猪骨骼肌MyHC-Ⅱb基因上调表达的分子机制

哺乳动物骨骼肌由各种不同类型的肌纤维镶嵌而成,不同类型肌球蛋白重链的表达是造成不同类型肌纤维的主要原因.目前已知的肌球蛋白重链家族包含8种亚型,其中长白猪骨骼肌My HC-Ⅱb的表达量显著高于中国地方猪,然而造成这种差异的分子机制未见报道.本研究用荧光定量PCR证明了长白猪背最长肌中My HC-Ⅱb m RNA的表达量显著高于莱芜猪(P=0.013).删除实验结果表明,从转录起始位点上游-1024 bp删除到-187 bp之后,My HC-Ⅱb表达量显著下降,分析发现,在这段启动子区域内存在3个E-box序列;分别突变这3个E-box序列后,My HC-Ⅱb启动子驱动的荧光素酶活性显著下降(P=0.036).另外,在My HC-Ⅱb上游启动子区?1398 bp处发现一个GT的突变,所检测的64头莱芜猪在该位点全部为GG型,65头长白猪中13头为GG型,16头为TT型,36头为GT型.在C2C12细胞系中的转染实验结果显示,G突变为T之后有增加My HC-Ⅱb表达的趋势.Western blot的结果表明,转录因子Myo D在两猪种间表达差异不显著(P=0.136),而Myf-5在长白猪中的表达量极显著高于其在莱芜猪中的表达量(P=0.0036).这些数据表明,Myf-5是造成猪My HC-Ⅱb基因m RNA上调表达的重要因素之一.     

洞庭湖流域麋鹿等哺乳动物濒危灭绝原因的分析及其对麋鹿重引入的启示

洞庭湖流域曾有亚洲象(Elephasmaximus)、犀(Rhinocerossp.)、麋鹿(Elaphurusdavidianus)、川金丝猴(Rhinopithecusroxellana)、长臂猿(Hylobatessp.)、大熊猫(Ailuropodamelanoleuca)、梅花鹿(Cervusnippon)、棕熊(Ursusarctos)等哺乳动物分布,但受古气候、古地理以及人类活动的影响,这些哺乳动物已在洞庭湖流域灭绝。这些哺乳动物的濒危和灭绝既受自然环境变化和灾变的影响,也与物种本身生物学特性和人类活动有关,尤其与人类捕杀和生境丧失有关。据古籍记载分析:在洞庭湖流域,亚洲象和犀于北宋末期灭绝或已南迁,而野生麋鹿、大熊猫、川金丝猴、长臂猿、梅花鹿和棕熊等于19世纪末灭绝。根据我们对30个自然保护区或森林公园野生动物资源实地调查的结果,在洞庭湖流域已记录到21种国家重点保护哺乳动物,其中有5、6、10种哺乳动物分别处于“极危”、“濒危”、“易危”等级,这表明物种濒危的过程仍在继续。导致这些现生哺乳动物濒危的主要原因是生境丧失、人类猎捕、环境污染等,而人类活动干扰对现生濒危物种存活的影响越来越大。洞庭湖流域重引入麋鹿需采取人类协助生存策略:提供足够的且受洪水影响小的适宜生境、保证稳定的奠基者种群数量、减少人为干扰、调控种群密度、实施社区共管和生计替代项目、加强疾病防治、完善保护措施、加大保护基金投入、加强生境监测和湿地恢复等。     

Neural progenitor cells from human induced pluripotent stem cells generated less autogenous immune response

The breakthrough development of induced pluripotent stem cells(iPSCs)raises the prospect of patient-specific treatment for many diseases through the replacement of affected cells.However,whether iPSC-derived functional cell lineages generate a deleterious immune response upon auto-transplantation remains unclear.In this study,we differentiated five human iPSC lines from skin fibroblasts and urine cells into neural progenitor cells(NPCs)and analyzed their immunogenicity.Through co-culture with autogenous peripheral blood mononuclear cells(PBMCs),we showed that both somatic cells and iPSC-derived NPCs do not stimulate significant autogenous PBMC proliferation.However,a significant immune reaction was detected when these cells were co-cultured with allogenous PBMCs.Furthermore,no significant expression of perforin or granzyme B was detected following stimulation of autogenous immune effector cells(CD3+CD8 T cells,CD3+CD8+T cells or CD3 CD56+NK cells)by NPCs in both PBMC and T cell co-culture systems.These results suggest that human iPSC-derived NPCs may not initiate an immune response in autogenous transplants,and thus set a base for further preclinical evaluation of human iPSCs.     

