Polymorphism of Intron 14 of Porcine CACNA2D1 Gene and Effects on Muscular pH_(45)

[ Objective] To detect polymorphism of intron 14 of porcine CACNA2Dt gene and thus provide conditions for the marker-assisted selec- tion of pork quality traits. [Method] The polymorphism of the exon 14 and intron 14 of porcine CACNA2D1 gene was detected in six breeds by PCR- SSCP. The genetic effects of different genotypes on the pH45 value of eye muscle and ham joint muscle were also analyzed. I-Result] There were three kinds of genotypes, namely, AA, AG and GG, in the intron 14 of porcine CACNA2 DI gene. The polymorphic locus （ G --~ A） was at the 1 145 nt of the sequence （GenBank Accepted No. FJ156361 ）. The results of X2 test showed that the distribution of these three kinds of genotypes was significantly different in the six breeds （P〈0.05）. The pH45 values of eye muscle and ham joint muscle were significantly different between geno- type AA and genotype AG of pigs in F2 generation from the Jianhua x Pietrain resource family （ P 〈 0.05）. [Conclusion ] The polymorphism of the in- tron 14 of porcine CACNA2D1 gene has effects on the pH45 values of eye muscle and ham joint muscle.

Retinoic acid inhibits white adipogenesis by disrupting GADD45A-mediated Zfp423 DNA demethylation

Retinoic acid （RA）, a bioactive metaboUte of vitamin A, is a critical mediator of cell differentiation. RA blocks adipogenesis, but mechanisms remain to be established. ZFP423 is a key transcription factor maintaining white adipose identity. We found that RA inhibits Zfp423 expression and adipogenesis via blocking DNA demethylation in the promoter of Zfp423, a process mediated by growth arrest and DNA-damage-inducible protein alpha （GADD45A）. RA induces the partnering between retinoic acid receptor （PAR） and tumor suppressor inhibitor of growth protein 1 （ING1）, which prevents the formation of GADD45A and ING1 complex necessary for locus-specific Zfp423 DNA demethylation. In vivo, vitamin A supplementation prevents obesity, downregulates Godd45a expression, and reduces GADD45A binding and DNA demethylation in the Zfp423 promoter. Inhibition of Zfp423 expres- sion due to PA contributes to the enhanced brown adipogenesis. In summary, PA inhibits white adipogenesis by inducing PAR and ING1 interaction and inhibiting Godd45a expression, which prevents GADD45A-mediated DNA demethylation.

The histone deacetylase inhibitor trichostatin A induces cell cycle arrest and rapid upregulation of gadd45β in LS174T human colon cancer cells

Histone deacetylase (HDAC) inhibitors are considered as promising therapeutic agents against several malignant diseases because they inhibit cancer cell proliferation. The stress sensor genes of the growth arrest and DNA damage-inducible protein (gadd45) family exhibit disordered expression in several types of malignant diseases and are thus a novel target for cancer therapy. However, there have been only few investigations of whether HDAC inhibitors affect the expression of gadd45 genes. We examined the effects of a HDAC inhibitor, trichostatin A (TSA), on the time-dependent expression of gadd45 genes in the human colon cancer cell line LS174T. Addition of TSA to LS174T cells induced inhibition of cell proliferation by arresting the cell cycle. We found that TSA treatment of LS174T cells induced rapid upregulation of gadd45β mRNA expression within 15 min, reaching a peak level at 3 h. Although the time-dependent expression pattern of gadd45β mRNA was similar to that of gadd45β mRNA, the peak level of gadd45β was lower than that of gadd45β. TSA treatment also upregulated the mRNA level of p21Waf1/Cip1, a prolif- eration inhibitor, after 3 h, but downregulated the mRNA levels of cyclin D1, a proliferation inducer, after 3 h, and of c-Myc after 1 h. TSA treatment induced a certain level of apoptosis, but the mRNA level of p53, a potent apoptosis inducer, was down-regulated after 3 h. These results suggest that the up-regulation of p21Waf1/Cip1 and apoptosis was independent of p53 and that the early upregulation of gadd45β gene, which precedes the upregulation of p21Waf1/Cip1 and the downregulation of cyclin D1, are important in TSA-treated LS174T cells.

