Pnas4 is a novel regulator for convergence and extension during vertebrate gastrulation

Recent studies show that human Pnas4 might be tumor associated, while its function remains unknown. Here, we investigate the developmental function of Pnas4 using zebrafish as a model system. Knocking down Pnas4 causes gastrulation defects with a shorter and broader axis, as well as a posteriorly mis-positioned prechordal plate, due to the defective convergence and extension movement. Conversely, over-expression of Pnas4 mRNA leads to an elongated body axis. We further demonstrate that Pnas4 is required cell-autonomously for dorsal convergence but not for anterior migration. In addition, genetic interaction assays indicate that Pnas4 might act in parallel with non-canonical Wnt signal in the regulation of cell movement. Our data suggest that Pnas4 is a key regulator of cell movement during gastrulation.     

利用基因诱捕技术进行小鼠基因剔除的初步研究

对利用基因诱捕技术进行小鼠基因剔除做了初步的探索,为进一步应用该技术进行小鼠基因功能研究奠定了基础.利用基因诱捕载体转染小鼠ES细胞,获得了36株neo基因单拷贝整合的诱捕ES细胞,其中14株细胞表达有活性的β半乳糖苷酶.将3株诱捕ES细胞分别经显微注射引入到受体囊胚中,再植入假孕母鼠的子宫中使其发育成小鼠.两株细胞得到了程度不同的嵌合体小鼠,其中一株诱捕ES细胞整合至生殖系.利用质粒拯救实验获得了诱捕载体整合位点附近的基因组序列,通过序列比对发现被诱捕的基因可能是一个新基因.X-gal染色结果显示,该基因的表达局限于小鼠腹部及肢芽的部位.     

糖尿病小型猪三磷酸腺苷结合盒转运体A1表达的变化

用贵州小香猪建立2型糖尿病动物模型,探讨糖尿病小型猪三磷酸腺苷结合盒转运体A1(ABCA1)表达的变化.采用高脂高蔗糖饲料喂养贵州小香猪,建立2型糖尿病动物模型.血浆总胆固醇、甘油三酯、高密度脂蛋白胆固醇和葡萄糖的浓度均用氧化酶法测定,血浆游离脂肪酸(FFA)用比色法测定, 采用逆转录-聚合酶链反应、蛋白质印迹和免疫组织化学分别检测ABCA1mRNA和蛋白质的表达.喂养6个月后,实验组与正常对照组比较,空腹血糖值明显升高;空腹胰岛素水平在头3个月轻度升高,在第6个月末其水平降低; 血清总胆固醇、甘油三酯和游离脂肪酸水平升高;肝组织、冠状动脉、肾组织ABCA1表达上调,同时观测到糖尿病小型猪肝组织LXRα表达上调.结果提示高脂高蔗糖饲料可引起小型猪脂质和糖代谢紊乱, 并导致肝组织、冠状动脉和肾组织ABCA1表达上调以及肝组织LXRα表达上调.     

VdNEP, an Elicitor from Verticillium dahliae, Induces Cotton Plant Wilting

Verticillium wilt is a vascular disease of cotton. The causal fungus, Verticillium dahliae, secretes elicitors in culture. We have generated ~1,000 5′-terminal expressed sequence tags (ESTs) from a cultured mycelium of V. dahliae. A number of ESTs were found to encode proteins harboring putative signal peptides for secretion, and their cDNAs were isolated. Heterologous expression led to the identification of a protein with elicitor activities. This protein, named V. dahliae necrosis- and ethylene-inducing protein (VdNEP), is composed of 233 amino acids and has high sequence identities with fungal necrosis- and ethylene-inducing proteins. Infiltration of the bacterially expressed His-VdNEP into Nicotiana benthamiana leaves resulted in necrotic lesion formation. In Arabidopsis thaliana, the fusion protein also triggered production of reactive oxygen species and induced the expression of PR genes. When added into suspension cultured cells of cotton (Gossypium arboreum), the fusion protein elicited the biosynthesis of gossypol and related sesquiterpene phytoalexins at low concentrations, and it induced cell death at higher concentrations. On cotton cotyledons and leaves, His-VdNEP induced dehydration and wilting, similar to symptoms caused by a crude preparation of V. dahliae elicitors. Northern blotting showed a low level of VdNEP expression in the mycelium during culture. These data suggest that VdNEP is a wilt-inducing factor and that it participates in cotton-V. dahliae interactions.     

华东天目山脉、黄山山脉、大别山脉竹类植物区系分析,兼论区系的起源与扩散

华东天目山脉、黄山山脉、大别山脉竹类植物较为丰富,分别有10属/75种(含种下等级)、8/49、7/30.通过对属、种的分布型分析,前二者竹类植物区系属于典型的华东区系,起源的时间不迟于早第三纪的始新世;而大别山脉虽仍属华东区系的范畴,因渗入了不少华中区系的成分,已具有某些经向过渡性特征,且起源的时间较晚.这3个山脉的竹类植物区系均具有显著的亚热带性质.天目山脉不仅是刚竹属Phyllostachys和短穗竹属Brachystachyum的分化变异中心,也极有可能就是它们的起源中心,但它们自此地起源后的散布方式有所不同,刚竹属在我国亚热带为四周放射状顺序渐进,扩散的范围颇广;短穗竹属存在东西南北4条散布路线,但向各方扩散的距离相差甚远.这些山脉与华东其他地区竹类植物区系联系密切,与华中竹类植物区系也有一定的联系,但与华南、西南等地竹类植物区系联系微弱.从地理位置和区系组成来看,黄山山脉的竹类植物区系来源于天目山脉,大别山脉的竹类植物区系又来源于黄山山脉,前者都是在后者扩展的基础上融合了其他区系的一些成分后发展而成,大别山脉又是北方秦岭以东广大丘陵平原地区竹类植物区系的发祥地.     

作物抗除草剂转基因研究进展

综述了抗除草剂基因研究的意义、研究机理及国内外研究现状,分析了各种转基因方法的优缺点,展望了除草剂抗性育种的发展方向。     

Modeling CADASIL vascular pathologies with patient-derived induced pluripotent stem cells

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy(CADASIL)is a rare hereditary cerebrovascular disease caused by a NOTCH3 mutation.However,the underlying cellular and molecular mechanisms remain unidentified.Here,we generated non-integrative induced pluripotent stem cells(iPSCs)from fibroblasts of a CADASIL patient harboring a heterozygous NOTCH3 mutation(c.3226C>T,p.R1076C).Vascular smooth muscle cells(VSMCs)differentiated from CADASIL-specific iPSCs showed gene expression changes associated with disease phenotypes,including activation of the NOTCH and NF-kB signaling pathway,cytoskeleton disorganization,and excessive cell proliferation.In comparison,these abnormalities were not observed in vascular endothelial cells(VECs)derived from the patients iPSCs.Importantly,the abnormal upregulation of NF-kB target genes in CADASIL VSMCs was diminished by a NOTCH pathway inhibitor,providing a potential therapeutic strategy for CADASIL.Overall,using this iPSCbased disease model,our study identified clues for studying the pathogenic mechanisms of CADASIL and developing treatment strategies for this disease.