Bidirectional effect of Wnt signaling antagonist DKK1 on the modulation of anthrax toxin uptake

LRP6,a co-receptor for the morphogen Wnt,aids endocytosis of anthrax complexes.Here we report that Dickkopf1(DKK1)protein,a secreted LRP6 ligand and antagonist,is also a modulator of anthrax toxin sensitivity.shRNA-mediated gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of cells to PA-dependent hybrid toxins.However,unlike the solely inhibitory effect on Wnt signaling,the effects of DKK1 overexpression on anthrax toxicity were bidirectional,depending on its endogenous expression and cell context.Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates internalization of anthrax toxins and their receptors,an event mediated by DKK1-LRP6-Kremen2 complex.Monoclonal antibodies against DKK1 provided dose-dependent protection to macrophages from killing by anthrax lethal toxin(LT).Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in promoting PA-mediated toxin internalization provides a paradigm for bacterial exploitation of mechanisms that host cells use to internalize signaling proteins.     

斑马鱼母源因子在胚胎发育中的作用

动物受精时,精子主要是将雄原核释放到卵子中,形成的合子中雌、雄原核融合为合子核,但受精卵基因组在前几次有丝分裂过程中不转录,合理的逻辑性推测是其早期发育完全依赖于卵质中储存的RNA和蛋白质,即母源因子.上世纪80年代对无脊椎动物的正向遗传研究发现,母源因子在卵子和胚胎极性的决定、早期胚胎的图式形成等方面发挥了决定性作用.过去10多年来,通过对斑马鱼和小鼠突变体的研究,也证明母源因子在脊椎动物胚胎早期发育中起着重要作用.本文主要综述斑马鱼母源因子在卵母细胞的极性、卵子的激活、早期细胞分裂、母源mRNA的清除、合子基因转录激活以及胚层的形成和分化、体轴的建立等方面的作用,相关知识对于研究人类生育障碍和先天性疾病的发生机制和诊治有借鉴意义.     

A quantification model for apoptosis in mouse embryos in the early stage of fetation

Apoptosis is the most important inducement and modulator for embryos in the early stage of fetation, i.e. after the 8-cell stage, mostly the morula and blastula stage, to proceed to the stage of nonlinear development. Using a two-photon laser scanning microscopy (TPLSM) system, we obtained 3-dimensional (3D) fluorescent images of preimplantation mouse embryos. A model for quantification was established. The statistical results for the spatial location of apoptosis bodies in embryos was obtained following image processing, as well as investigation of the kinetics of apoptosis. It was found that most (70%) apoptosis occurred in the trophectoderm, and the departure between the centroid and geometric center of embryos had a step transition when embryos developed into the 32-cell stage, which was consistent with the theoretical prediction that the blastocele would induce a symmetry break of the distribution of cells in embryos.     

Reference Gene Selection for Real-Time Quantitative PCR Analysis of the Mouse Uterus in the Peri-Implantation Period

The study of uterine gene expression patterns is valuable for understanding the biological and molecular mechanisms that occur during embryo implantation. Real-time quantitative RT-PCR (qRT-PCR) is an extremely sensitive technique that allows for the precise quantification of mRNA abundance; however, selecting stable reference genes suitable for the normalization of qRT-PCR data is required to avoid the misinterpretation of experimental results and erroneous analyses. This study employs several mouse models, including an early pregnancy, a pseudopregnancy, a delayed implantation and activation, an artificial decidualization and a hormonal treatment model; ten candidate reference genes (PPIA, RPLP0, HPRT1, GAPDH, ACTB, TBP, B2M, 18S, UBC and TUBA) that are found in uterine tissues were assessed for their suitability as internal controls for relative qRT-PCR quantification. GeNorm^PLUS, NormFinder, and BestKeeper were used to evaluate these candidate reference genes, and all of these methods identified RPLP0 and GAPDH as the most stable candidates and B2M and 18S as the least stable candidates. However, when the different models were analyzed separately, the reference genes exhibited some variation in their expression levels.     

GRP78 expression and regulation in the mouse uterus during embryo implantation

The aim of this study was to investigate the spatiotemporal expression and regulation of GRP78 in the mouse uterus during the peri-implantation period. The GRP78 protein was mainly detected in the luminal and glandular epithelia on days 1–4 of pregnancy. On day 5 of pregnancy, the GRP78 protein was more highly observed around the implanted embryo at the implantation site. There was no detectable GRP78 protein signal on day 5 of pseudopregnancy. GRP78 mRNA and protein levels gradually increased on days 6–8 of pregnancy, and the expression pattern was also expanded, coinciding with the development of decidua. Similarly, GRP78 expression was also strongly expressed in decidualised cells following artificial decidualisation. Compared with the results obtained with the delayed uterus, a high level of GRP78 expression was detected in the implantation-activated uterus. In the uteri of ovariectomised mice, GRP78 expression increased and reached its highest level after injection of oestrogen, and progesterone seemed to have an antagonistic effect on oestrogen up-regulation of GRP78 expression. Our data indicate that GRP78 might play an important role during the process of mouse embryo implantation, and GRP78 expression was mainly regulated by active blastocysts and maternal oestrogen.     

Genetic diversity analysis of crucian carp (Carassius auratus) based on cyt b and D-loop-containing region around Hongze Lake

Environmental Biology of Fishes - Crucian carp (Carassius auratus) is an important freshwater aquaculture species in China. The study of the genetic diversity of native crucian carp will provide...