154 research outputs found

    French Protestant Families in Canadian Trade 1740-1760

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    Development of an SDG interlinkages analysis model at the river basin scale: a case study in the Luanhe River Basin, China

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    While the Sustainable Development Goals (SDG) are broadly framed with 17 goals, the goals and their targets inherently connect with each other forming a complex system. Actions supporting one goal may influence progress in other goals, either positively (synergies) or negatively (trade-offs). Effective managing the synergies and trade-offs is a prerequisite for ensuring policy coherence. This is particular relevant at the river basin scale where the implementation of national policies may generate inequalities at the sub-basin levels, such as the upstream and the downstream. In the existing literature, there is still a lack of methodologies to assess the SDG interlinkages and their differences at the subnational levels. This paper presents a methodology on the development of an SDG interlinkages analysis model at the basin scale and its application to a case study in China’s Luanhe River Basin (LRB). Seven broad areas, namely land use and land cover change, climate change, ecosystem services, flood risks, water sector, urbanisation, and energy, were set as the scope of study. Through a systematic review, key elements of the SDG interlinkages system were identified and their interactions were mapped. The resulting generic SDG interlinkages model were validated with expert survey and stakeholders’ consultation and tailored to the LRB. Quantification of the SDG interlinkages was conducted for 27 counties in the LRB and demonstrated by the results of 3 selected counties located in the upstream, midstream and downstream areas, respectively. The methodology and its applications can be used to support integrated water resource management in river basins

    The combined immunodetection of AP-2Ξ± and YY1 transcription factors is associated with ERBB2 gene overexpression in primary breast tumors

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    INTRODUCTION: Overexpression of the ERBB2 oncogene is observed in about 20% of human breast tumors and is the consequence of increased transcription rates frequently associated with gene amplification. Several studies have shown a link between activator protein 2 (AP-2) transcription factors and ERBB2 gene expression in breast cancer cell lines. Moreover, the Yin Yang 1 (YY1) transcription factor has been shown to stimulate AP-2 transcriptional activity on the ERBB2 promoter in vitro. In this report, we examined the relationships between ERBB2, AP-2alpha, and YY1 both in breast cancer tissue specimens and in a mammary cancer cell line. METHODS: ERBB2, AP-2alpha, and YY1 protein levels were analyzed by immunohistochemistry in a panel of 55 primary breast tumors. ERBB2 gene amplification status was determined by fluorescent in situ hybridization. Correlations were evaluated by a chi2 test at a p value of less than 0.05. The functional role of AP-2alpha and YY1 on ERBB2 gene expression was analyzed by small interfering RNA (siRNA) transfection in the BT-474 mammary cancer cell line followed by real-time reverse transcription-polymerase chain reaction and Western blotting. RESULTS: We observed a statistically significant correlation between ERBB2 and AP-2alpha levels in the tumors (p < 0.01). Moreover, associations were found between ERBB2 protein level and the combined high expression of AP-2alpha and YY1 (p < 0.02) as well as between the expression of AP-2alpha and YY1 (p < 0.001). Furthermore, the levels of both AP-2alpha and YY1 proteins were inversely correlated to ERBB2 gene amplification status in the tumors (p < 0.01). Transfection of siRNAs targeting AP-2alpha and AP-2gamma mRNAs in the BT-474 breast cancer cell line repressed the expression of the endogenous ERBB2 gene at both the mRNA and protein levels. Moreover, the additional transfection of an siRNA directed against the YY1 transcript further reduced the ERBB2 protein level, suggesting that AP-2 and YY1 transcription factors cooperate to stimulate the transcription of the ERBB2 gene. CONCLUSION: This study highlights the role of both AP-2alpha and YY1 transcription factors in ERBB2 oncogene overexpression in breast tumors. Our results also suggest that high ERBB2 expression may result either from gene amplification or from increased transcription factor levels

    Identification of target genes of transcription factor activator protein 2 gamma in breast cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Activator protein 2 gamma (AP-2Ξ³) is a member of the transcription factor activator protein-2 (AP-2) family, which is developmentally regulated and plays a role in human neoplasia. AP-2Ξ³ has been found to be overexpressed in most breast cancers, and have a dual role to inhibit tumor initiation and promote tumor progression afterwards during mammary tumorigensis.</p> <p>Methods</p> <p>To identify the gene targets that mediate its effects, we performed chromatin immunoprecipitation (ChIP) to isolate AP-2Ξ³ binding sites on genomic DNA from human breast cancer cell line MDA-MB-453.</p> <p>Results</p> <p>20 novel DNA fragments proximal to potential AP-2Ξ³ targets were obtained. They are categorized into functional groups of carcinogenesis, metabolism and others. A combination of sequence analysis, reporter gene assays, quantitative real-time PCR, electrophoretic gel mobility shift assays and immunoblot analysis further confirmed the four AP-2Ξ³ target genes in carcinogenesis group: ErbB2, CDH2, HPSE and IGSF11. Our results were consistent with the previous reports that ErbB2 was the target gene of AP-2Ξ³. Decreased expression and overexpression of AP-2Ξ³ in human breast cancer cells significantly altered the expression of these four genes, indicating that AP-2Ξ³ directly regulates them.</p> <p>Conclusion</p> <p>This suggested that AP-2Ξ³ can coordinate the expression of a network of genes, involving in carcinogenesis, especially in breast cancer. They could serve as therapeutic targets against breast cancers in the future.</p

    Different mechanisms are implicated in ERBB2 gene overexpression in breast and in other cancers

