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71.
A Positive GATA Element and a Negative Vitamin D Receptor-Like Element Control Atrial Chamber-Specific Expression of a Slow Myosin Heavy-Chain Gene during Cardiac Morphogenesis 总被引:1,自引:0,他引:1 下载免费PDF全文
Gang Feng Wang William Nikovits Jr. Mark Schleinitz Frank E. Stockdale 《Molecular and cellular biology》1998,18(10):6023-6034
We have used the slow myosin heavy chain (MyHC) 3 gene to study the molecular mechanisms that control atrial chamber-specific gene expression. Initially, slow MyHC 3 is uniformly expressed throughout the tubular heart of the quail embryo. As cardiac development proceeds, an anterior-posterior gradient of slow MyHC 3 expression develops, culminating in atrial chamber-restricted expression of this gene following chamberization. Two cis elements within the slow MyHC 3 gene promoter, a GATA-binding motif and a vitamin D receptor (VDR)-like binding motif, control chamber-specific expression. The GATA element of the slow MyHC 3 is sufficient for expression of a heterologous reporter gene in both atrial and ventricular cardiomyocytes, and expression of GATA-4, but not Nkx2-5 or myocyte enhancer factor 2C, activates reporter gene expression in fibroblasts. Equivalent levels of GATA-binding activity were found in extracts of atrial and ventricular cardiomyocytes from embryonic chamberized hearts. These observations suggest that GATA factors positively regulate slow MyHC 3 gene expression throughout the tubular heart and subsequently in the atria. In contrast, an inhibitory activity, operating through the VDR-like element, increased in ventricular cardiomyocytes during the transition of the heart from a tubular to a chambered structure. Overexpression of the VDR, acting via the VDR-like element, duplicates the inhibitory activity in ventricular but not in atrial cardiomyocytes. These data suggest that atrial chamber-specific expression of the slow MyHC 3 gene is achieved through the VDR-like inhibitory element in ventricular cardiomyocytes at the time distinct atrial and ventricular chambers form. 相似文献
72.
植物叶片功能性状能够响应环境条件的变化,反应了植物对环境的适应策略。当前,针对藤本植物叶片功能性状地理格局及其环境驱动力的研究较少。以国家重点保护植物永瓣藤(Monimopetalum chinense)为研究对象,对其分布区内11个种群的15个叶片功能性状进行测量,并结合气候、土壤因子来解释叶性状变异。比较叶片性状在局域和区域尺度上的种内变异程度,利用多元逐步回归分析环境因子对叶性状的影响。结果表明,在局域尺度上,永瓣藤叶功能性状变异系数介于3.0%-22.5%,其中,叶面积变异程度最大,叶片碳含量变异最小。永瓣藤叶片形状随纬度上升而变得宽且圆。叶片磷含量相对较低,永瓣藤的生长可能受到了磷限制。土壤与气候因子是叶片性状的重要驱动因素,解释了25%-97%的叶片性状变异。在温度和水分充足的情况下,永瓣藤叶片趋向于的慢速生长的保守策略。总体来说,永瓣藤叶片功能性状通过一定的种内变异和性状组合,并与气候、土壤因子相互作用,适应当前的环境条件。 相似文献
73.
C. Zhu J. Tong X. Yu W. Guo X. Wang H. Liu X. Feng Y. Sun L. Liu B. Fu 《Animal genetics》2014,45(5):699-708
Bighead carp (Aristichthys nobilis) is an important aquaculture fish worldwide. Genetic linkage maps for the species were previously reported, but map resolution remained to be improved. In this study, a second‐generation genetic linkage map was constructed for bighead carp through a pseudo‐testcross strategy using interspecific hybrids between bighead carp and silver carp. Of the 754 microsatellites genotyped in two interspecific mapping families (with 77 progenies for each family), 659 markers were assigned to 24 linkage groups, which were equal to the chromosome numbers of the haploid genome. The consensus map spanned 1917.3 cM covering 92.8% of the estimated bighead carp genome with an average marker interval of 2.9 cM. The length of linkage groups ranged from 52.2 to 133.5 cM with an average of 79.9 cM. The number of markers per linkage group varied from 11 to 55 with an average of 27.5 per linkage group. Normality tests on interval distances of the map showed a non‐normal marker distribution; however, significant correlation was found between the length of linkage group and the number of markers below the 0.01 significance level (two‐tailed). The length of the female map was 1.12 times that of the male map, and the average recombination ratio of female to male was 1.10:1. Visual inspection showed that distorted markers gathered in some linkage groups and in certain regions of the male and female maps. This well‐defined genetic linkage map will provide a basic framework for further genome mapping of quantitative traits, comparative mapping and marker‐assisted breeding in bighead carp. 相似文献
74.
