proliferative neurons.Methods:Retroviruses were used to target highly proliferative human GBM cells through overexpression of neural transcription factors.Immunostaining,electrophysiological recording,and bulk RNA-seq were performed to investigate the mechanisms underlying the neuronal conversion of human GBM cells.An in vivo intracranial xenograft mouse model was used to examine the neuronal conversion of human GBM cells.Results:We report efficient neuronal conversion from human GBM cells by overexpressing single neural transcription factor Neurogenic differentiation 1(Neuro D1),Neurogenin-2(Neurog2),or Achaete-scute homolog 1(Ascl1).Subtype characterization showed that the majority of Neurog2-and Neuro D1-converted neurons were glutamatergic,while Ascl1 favored GABAergic neuron generation.The GBM cell-converted neurons not only showed pan-neuronal markers but also exhibited neuron-specific electrophysiological activities.Transcriptome analyses revealed that neuronal genes were activated in glioma cells after overexpression of neural transcription factors,and different signaling pathways were activated by different neural transcription factors.Importantly,the neuronal conversion of GBM cells was accompanied by significant inhibition of GBM cell proliferation in both in vitro and in vivo models.Conclusions:These results suggest that GBM cells can be reprogrammed into different subtypes of neurons,leading to a potential alternative approach to treat brain tumors using in vivo cell conversion technology.

Upregulation of miR-34c after silencing E2F transcription factor 1 inhibits paclitaxel combined with cisplatin resistance in gastric cancer cells

BACKGROUND MicroRNA 34c(miR-34c)has been reported to be associated with malignant types of cancer,however,it remains unknown whether miR-34c is involved in chemoresistance in gastric cancer(GC).AIM To investigate the effect of miR-34c and its upstream transcription factor E2F1 on paclitaxel combined with cisplatin resistance in GC cells.METHODS Paired GC tissues and adjacent normal tissues were randomly sampled from 74 GC patients.miR-34c and E2F1 were detected by real-time quantitative PCR(qPCR)and Western blot.In addition,the drug resistance of GC cells to paclitaxel and cisplatin was induced by concentration gradient increasing methods,and changes in miR-34c and E2F1 during this process were measured.Furthermore,E2F1 and miR-34c overexpression or underexpression vectors were constructed and transfected into drug-resistant GC cells.MTT was employed to test the sensitivity of cells to paclitaxel combined with cisplatin,qPCR was adopted to detect the expression of miR-34c,Western blot was applied to detect the expression levels of E2F1,drug resistance-related proteins and apoptosis-related proteins,and flow cytometry was used for the determination of cell apoptosis and cell cycle status.RESULTS E2F1 was overexpressed while miR-34c was underexpressed in GC.After inducing GC cells to be resistant to paclitaxel and cisplatin,E2F1 expression increased while miR-34c expression decreased.Both silencing E2F1 and overexpressing miR-34c could increase the sensitivity of drug-resistant GC cells to paclitaxel combined with cisplatin,promote cell apoptosis and inhibit cell proliferation.Among which,silencing E2F1 could reduce the expression of drug resistance-related proteins and apoptosis-related proteins,while over-expression of miR-34c could upregulate the expression of apoptosis-related proteins without affecting the expression of MDR-1,MRP and other drug resistance-related proteins.Rescue experiments demonstrated that inhibiting miR-34c could significantly weaken the sensitization of drug resistant cells,and Si E2F1 to paclitaxel combined with cisplatin.CONCLUSION E2F1 inhibits miR-34c to promote the proliferation of GC cells and enhance the resistance to paclitaxel combined with cisplatin,and silencing E2F1 is conducive to improving the efficacy of paclitaxel combined with cisplatin in GC cells.