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    The ERBB2 gene is overexpressed in 30% of breast cancers and this has been correlated with poor prognosis. ERBB2 is upregulated in other cancers such as prostate, pancreas, colon and ovary. In breast cancer cells, the mechanisms leading to ERBB2 gene overexpression are increased transcription and gene amplification. In these cancers, AP-2 transcription factors are involved in ERBB2 overexpression, and AP-2 levels are correlated with p185(c-erbB-2) levels. In this work, we wanted to know if the same molecular mechanisms are responsible for the ERBB2 upregulation in non-breast cancers. We compared ERBB2 gene copy number, p185(c-erbB-2) and mRNA levels with AP-2 levels in several ovary, prostate, colon and pancreas cancer cells. A moderate expression of erbB-2 mRNA and protein were observed in some cells without gene amplification. In contrast to breast cancer cells, AP-2 factors were absent or low in some non-breast cells which did express ERBB2. It is thus likely that AP-2 is not a major player in the increased levels of erbB-2 transcripts in non-breast cancer cells. The transcriptional activity of the ERBB2 promoter in colon and ovary cancer cells was estimated using reporter vectors. The results showed that the promoter regions involved in ERBB2 gene overexpression in breast cancer cells are different from those that lead to the gene upregulation in colon and ovary cancers. In conclusion, our results indicate that different transcriptional and post-transcriptional mechanisms are responsible for the increased levels of erbB-2 transcript and protein in breast and non-breast cancer cells

    Structural and Functional Evaluation of C. elegans Filamins FLN-1 and FLN-2

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    Filamins are long, flexible, multi-domain proteins composed of an N-terminal actin-binding domain (ABD) followed by multiple immunoglobulin-like repeats (IgFLN). They function to organize and maintain the actin cytoskeleton, to provide scaffolds for signaling components, and to act as mechanical force sensors. In this study, we used transcript sequencing and homology modeling to characterize the gene and protein structures of the C. elegans filamin orthologs fln-1 and fln-2. Our results reveal that C. elegans FLN-1 is well conserved at the sequence level to vertebrate filamins, particularly in the ABD and several key IgFLN repeats. Both FLN-1 and the more divergent FLN-2 colocalize with actin in vivo. FLN-2 is poorly conserved, with at least 23 IgFLN repeats interrupted by large regions that appear to be nematode-specific. Our results indicate that many of the key features of vertebrate filamins are preserved in C. elegans FLN-1 and FLN-2, and suggest the nematode may be a very useful model system for further study of filamin function

    Aurora-A Interacts with AP-2Ξ± and Down Regulates Its Transcription Activity

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    Aurora-A is a serine/threonine protein kinase and plays an important role in the control of mitotic progression. Dysregulated expression of Aurora-A impairs centrosome separation and maturation, which lead to disrupted cell cycle progression and tumorigenesis. However, the molecular mechanism by which Aurora-A causes cell malignant transformation remains to be further defined. In this report, using transcription factors array and mRNA expression profiling array, we found that overexpression of Aurora-A suppressed transcription activity of AP-2Ξ±, a tumor suppressor that is often downregulated in variety of tumors, and inhibited expression of AP-2Ξ±-regulated downstream genes. These array-based observations were further confirmed by microwell colorimetric TF assay and luciferase reporter assay. Downregulated transcription activity of AP-2Ξ± by Aurora-A was found to be associated with reduced AP-2Ξ± protein stability, which appeared to be mediated by Aurora-A enhanced ubiquitin-dependent proteasomal degradation of AP-2Ξ± protein. Interestingly, Aurora-A-mediated AP-2Ξ± degradation was likely dependent Aurora-A kinase activity since inhibition of Aurora-A kinase activity was able to rescue Aurora-A-induced degradation of AP-2Ξ±. Moreover, we defined a physical interaction between Aurora-A and AP-2Ξ±, and such interaction might bridge the suppressive effect of Aurora-A on AP-2Ξ± protein stability. These findings provide new insights into molecular mechanism by which Aurora-A acts as an oncogenic molecule in tumor occurrence and malignant development

    A Novel Sperm-Delivered Toxin Causes Late-Stage Embryo Lethality and Transmission Ratio Distortion in C. elegans

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    The evolutionary fate of an allele ordinarily depends on its contribution to host fitness. Occasionally, however, genetic elements arise that are able to gain a transmission advantage while simultaneously imposing a fitness cost on their hosts. We previously discovered one such element in C. elegans that gains a transmission advantage through a combination of paternal-effect killing and zygotic self-rescue. Here we demonstrate that this element is composed of a sperm-delivered toxin, peel-1, and an embryo-expressed antidote, zeel-1. peel-1 and zeel-1 are located adjacent to one another in the genome and co-occur in an insertion/deletion polymorphism. peel-1 encodes a novel four-pass transmembrane protein that is expressed in sperm and delivered to the embryo via specialized, sperm-specific vesicles. In the absence of zeel-1, sperm-delivered PEEL-1 causes lethal defects in muscle and epidermal tissue at the 2-fold stage of embryogenesis. zeel-1 is expressed transiently in the embryo and encodes a novel six-pass transmembrane domain fused to a domain with sequence similarity to zyg-11, a substrate-recognition subunit of an E3 ubiquitin ligase. zeel-1 appears to have arisen recently, during an expansion of the zyg-11 family, and the transmembrane domain of zeel-1 is required and partially sufficient for antidote activity. Although PEEL-1 and ZEEL-1 normally function in embryos, these proteins can act at other stages as well. When expressed ectopically in adults, PEEL-1 kills a variety of cell types, and ectopic expression of ZEEL-1 rescues these effects. Our results demonstrate that the tight physical linkage between two novel transmembrane proteins has facilitated their co-evolution into an element capable of promoting its own transmission to the detriment of organisms carrying it
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