Overexpression of a TFIIIA-type zinc finger protein gene ZFP252 enhances drought and salt tolerance in rice (Oryza sativa L.)

We previously identified a salt and drought stress-responsive TFIIIA-type zinc finger protein gene ZFP252 from rice. Here we report the functional analysis of ZFP252 using gain- and loss-of-function strategies. We found that overexpression of ZFP252 in rice increased the amount of free proline and soluble sugars, elevated the expression of stress defense genes and enhanced rice tolerance to salt and drought stresses, as compared with ZFP252 antisense and non-transgenic plants. Our findings suggest that ZFP252 plays an important role in rice response to salt and drought stresses and is useful in engineering crop plants with enhanced tolerance to salt and drought stresses.     

The Aryl Hydrocarbon Receptor-interacting Protein (AIP) Is Required for Dioxin-induced Hepatotoxicity but Not for the Induction of the Cyp1a1 and Cyp1a2 Genes

The aryl hydrocarbon receptor (AHR) plays an essential role in the toxic response to environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), in the adaptive up-regulation of xenobiotic metabolizing enzymes, and in hepatic vascular development. In our model of AHR signaling, the receptor is found in a cytosolic complex with a number of molecular chaperones, including Hsp90, p23, and the aryl hydrocarbon receptor-interacting protein (AIP), also known as ARA9 and XAP2. To understand the role of AIP in adaptive and toxic aspects of AHR signaling, we generated a conditional mouse model where the Aip locus can be deleted in hepatocytes. Using this model, we demonstrate two important roles for the AIP protein in AHR biology. (i) The expression of AIP in hepatocytes is essential to maintain high levels of functional cytosolic AHR protein in the mammalian liver. (ii) Expression of the AIP protein is essential for dioxin-induced hepatotoxicity. Interestingly, classical AHR-driven genes show differential dependence on AIP expression. The Cyp1b1 and Ahrr genes require AIP expression for normal up-regulation by dioxin, whereas Cyp1a1 and Cyp1a2 do not. This differential dependence on AIP provides evidence that the mammalian genome contains more than one class of AHR-responsive genes and suggests that a search for AIP-dependent, AHR-responsive genes may guide us to the targets of the dioxin-induced hepatotoxicity.     

Common variants of xeroderma pigmentosum genes and prostate cancer risk

The genetic basis of prostate cancer (PC) is complex and appears to involve multiple susceptibility genes. A number of studies have evaluated a possible correlation between several NER gene polymorphisms and PC risk, but most of them evaluated only single SNPs among XP genes and the results remain inconsistent. Out of 94 SNPs located in seven XP genes (XPA–XPG) a total of 15 SNPs were assayed in 720 unselected patients with PC and compared to 1121 healthy adults. An increased risk of disease was associated with the XPD SNP, rs1799793 (Asp312Asn) AG genotype (OR = 2.60; p < 0.001) and with the AA genotype (OR = 531; p < 0.0001) compared to the control population. Haplotype analysis of XPD revealed one protective haplotype and four associated with an increased disease risk, which showed that the A allele (XPD rs1799793) appeared to drive the main effect on promoting prostate cancer risk. Polymorphism in XPD gene appears to be associated with the risk of prostate cancer.     

& 转录因子CBF在植物抗寒中的重要作用

低温能够诱导植物许多基因的表达,从而使植物具有抗寒性,这种现象称为冷驯化。对于植物冷驯化的分子机理,目前研究的最多的是CBF转录因子调控的信号转导途径,其作用途径可归纳为：CBF(C-repeat Binding Factor)转录因子→CRT/DRE(C-repeat /Dehydration Responsive Element)基序→COR基因表达→植物抗寒性增加。研究CBF转录因子在抗寒中的作用机制,能为提高植物的抗寒性,培育抗寒作物品种提供新方向。      

植物DREB转录因子的研究进展及应用

转录因子是一种DNA结合蛋白,通过与真核基因启动子区域中的顺式作用元件发生特异性相互作用来调控基因的转录。DREB(与干旱应答元件结合的)转录因子是一类新发现的植物特有的转录因子,能够特异地识别DRE(干旱应答元件)顺式作用元件并与之发生作用,从而激活植物体内一系列逆境应答基因的表达。本文综述了近几年在DREB转录因子的结构、功能、表达调控以及应用方面的研究进展。