Nina Bertaux-Skeirik Rui Feng Michael A. Schumacher Jing Li Maxime M. Mahe Amy C. Engevik Jose E. Javier Richard M. Peek Jr Karen Ottemann Veronique Orian-Rousseau Gregory P. Boivin Michael A. Helmrath Yana Zavros 《PLoS pathogens》2015,11(2)
The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific
constituent of Helicobacter pylori (H. pylori) that
augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell
signaling through the interaction with tyrosine kinase c-Met receptor, leading
cellular proliferation. Identified as a potential gastric stem cell marker,
cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but
whether it plays a functional role in H. pylori-induced epithelial
proliferation is unknown. We tested the hypothesis that CD44 plays a functional role
in H. pylori-induced epithelial cell proliferation. To assay changes
in gastric epithelial cell proliferation in relation to the direct interaction with
H. pylori, human- and mouse-derived gastric organoids were
infected with the G27 H. pylori strain or a mutant G27 strain
bearing cagA deletion (∆CagA::cat). Epithelial proliferation
was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by
immunoprecipitation followed by Western blot analysis for expression of CD44 and
CagA. H. pylori infection of both mouse- and human-derived gastric
organoids induced epithelial proliferation that correlated with c-Met
phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The
formation of this complex did not occur in organoids infected with
∆CagA::cat. Epithelial proliferation in response to
H. pylori infection was lost in infected organoids derived from
CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an
induction in proliferation when infected with H. pylorithat was not
seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the
well-established Mongolian gerbil model of gastric cancer, animals treated with CD44
peptide inhibitor Pep1, resulted in the inhibition of H.
pylori-induced proliferation and associated atrophic gastritis. The current
study reports a unique approach to study H. pylori interaction with
the human gastric epithelium. Here, we show that CD44 plays a functional role in
H. pylori-induced epithelial cell proliferation. 相似文献
75.
Do socioeconomic inequities in body mass index (BMI) widen across the adult lifecourse? BMI data for 29,104 male and 32,454 female person-years aged 15 years and older (21,403 persons in total) were extracted from the Household, Income and Labour Dynamics in Australia between 2006 and 2012. Multilevel linear regression was used to examine age and gender specific trajectories in BMI by quintiles of neighborhood socioeconomic circumstance. Models were adjusted for probable sources of confounding, including couple status, number of children resident, if somebody in the household had been pregnant in the last 12 months, the highest level of education achieved, the average household gross income, and the percentage of time in the last year spent unemployed. Approximately 9.6% of BMI variation was observed between neighborhoods. High neighborhood disadvantage was associated with 2.09 kg/m2 heavier BMI (95%CI 1.82, 2.36). At age 15-24y, socioeconomic inequity in BMI was already evident among men and women especially (22.6 kg/m2 among women in the most affluent areas compared with 25.4 kg/m2 among the most disadvantaged). Among women only, the socioeconomic gap widened from 2.8 kg/m2 at age 15-24y to 3.2 kg/m2 by age 35-44y. Geographical factors may contribute to more rapid weight gain among women living in disadvantaged neighborhoods. 相似文献
76.
77.
Ling Wang Yu Wang Yiguang Tian Jinling Shang Xiaoou Sun Hongzhuan Chen Hao Wang Wen Tan 《Bioorganic & medicinal chemistry》2017,25(1):360-371
A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC50 to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer’s disease (AD) treatment. 相似文献
78.
This study applies two variables in the measurement of company patent deployment strategies: patent family depth and earn plan ratio. Patent family depth represents the degree to which certain fields and markets are valued by the patent owner. Earn plan ratio defined as the ratio of the number of patent forward citations to patent family size. Earn plan ratio indicates the degree to which a patent family could be cited by later innovators and competitors. This study applies a logistic regression model in the analysis LED industry data. The results demonstrate that patent value has a positive relationship with the patent family depth, and earn plan ratio. 相似文献
79.
Abstract SV1 was observed to have obvious synergism and could delay housefly ( Musca domestica vicina ) resistance development to Dipterex. The penetration rates of Dipterex through housefly cuticle were determined in a susceptible and two resistant strains. The results indicated that the penetration in the resistant housefly strains was obviously slower than in the susceptible one. The penetrating rate of SV1 + Dipterex (in mixture) was higher than that of Dipterex. The penetration reduction in resistant houseflies may be an important factor in bringing forth resistance. The increase of the penetrating rate of Dipterex and the decrease of its metabolic rate are regarded as the important mechanisms of SV1 synergism to Dipterex. 相似文献
80.
四川雅安常见住区蝇类密度监测 总被引:2,自引:0,他引:2
根据全国常见住区蝇类密度监测课题组关于“全国常见住区蝇类密度监测实施计划”安排,雅安地区定力全国七个监测点之一,作者承担了这一任务。该项工作尚在继续进行中,现将1988年监测结果报道如下。 相似文献