The ethanol response gene Cab45 can modulate the impairment elicited by ethanol and ultraviolet in PC12 cells

High consumption of ethanolic beverages facilitates neurodegeneration, but the mechanism of this process still remained elusive. Suppression subtractive hybridization （SSH） is a technique for detection of rare transcripts. With SSH approach, we identified one ethanol response gene Cab45, which was down-regulated by ethanol with time-dependent manner in B104 cells. The full-length sequence of Cab45 gene was obtained by 5＇-RACE （5＇Rapid Amplification of cDNA Ends） for the first time in rat. Based on the sequence of deduced amino acid of rat Cab45, the alignment was conducted with its counterparts in different species and displayed a high conservation. Using different tissues in rat and cell lines, Cab45 was characterized by a ubiquitous expression and differentiation dependent down-regulation. Given that ethanol facilitates some cell differentiation, we hypothesize that Cab45 is involved in ethanol-mediated differentiation. With transient transfection, the function of Cab45 was investigated by up-regulation and down-regulation in PC12 cells. Ethanol treatment and UV exposure were conducted subsequently and cell proliferations were detected by MTT （Methyl Thiazolyl Tetrazolium） approach. It revealed that the up-regulation of Cab45 modulated the impairment elicited by ethanol and UV in transfected cells. As a member of new calcium binding protein family, the exact role of Cab45 still remains unclear.

Molecular Markers for Leaf Rust Resistance Gene Lr45 in Wheat Based on AFLP Analysis

Amplified fragment length polymorphism （AFLP） analysis was carried out in Thatcher, near isogenic lines （NILs） canting different genes conferring resistance against wheat leaf rust, and TcLr45 × Thatcher F2 progenies were used to develop markers for Lr45 gene. Sixty AFLP primer combinations were screened and most of them provided clear amplification products, 31 primer combinations displayed polymorphism of TcLr45 in 23 NILs. Two AFLP markers closely linked to the gene Lr45 were acquired： P-AGG/M-GAG261bp, which was found closely linked to the Lr45 locus at a distance of 0.6 cM on one side, and P-ACA/M-GGT105bp, which was found at a distance of 1.3 cM on the other side. The specific hands were cloned and subsequently sequenced. The 261-bp fragment produced by P-AGG/M-GAG showed 86% similarity with the sequence of Vulgate Hort I gene; the 105-bp fragment produced by P-ACA/M-GGT showed 96% similarity with the phosphatidylserine decarboxylase gene of the Triticum monococcum. Both included an open reading frame （ORF）.

Immunization with autologous T cells enhances in vivo anti-tumor immune responses accompanied by up-regulation of GADD45β

Immunization with inactivated autoreactive T cells may induce idiotype anti-idiotypic reactions to deplete autoreactive T cells, which are involved in autoimmune diseases. However, it is unknown whether attenuated activated healthy autologous T-cell immunization could increase anti-tumor immune responses. To this end, C57B1/6 mice were immunized with attenuated activated autologous T cells. The splenocytes from immunized mice showed a higher proliferative ability than that from naive mice. The special phenotype analysis showed that there were more CD8+ T cells and CD62L+ T cells in immunized mice after 24 h of culture with 10% fetal calf serum complete medium in vitro (P〈0.01). These results demonstrated that this immunization may activate T cells in vivo. Furthermore, the splenocytes from immunized mice revealed resistance to activation-induced cell death (AICD) in vitro. To further study the relative genes that are responsible for the higher proliferation and resistance to AICD, the expression of Fas/Fas ligand (FasL) and GADD4513 was measured by real-time PCR. The results indicated that GADD45β transcription was higher in the splenocytes from immunized mice than that in the naive mice. In addition, the Fas expression showed a parallel higher, but FasL did not change obviously. To investigate the biologic functions induced by immunization in vivo, a tumor model was established by EL-4 tumor cell inoculation in C57/B1 mice. Mice receiving autologous T-cell immunization had significantly inhibited tumor growth in vivo (P〈0.01). This study implicated that immunization with attenuated activated autologous T cells enhances anti-tumor immune responses that participate in tumor growth inhibition.