Silencing the SLB3 transcription factor gene decreases drought stress tolerance in tomato

BRI1-EMS-SUPPRESSOR 1(BES1)transcription factor is closely associated with the brassinosteroid(BR)signaling pathway and plays an important role in plant growth and development.SLB3 is a member of BES1 transcription factor family and its expression was previously shown to increase significantly in tomato seedlings under drought stress.In the present study,we used virus-induced gene silencing(VIGS)technology to downregulate SLB3 expression to reveal the function of the SLB3 gene under drought stress further.The downregulated expression of SLB3 weakened the drought tolerance of the plants appeared earlier wilting and higher accumulation of H2 O2 and O2^–·,decreased superoxide dismutase(SOD)activity,and increased proline(PRO)and malondialdehyde(MDA)contents and peroxidase(POD)activity.Quantitative real-time PCR(qRT-PCR)analysis of BR-related genes revealed that the expression of SlCPD,SlDWARF and BIN2-related genes was significantly upregulated in SLB3-silenced seedlings under drought stress,but that the expression of TCH4-related genes was downregulated.These results showed that silencing the SLB3 gene reduced the drought resistance of tomato plants and had an impact on the BR signaling transduction which may be probably responsible for the variation in drought resistance of the tomato plants.

Transcription factor EGR-1 inhibits growth of hepatocellular carcinoma and esophageal carcinoma cell lines

AIM: The transcription factor EGR-1 (early growth response gene-1) plays an important role in cell growth, differentiation and development. It has identified that EGR-1 has significant transformation suppression activity in some neoplasms, such as fibrosarcoma, breast carcinoma. This experiment was designed to investigate the role of egr-1 in the cancerous process of hepatocellular carcinoma (HCC) and esophageal carcinoma (EC), and then to appraise the effects of EGR-1 on the growth of these tumor cells. METHODS: Firstly, the transcription and expression of egr-1 in HCC and EC, paracancerous tissues and their normal counterpart parts were detected by in situ hybridization and immunohistochemistry, with normal human breast and mouse brain tissues as positive controls. Egr-1 gene was then transfected into HCC (HHCC, SMMC7721) and EC (ECa109) cell lines in which no egr-1 transcription and expression were present. The cell growth speed, FCM cell cycle, plate clone formation and tumorigenicity in nude mice were observed and the controls were the cell lines transfected with vector only. RESULTS: Little or no egr-1 transcription and expression were detected in HCC, EC and normal liver tissues. The expression of egr-1 were found higher in hepatocellular paracancerous tissue (transcription level P=0.000; expression level P=0.143, probably because fewer in number of cases) and dysplastic tissue of esophageal cancer (transcription level P=0.000; expression level P=0.001). The growth rate of egr-1-transfected HHCC (HCC cell line) cells and ECa109 (EC cell line) cells was much slower than that of the controls. The proportion of S phase cell, clone formation and tumorigenicity were significantly lower than these of the controls' (decreased 45.5% in HHCC cells and 34.1% in ECa109 cells; 46.6% and 41.8%; 80.4% and 72.6% respectively). There were no obvious differences between SMMC7721 (HCC) egr-1-transfected cells and the controls with regard to the above items. CONCLUSION: The decreased expression of egr-1 might play a role in the dysregulation of normal growth in the cancerous process of HCC and EC. Egr-1 gene of transfected HHCC and ECa109 cells showed obvious suppression of the cell growth and malignant phenotypes, but no suppression in SMMC7721 (HCC cell line) cells.

Experimental and clinic-opathologic study on the relationship between transcription factor Egr-1 and esophageal carcinoma

AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor. METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry. RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P 【 0.01) and the average growth rate of tumor in SCID mice (35.5 +/- 7.6 vs 65.8 +/- 7.6, P 【 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 0.01). CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.

Genome-wide analysis of the B3 transcription factors reveals that RcABI3/VP1 subfamily plays important roles in seed development and oil storage in castor bean(Ricinus communis)

The B3 transcription factors(TFs)in plants play vital roles in numerous biological processes.Although B3 genes have been broadly identified in many plants,little is known about their potential functions in mediating seed development and material accumulation.Castor bean(Ricinus communis)is a non-edible oilseed crop considered an ideal model system for seed biology research.Here,we identified a total of 61 B3 genes in the castor bean genome,which can be classified into five subfamilies,including ABI3/VP1,HSI,ARF,RAV and REM.The expression profiles revealed that RcABI3/VP1 subfamily genes are significantly up-regulated in the middle and later stages of seed development,indicating that these genes may be associated with the accumulation of storage oils.Furthermore,through yeast one-hybrid and tobacco transient expression assays,we detected that ABI3/VP1 subfamily member RcLEC2 directly regulates the transcription of RcOleosin2,which encodes an oil-body structural protein.This finding suggests that RcLEC2,as a seed-specific TF,may be involved in the regulation of storage materials accumulation.This study provides novel insights into the potential roles and molecular basis of B3 family proteins in seed development and material accumulation.