Identification of differentially expressed genes after partial rat liver ischemia/reperfusion by suppression subtractive hybridization

AIM: To identify potential diagnostic target genes in early reperfusion periods following warm liver ischemia before irreversible liver damage occurs. METHODS: We used two strategies (SSH suppression subtractive hybridization and hybridization of cDNA arrays) to determine early changes in gene expression profiles in a rat model of partial WI/R, comparing postischemic and adjacent nonischemic liver lobes. Differential gene expression was verified (WI/R; 1 h/2 h) and analyzed in more detail after warm ischemia (1 h) in a reperfusion time kinetics (0, 1, 2 and 6 h) and compared to untreated livers by Northern blot hybridizations. Protein expression was examined on Western blots and by immunohistochemistry for four differentially expressed target genes (Hsp70, Hsp27, Gadd45a and IL-1rI). RESULTS: Thirty-two individual WI/R target genes showing altered RNA levels after confirmation by Northern blot analyzes were identified. Among them, six functionally uncharacteristic expressed sequences and 26 known genes (12 induced in postischemic liver lobes, 14 with higher transcriptional expression in adjacent nonischemic liver lobes). Functional categories of the verified marker genes indicate on the one hand cellular stress and tissue damage but otherwise activation of protective cellular reactions (AP-1 transcription factors, apoptosis related genes, heat shock genes). In order to assign the transcriptional status to the biological relevant protein level we demonstrated that Hsp70, Hsp27, Gadd45a and IL-1rI were clearly up-regulated comparing postischemic and untreated rat livers, suggesting their involvement in the WI/R context. CONCLUSION: This study unveils a WI/R response gene set that will help to explore molecular pathways involved in the tissue damage after WI/R. In addition, these genes especially Hsp70 and Gadd45a might represent promising new candidates indicating WI/R liver damage.

New role and molecular mechanism of Gadd45a in hepatic fibrosis

AIM: To investigate the role of Gadd45a in hepatic fibrosis and the transforming growth factor (TGF)-beta/ Smad signaling pathway. METHODS: Wild-type male BALB/c mice were treated with CCl4 to induce a model of chronic liver injury. Hepatic stellate cells (HSCs) were isolated from the liver of BALB/c mice and were treated with small interfering RNAs (siRNAs) targeting Gadd45a or the pcDNA3.1-Gadd45a recombinant plasmid. Cellular alpha-smooth muscle actin (alpha-SMA), beta-actin, type I collagen, phospho-Smad2, phospho-Smad3, Smad2, Smad3, and Smad4 were detected by Western blots. The mRNA levels of alpha-SMA, beta-actin, and type I collagen were determined by quantitative real-time (qRT)-PCR analyses. Reactive oxygen species production was monitored by flow cytometry using 2,7-dichlorodihydrofluorescein diacetate. Gadd45a, Gadd45b, anti-Gadd45g, type I collagen, and SMA local expression in liver tissue were measured by histologic and immunohistochemical analyses. RESULTS: Significant downregulation of Gadd45a, but not Gadd45b or Gadd45g, accompanied by activation of the TGF-beta/Smad signaling pathways was detected in fibrotic liver tissues of mice and isolated HSCs with chronic liver injury induced by CCl4 treatment. Overexpression of Gadd45a reduced the expression of extracellular matrix proteins and alpha-SMA in HSCs, whereas transient knockdown of Gadd45a with siRNA reversed this process. Gadd45a inhibited the activity of a plasminogen activator inhibitor-1 promoter construct and (CAGA)(9) MLP-Luc, an artificial Smad3/4-specific reporter, as well as reduced the phosphorylation and nuclear translocation of Smad3. Gadd45a showed protective effects by scavenging reactive oxygen species and upregulating antioxidant enzymes. CONCLUSION: Gadd45a may counteract hepatic fibrosis by regulating the activation of HSCs via the inhibition of TGF-beta/Smad signaling.

Correlation of LRIG1 and Gadd45g expression in pituitary tumor with the autophagy, apoptosis and invasion of tumor cells

Objective: To study the correlation of leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) and growth arrest and dna damage 45g (Gadd45g) expression in pituitary tumor with the autophagy, apoptosis and invasion of tumor cells. Methods: Patients with pituitary tumor who underwent surgical resection in our hospital between June 2014 and December 2017 were selected, and the invasive pituitary tumor tissues and noninvasive pituitary tumor tissues were collected;patients who underwent surgery for craniocerebral trauma in our hospital during the same period were selected as the control group, and normal brain tissues were collected;the mRNA expression levels of LRIG1, Gadd45g as well as autophagy, apoptosis and invasion genes in tissue samples were measured. Results: LRIG1, Gadd45g, Beclin1, LC3-II, Bax, NKG2D and E-cadherin mRNA expression in invasive pituitary tumor and noninvasive pituitary tumor tissues were significantly lower than those in normal brain tissues whereas PTTG1, c-Myc, Gal-3, Bcl-2, EphA2, HSP27, MMP14 and VEGF mRNA expression were significantly higher than those in normal brain tissues, and LRIG1, Gadd45g, Beclin1, LC3-II, Bax, NKG2D and E-cadherin mRNA expression in invasive pituitary tumor tissues were significantly lower than those in noninvasive pituitary tumor tissues whereas PTTG1, c-Myc, Gal-3, Bcl-2, EphA2, HSP27, MMP14 and VEGF mRNA expression were significantly higher than those in noninvasive pituitary tumor tissues;LRIG1 and Gadd45g mRNA expression were positively correlated with Beclin1, LC3-II, Bax, NKG2D and E-cadherin mRNA expression, and negatively correlated with PTTG1, c-Myc, Gal-3, Bcl-2, EphA2, HSP27, MMP14 and VEGF mRNA expression. Conclusion: The low expression of LRIG1 and Gadd45g in pituitary tumor can inhibit the autophagy and apoptosis of tumor cells and promote the invasion of tumor cells.

青蒿琥酯通过调控GADD45A、NACC1的表达抑制肝癌细胞的作用

目的阐明青蒿琥酯(artesunate,ART)在肝细胞癌(hepatocellular carcinoma,HCC)病理进程中对肿瘤细胞的作用及潜在的机制。方法用含不同浓度ART的培养基处理两种HCC细胞系MHCC-97H、HCC-LM3,以0 mg·L-1 ART处理的细胞作为对照组,对比ART对HCC的作用。采用MTT和克隆形成实验测定ART对HCC细胞生长能力的影响;划痕实验和Transwell实验分别检测ART对HCC细胞迁移和侵袭能力的影响;流式细胞术验证ART对HCC细胞凋亡和细胞周期变化的影响;通过转录组测序分析以及qRT-PCR验证关键基因的表达情况探究ART在HCC细胞中的可能作用机制。结果与对照组相比,ART处理后的肿瘤细胞增殖、迁移、侵袭能力明显降低(P<0.01),而细胞凋亡率明显上升,且G_(2)/M期细胞比例明显增高,提示肿瘤细胞被阻滞于该期。使用RNA测序数据进行转录组学分析,确定生长停滞与DNA损伤诱导蛋白45A(growth arrest and DNA damage inducible alpha,GADD45A)是ART的潜在作用靶点,并且提示,ART可通过上调GADD45A的表达进而诱导细胞凋亡和细胞周期阻滞。此外,生信分析结果提示,GADD45A与其上游转录因子伏隔核相关蛋白1(nucleus accumbens associated 1,NACC1)有蛋白互作现象,并且经ART处理后,GADD45A与NACC1的mRNA水平和蛋白水平均发生明显变化。结论ART可能通过影响GADD45A及其潜在上游NACC1基因的表达抑制HCC的发生发展。通过探究ART作用于HCC的功能影响及发生机制,为临床治疗肝癌提供新药物、新方向和新思路。

Bavachin induces apoptosis in colorectal cancer cells through Gadd45a via the MAPK signaling pathway

Bavachin is a dihydroflavonoid compound isolated from Psoralea corylifolia,and exhibits anti-bacterial,anti-inflammatory,anti-tumor and lipid-lowering activities.Recent attention has gradually drawn on bavachin-induced apoptosis in many human cancer cell lines.However,the anti-cancer effects and related mechanisms in colorectal cancer remain unknown.Here,we investigated the effects of bavachin on colorectal cancer in vivo and in vitro.The results showed that bavachin inhibited the proliferation of human colorectal cancer cells and induce apoptosis.These changes were mediated by activating the MAPK signaling pathway,which significantly up-regulated the expression of Gadd45a.Furthermore,Gadd45a silencing obviously attenuated bavachin-mediated cell apoptosis.Inhibition of the MAPK signaling pathway by JNK/ERK/p38 inhibitors also weakened the up-regulation of Gadd45a by bavachin.The anticancer effect of bavachin was also validated using a mouse xenograft model of human colorectal cancer.In conclusion,these findings suggest that bavachin induces the apoptosis of colorectal cancer cells through activating the MAPK signaling pathway.