GmPHR1, a Novel Homolog of the AtPHR1 Transcription Factor, Plays a Role in Plant Tolerance to Phosphate Starvation

GmPHR1 from soybean （Glycine max） was isolated and characterized. This novel homolog of the AtPHR1 transcription factor confers tolerance to inorganic phosphate （Pi）-starvation. The gene is 2 751 bp long, with an 819-bp open reading frame and ifve introns. Analysis of transcription activity in yeast revealed that the full-length GmPHR1 and its C-terminal activate the reporter genes for His, Ade and Ura, suggesting that the C-terminal peptide functions as a transcriptional activator. Quantitative real-time PCR indicated that patterns of GmPHR1 expression differed. For example, under low-Pi stress, this gene was quickly induced in the tolerant JD11 after 0.5 h, with expression then decreasing slowly before peaking at 12-24 h. By contrast, induction in the sensitive Niumaohuang （NMH） was slow, peaking at 6 h before decreasing quickly at 9 h. GmPHR1 showed sub-cellular localization in the nuclei of onion epidermal cells and Arabidopsis roots. Growth parameters in wild-type （WT） Arabidopsis plants as well as in overexpression （OE） transgenic lines were examined. Under low-Pi conditions, values for shoot, root and whole-plant dry weights, root to shoot ratios, and lengths of primary roots were signiifcantly greater in OE lines than in the WT. These data demonstrate that GmPHR1 has an important role in conferring tolerance to phosphate starvation.

Transcription factor networks involved in cell death in the dorsal root ganglia following peripheral nerve injury

The peripheral nervous system has the potential to regenerate after nerve injury owing to the intrinsic regrowth ability of neurons and the permissive microenvironment.The regenerative process involves numerous gene expression changes,in which transcription factors play a critical role.Previously,we profiled dysregulated genes in dorsal root ganglion neurons at different time points（0,3 and 9 hours,and 1,4 and 7 days） after sciatic nerve injury in rats by RNA sequencing.In the present study,we investigated differentially expressed transcription factors following nerve injury,and we identified enriched molecular and cellular functions of these transcription factors by Ingenuity Pathway Analysis.This analysis revealed the dynamic changes in the expression of transcription factors involved in cell death at different time points following sciatic nerve injury.In addition,we constructed regulatory networks of the differentially expressed transcription factors in cell death and identified some key transcription factors（such as STAT1,JUN,MYC and IRF7）.We confirmed the changes in expression of some key transcription factors（STAT1 and IRF7） by quantitative reverse transcription-polymerase chain reaction.Collectively,our analyses provide a global overview of transcription factor changes in dorsal root ganglia after sciatic nerve injury and offer insight into the regulatory transcription factor networks involved in cell death.

Myocardin-related transcription factor A cooperates with brahmarelated gene 1 to activate P-selectin transcription

Expression of P-selectin in injured or activated endothelia cells serves as a permissive step towards leukocyte recruitment and perpetuation of inflammation in the pathogenesis of atherosclerosis.P-selectin can be induced by pro-inflammatory stimuli via the transcription factor NF-κB,but the epigenetic mechanisms remain incompletely understood.Previously we reported that myocardin-related transcription factor A（MRTF-A）mediates the transactivation of a slew of adhesion molecules by oxidized low-density lipoprotein（oxLDL）,likely through a crosstalk with brahma-related gene 1（BRGl）,a chromatin remodeling protein.Here,we show that MRTF-A was both sufficient and necessary for the transactivation of P-selectin gene in endothelial cells treated with TNF-α.Depletion of MRTF-A using small interfering RNA（siRNA）abrogated the binding of BRGl on the P-selectin promoter.Overexpression of BRG1 up-regulated the activity of P-selectin promoter activity while BRGl knockdown attenuated P-selectin expression.Finally,BRGl silencing suppressed the accumulation of acetylated histone H3 and methylated histone H3K4,and altered the binding of NF-κB on the P-selectin promoter.Therefore,our data demonstrate an essential role for MRTF-A and BRGl in P-selectin transactivation in endothelial cells.