异丙酚通过miR-133a-3p/FTL轴调控GADD45A/JNK通路影响胃癌细胞增殖、迁移及凋亡

目的:探讨异丙酚是否通过miR-133a-3p/FTL轴调控GADD45A/JNK通路影响胃癌细胞的增殖、迁移及凋亡。方法:将胃癌MKN-28细胞系分为磷酸盐缓冲液(PBS)组、异丙酚组、miR-NC组、miR-133a-3p mimics组、anti-miR-NC组、anti-miR-133a-3p组、si-NC组、si-FTL组、异丙酚+anti-miR-NC+si-NC组、PBS+anti-miR-NC+si-NC组、异丙酚+anti-miR-133a-3p+si-NC组、异丙酚+anti-miR-133a-3p+si-FTL组。应用RT-qPCR检测miR-133a-3p和铁蛋白轻链(FTL)mRNA的表达水平;应用MTT法与克隆形成实验测细胞增殖;应用流式细胞术、蛋白质印迹法分别检测细胞凋亡及蛋白表达水平;应用双荧光素酶报告实验检测miR-133a-3p与FTL的靶向关系;应用划痕实验与Transwell侵袭实验检测细胞迁移和侵袭。结果:与PBS组比较,异丙酚组细胞活性、划痕愈合率、细胞克隆形成数、迁移、侵袭细胞数均减少(P<0.05);细胞凋亡率、p53、Bcl-2相关X蛋白(Bax)、miR-133a-3p、GADD45A及p-JNK蛋白表达水平均升高(P<0.05),FTL表达水平降低(P<0.05)。双荧光素酶实验结果显示,miR-133a-3p靶向调控FTL。敲低FTL或过表达miR-133a-3p后,细胞凋亡率升高,细胞活性、划痕愈合率、细胞克隆形成数、迁移和侵袭细胞数降低;细胞中GADD45A、p-JNK、p53、Bax表达水平升高(P<0.05)。敲低FTL逆转了使用异丙酚及抑制miR-133a-3p表达对GADD45A/JNK信号通路以及MKN-28细胞恶性生物学行为的影响。结论:异丙酚可能通过miR-133a-3p/FTL轴调控GADD45A/JNK通路继而抑制胃癌细胞增殖、迁移,并促进细胞凋亡。

氟氯氰菊酯通过GADD45B介导JNK/p38MAPK通路对大鼠肾脏损伤的影响

目的 探讨氟氯氰菊酯暴露通过影响生长停滞和DNA损伤诱导β(GADD45B)水平并介导JNK/p38MAPK通路对大鼠肾脏损伤的影响。方法 将40只SPF级Wistar雄性大鼠按随机数表法分为4组,即对照组、氟氯氰菊酯低剂量组、中剂量组、高剂量组,每组10只。隔天灌胃连续染毒28 d,取肾脏组织称量后计算脏器系数。HE染色光镜下观察大鼠肾脏组织病理形态变化;透射电镜观察肾脏细胞超微结构变化;应用试剂盒检测肾脏组织中氧化损伤指标超氧化物歧化酶(SOD)、丙二醛(MDA)含量变化;应用Western blot、qPCR检测GADD45B、p38MAPK、p-p38MAPK、JNK、p-JNK mRNA及蛋白表达水平变化。结果 与对照组相比,氟氯氰菊酯染毒大鼠体质量增长、肾脏质量和脏器系数的差异均无统计学意义(P均>0.05);HE染色结果显示:与对照组相比,随着氟氯氰菊酯染毒剂量的增加,肾小管肿胀越发明显,肾小管上皮细胞大量脱落,肾小球萎缩。透射电镜结果显示:与对照组相比,随着氟氯氰菊酯染毒剂量的增加,基底膜逐渐增厚,线粒体和内质网出现不同程度损伤。与对照组比较,低、中、高剂量组MDA含量均升高(P均<0.05)、SOD活力均降低(P均<0.05)。与对照组相比,氟氯氰菊酯低、中、高剂量组中GADD45B的mRNA表达水平均升高(P均<0.05);JNK和p38MAPK的mRNA表达水平均降低(P均<0.05)。Western blot结果显示,与对照组比较,氟氯氰菊酯低、中、高剂量组中GADD45B、p-JNK、p-p38的蛋白表达水平均升高(P均<0.05);JNK和p38的蛋白表达水平均降低(P均<0.05)。结论 在氟氯氰菊酯致大鼠肾脏损伤中,GADD45B可通过激活JNK/p38MAPK通路诱导大鼠肾脏损伤。

GADD45A通过端粒替代延长途径调控骨肉瘤细胞增殖

目的:探讨GADD45A对骨肉瘤细胞的增殖和端粒调控功能。方法:应用siRNA和shRNA处理骨肉瘤细胞U2OS,观察骨肉瘤细胞增殖、端粒功能和端粒延长替代途径的变化。qPCR检测GADD45A敲低后mRNA水平。CCK-8实验和克隆形成实验检测骨肉瘤细胞增殖情况。细胞中期分裂相-荧光原位杂交实验检测端粒功能变化。免疫荧光-荧光原位杂交实验和C-circle实验检测端粒损伤情况和端粒延长替代途径相关表型。结果:qPCR结果表明,siRNA敲低GADD45A后mRNA水平降低(t=25.96,P<0.0001);shGADD45A-1和shGADD45A-2 GADD45A的mRNA水平降低(t=21.12、18.37,均P<0.0001)。对应的CCK-8(t=5.051、6.192、3.775、14.86、22.93、3.013、14.61、20.93,均P<0.05)和克隆形成实验(t=46.68、23.73、24.98,均P<0.0001)结果表明,敲低GADD45A抑制了骨肉瘤细胞增殖。细胞中期分裂相-荧光原位杂交实验结果显示,GADD45A缺失会加重端粒多信号(t=24.04、7.243、27.93,均P<0.01)和端粒信号缺失现象(t=8.222、16.61、6.781,均P<0.01)。免疫荧光-荧光原位杂交实验结果表明,siRNA敲低GADD45A后H2AX组蛋白变体和早幼粒细胞白血病体与端粒的共定位增加(t=19.16、10.65,均P<0.0001);shGADD45A-1、shGADD45A-2也证实了H2AX组蛋白变体和早幼粒细胞白血病体与端粒共定位的比例升高(t=14.71、24.03、16.69、18.10,均P<0.0001)。C-circle实验结果表明,siRNA敲低GADD45A以及shGADD45A-1和shGADD45A-2两细胞系中染色体外端粒DNA环C-circle水平升高(t=41.27、14.06、4.539,均P<0.05)。结论:GADD45A调控端粒延长替代途径、保护端粒功能并促进骨肉瘤细胞增殖。

A novel erythroid differentiation related gene EDRF1 upregulating globin gene expression in HEL cells

OBJECTIVE: To further characterize the differentiation inducing properties of EDRF1 and demonstrate its functional pathway involved in regulation of globin gene expression. METHODS: By transfecting EDRF1 sense and antisense constructs into HEL cells, we identified the expression of globin and erythropoietin receptor genes by Northern blot analysis. RT-PCR and EMSA (electrophoresis mobility shift assay) were performed to monitor the expression and DNA-binding activity of erythroid specific transcription factors GATA-1 and NF-E2. RESULTS: It was shown that when EDRF1 was overexpressed, production of alpha-globin increased. In antisense EDRF1, overexpression of HEL cells, significant loss of alpha-, gamma-globin mRNA synthesis was observed. The transcription of endogenous GATA-1 and NF-E2 mRNA expression were maintained at the same levels compared with control experiments. However, the transcription activity of GATA-1 was severely impaired. Expression of erythropoietin receptor gene was not influenced by EDRF1 gene overexpression. CONCLUSION: The results suggested that EDRF1 regulated alpha- and gamma-globin gene synthesis by modulating DNA-binding activity of GATA-1 transcription factor.

^(60)Coγ射线照射淋巴细胞诱导PIG3和GADD45基因mRNA变化

用^(60)Coγ射线照射正常人外周血永生化淋巴细胞系后,初步分析受照细胞中PIG3和GADD45基因mRNA表达水平的改变状况,并探讨上述基因作为辐射生物剂量计的可能性及意义。用^(60)Coγ射线照射淋巴细胞,采用不同剂量(0～10Gy)照射和照射后不同时间点(0～72h)收集细胞,抽提mRNA,用Real-time PCR检测细胞中PIG3和GADD45基因mRNA表达水平的变化。结果表明,正常人外周血永生化淋巴细胞系中PIG3和GADD45基因mRNA表达水平随照射剂量的增高而增加,并呈现出剂量效应关系。5Gy剂量^(60)Coγ射线照射后,淋巴细胞中PIG3和GADD45基因mRNA表达水平随时间的推移不断增高,在8h时均达到最高,随后开始降低。PIG3和GADD45基因对辐射均较敏感,其表达具有良好的剂量效应和时间效应关系,但相比而言,PIG3的表达随照射剂量和照射后时间的变化更加显著,更有潜力作为生物剂量计以满足实际需要。