OsbZIP09,a Unique OsbZIP Transcription Factor of Rice,Promotes Rather Than Suppresses Seed Germination by Attenuating Abscisic Acid Pathway

We successfully identified a novel and unique OsbZIP transcription factor,OsbZIP09,whose mutants exhibited longer seeds and less severe pre-harvest sprouting than the wild type,but shared similar germination rate as the wild type under normal germination conditions.The expression of OsbZIP09 was induced by abscisic acid(ABA)and declined as the germination process.As a nucleus-localized transcription factor,the conserved binding motif of OsbZIP09 was identified via DNA affinity purification sequencing technique.Further evidences indicated that OsbZIP09 directly enhanced the expression of ABA catabolism gene ABA8ox1,thus reducing ABA accumulation.In addition,OsbZIP09 also directly bound to the promoter of LEA3 gene to inhibit its expression,thus further alleviating the suppressive effect of ABA on seed germination.These results demonstrated that OsbZIP09 likely functions as a brake of the ABA pathway to attenuate the inhibitory effect of ABA on rice seed germination via dual strategies.

Transcription factors specificity protein and nuclear receptor 4A1 in pancreatic cancer

Specificity protein(Sp)transcription factors(TFs)Sp1,Sp3 and Sp4,and the orphan nuclear receptor 4A1(NR4A1)are highly expressed in pancreatic tumors and Sp1 is a negative prognostic factor for pancreatic cancer patient survival.Results of knockdown and overexpression of Sp1,Sp3 and Sp4 in pancreatic and other cancer lines show that these TFs are individually pro-oncogenic factors and loss of one Sp TF is not compensated by other members.NR4A1 is also a prooncogenic factor and both NR4A1 and Sp TFs exhibit similar functions in pancreatic cancer cells and regulate cell growth,survival,migration and invasion.There is also evidence that Sp TFs and NR4A1 regulate some of the same genes including survivin,epidermal growth factor receptor,PAX3-FOXO1,α5-andα6-integrins,β1-,β3-andβ4-integrins;this is due to NR4A1 acting as a cofactor and mediating NR4A1/Sp1/4-regulated gene expression through GC-rich gene promoter sites.Several studies show that drugs targeting Sp downregulation or NR4A1 antagonists are highly effective inhibitors of Sp/NR4A1-regulated pathways and genes in pancreatic and other cancer cells,and the triterpenoid celastrol is a novel dual-acting agent that targets both Sp TFs and NR4A1.

Oligodendrocyte transcription factor 1 mRNA and protein expression in organotypic rat brain slices

Numerous studies have confirmed that oligodendrocyte transcription factor 1 （Olig-1） is vital for myelin repair. However, the effects of hypoxia and ischemia on Olig-1 expression remain unknown. In this study, Olig-1 mRNA and protein expressions were analyzed by in situ hybridization and immunohistochemistry, to determine the expression profile of Olig-1 in rat brain slices exposed to hypoxia and ischemia. Brains were obtained from 2-day-old Sprague-Dawley rats, and sections were randomly assigned to control and hypoxia/ischemia groups. Hematoxylin-eosin staining revealed karyorrhexis and karyopyknosis in cells from the hypoxia/ischemia group. Under electron microscopy, mitochondria swelling and neuropil edema were observed in the hypoxiaJischemia group. Olig-1 mRNA and protein expressions were increased at 1 day after hypoxia and ischemia treatment. These results suggest that in situ hybridization and immunohistochemistry could be used simultaneously to detect mRNA and protein expression in brain slices.

Immunolocalization of the oligodendrocyte transcription factor 1(Olig1) in brain tumors

Recent in situ hybridization studies showed that mRNA levels of OLIGl and OLIG2 transcription factors are elevatedin oligodendrogliomas.We raised polyclonal antibodies against a synthetic peptide homologous to the human tran-scription factor Oligl and studied by immunohistochemistry the expression of Oligl in 84 brain tumors and in non-neoplastic brain tissues.All oligodendrogliomas,oligoastrocytomas,and dysembryoplastic neuroepithelial tumorsshowed moderate to strong intranuclear immunoreactivity in cells morphologically identified as oligodendrocytes.