电离辐射对人外周血淋巴细胞GADD45基因表达的影响

观察生长抑制和DNA损伤基因45(Growth arrest and DNA damage gene 45,GADD45)X射线照射后表达的改变,并研究其与照射剂量之间的关系。外周血给予0-5 GyX线照射后分离出单个核细胞并培养,在不同时间点上用反转录聚合酶链反应(Reverse transcriptase-Polymerase clain reaction,RT-PCR)的方法测定 GADD45基因的相对表达量,分析该基因的剂量、效应关系。照射后GADD45基因在转录水平表达呈剂量依赖性增加,照射后4h达峰值,以后开始下降,但在24h仍未恢复到初始水平。

海风藤酮对老龄大鼠局灶性脑缺血DNA损伤修复相关基因GADD45表达的影响

目的:观察老龄大鼠局灶性脑缺血后DNA损伤修复相关基因GADD45表达的规律,探讨海风藤酮对神经细胞凋亡及GADD45表达的影响。方法:采用26月龄Wistar大鼠,经光化学诱导局灶性脑缺血后应用海风藤酮进行干预,观察不同时间和空间状态下GADD45蛋白表达的改变,同时运用TUNEL染色观察神经细胞的凋亡现象。结果:缺血4h组,在缺血中心区可见少许GADD45反应阳性细胞,而缺血周边区GADD45反应阳性细胞大量表达,较对照组差异有统计学意义(P<0.05)。缺血24h组,周边区GADD45表达较缺血4h有所降低,但仍高于假手术组(P<0.05),至缺血5d时,周边区GADD45表达较假手术组无明显差异。海风藤酮治疗组,缺血周边区TUNEL阳性细胞数较假手术组增多(P<0.05),但较对照组减少(P<0.05),而GADD45表达阳性细胞数较对照组增多(P<0.05),与假手术组比较增多(P<0.01)。结论:海风藤酮可有效保护缺血神经细胞,同时可以上调DNA修复基因GADD45的表达,减小DNA损伤的程度。

Gadd45介导抑癌基因BRCA1诱导的G_2/M期阻滞

背景与目的:目前已经肯定,抑癌基因BRCA1是细胞周期监测点调控的重要因子,但BRCA1在细胞周期阻滞中的作用机制尚不完全清楚。本研究的目的是探讨Gadd45在BRCA1诱导的细胞周期阻滞中所起的作用。方法:应用转染、流式细胞仪细胞筛选(分选)、Westernblot检测分析BRCA1诱导Gadd45的表达;利用CAT酶活性测定的方法检测外源BRCA1对Gadd45启动子所起作用;以流式细胞周期分析方法检测反义Gadd45转染对BRCA1诱导的细胞G2/M期阻滞的影响;采用细胞生长集落形成分析反义Gadd45转染HeLa、HCT116细胞在BRCA1诱导的细胞生长抑制过程所起的作用。结果:外源转染BRCA1可诱导Gadd45蛋白的表达;BRCA1激活Gadd45启动子的转录;反义Gadd45可显著阻遏BRCA1诱导细胞G2/M期阻滞;反义Gadd45转染可明显降低BRCA1对HeLa、HCT116细胞集落形成的抑制作用。结论:Gadd45作为BRCA1的下游调控基因,在BRCA1诱导的细胞G2/M期阻滞过程和生长抑制中起介导作用。

Gadd45a在抑制细胞转化和肿瘤恶性进展中的作用

Gadd45a,一个受p53和BRCA1调节的生长阻滞和DNA损伤基因,在抑制细胞转化和肿瘤恶性进展中扮演重要的角色.Gadd45a可以通过抑制细胞生长以及促进DNA损伤修复等间接或者直接方式维持基因组稳定性,从而抑制细胞转化和肿瘤的恶性进展.此外,Gadd45a还可通过对一些信号传导通路的调节,参与肿瘤发生发展的抑制.