Recently,some of the genetic mechanisms of heart specification have been elucidated in Drosophila .However,genes involved in early cardiogenesis of human remain to be identified.Since the pathways that regulate ear...Recently,some of the genetic mechanisms of heart specification have been elucidated in Drosophila .However,genes involved in early cardiogenesis of human remain to be identified.Since the pathways that regulate early cardiac fate determination are conserved between Drosophila and vertebrates,flies can be used as a model test system to explore the genetic basis of cardiogenesis in human.In this project,about 3000 reccieve lethal gene lines were produced by P or EMS mutagenesis.With staining of antibodies against heart precussor cells of Drosophila ,about 200 lines were observed to show heart phenotype.In pilot studies of their function with RNAi technique,the RNAi phenotypes of several genes tested were observed,which were very similar to that of their mutants,showing heart tube defects or no heart precursors formation.Taking advantage of the advanced genetic information available in the Drosophila and human systems,we have identified about 50 human transcripts homologous to the Drosophila heart related gene candidates.Northern blot analysis for some of the human candidates showed that several genes were expressed in both adult and early embryonic tissues,which may help in the evaluation of candidate genes for human cardiogenesis.Our further experiments with transgenic flies generated with wild type and mutant forms of these candidate genes to examine for defects in cardiogenesis or cardiac function are under way.The candidate genes producing cardiac specific defects suggestive of similarities to the heart disease syndromes can then be pursued further as likely disease gene candidates.Such an approach is likely to provide a dramatic reduction of possible candidate genes,or to screen and identify mutations that may generate the disease in human.展开更多
AIM: To evaluate the effect of Ocimum sanctum leaf extract on the dietary supplementation in the transgenic Drosophila model of Parkinson's disease. METHOD: The effect of Ocimum sanctum leaf extract was studied on...AIM: To evaluate the effect of Ocimum sanctum leaf extract on the dietary supplementation in the transgenic Drosophila model of Parkinson's disease. METHOD: The effect of Ocimum sanctum leaf extract was studied on the transgenic Drosophila model of flies expressing normal human alpha synuclein(h-αs) in the neurons. O. sanctum extract at final concentrations of 0.042 8 × 10-4, 0.87 × 10-4, and 1.85 × 10-4 g·mL-1 of diet were established and the flies were allowed to feed for 21 days. The climbing assay and lipid peroxidation were taken as parameters for the study. RESULTS: The supplementation of O. sanctum extract showed a dose-dependent significant delay in the loss of climbing ability and reduction in oxidative stress in the brain of PD model flies. CONCLUSION: The results of the present study showed that the O. sanctum extract is potent in reducing the PD symptoms in transgenic Drosophila model.展开更多
Cell competition is a struggle for existence between cells in heterogeneous tissues of multicellular organisms. Loser cells, which die during cell competition, are normally viable when grown only with other loser cell...Cell competition is a struggle for existence between cells in heterogeneous tissues of multicellular organisms. Loser cells, which die during cell competition, are normally viable when grown only with other loser cells, but when mixed with winner cells, they are at a growth disadvantage and undergo apoptosis. Intriguingly, several recent studies have revealed that cells bearing mutant tumor-suppressor genes, which show overgrowth and tumorigenesis in a homotypic situation, are frequently eliminated, through cell competition, from tissues in which they are surrounded by wild-type cells. Here, we focus on the regulation of cellular competitiveness and the mechanism of cell competition as inferred from two different categories of mutant cells： （1） slower-growing cells and （2） structurally defective cells. We also discuss the possible role of cell competition as an intrinsic homeostasis system through which normal cells sense and remove aberrant cells, such as precancerous cells, to maintain the integrity and normal development of tissues and organs.展开更多
文摘Recently,some of the genetic mechanisms of heart specification have been elucidated in Drosophila .However,genes involved in early cardiogenesis of human remain to be identified.Since the pathways that regulate early cardiac fate determination are conserved between Drosophila and vertebrates,flies can be used as a model test system to explore the genetic basis of cardiogenesis in human.In this project,about 3000 reccieve lethal gene lines were produced by P or EMS mutagenesis.With staining of antibodies against heart precussor cells of Drosophila ,about 200 lines were observed to show heart phenotype.In pilot studies of their function with RNAi technique,the RNAi phenotypes of several genes tested were observed,which were very similar to that of their mutants,showing heart tube defects or no heart precursors formation.Taking advantage of the advanced genetic information available in the Drosophila and human systems,we have identified about 50 human transcripts homologous to the Drosophila heart related gene candidates.Northern blot analysis for some of the human candidates showed that several genes were expressed in both adult and early embryonic tissues,which may help in the evaluation of candidate genes for human cardiogenesis.Our further experiments with transgenic flies generated with wild type and mutant forms of these candidate genes to examine for defects in cardiogenesis or cardiac function are under way.The candidate genes producing cardiac specific defects suggestive of similarities to the heart disease syndromes can then be pursued further as likely disease gene candidates.Such an approach is likely to provide a dramatic reduction of possible candidate genes,or to screen and identify mutations that may generate the disease in human.
文摘AIM: To evaluate the effect of Ocimum sanctum leaf extract on the dietary supplementation in the transgenic Drosophila model of Parkinson's disease. METHOD: The effect of Ocimum sanctum leaf extract was studied on the transgenic Drosophila model of flies expressing normal human alpha synuclein(h-αs) in the neurons. O. sanctum extract at final concentrations of 0.042 8 × 10-4, 0.87 × 10-4, and 1.85 × 10-4 g·mL-1 of diet were established and the flies were allowed to feed for 21 days. The climbing assay and lipid peroxidation were taken as parameters for the study. RESULTS: The supplementation of O. sanctum extract showed a dose-dependent significant delay in the loss of climbing ability and reduction in oxidative stress in the brain of PD model flies. CONCLUSION: The results of the present study showed that the O. sanctum extract is potent in reducing the PD symptoms in transgenic Drosophila model.
基金supported by National Science Foundation grant(IOS-1052333) and National Institutes of Health grant (R01GM072562) to W.-M.D.We thank Anne B.Thistle,John S.Poulton,Nicholas Leake,and Gengqiang Xie for critical reading and helpful input with the manuscript.
文摘Cell competition is a struggle for existence between cells in heterogeneous tissues of multicellular organisms. Loser cells, which die during cell competition, are normally viable when grown only with other loser cells, but when mixed with winner cells, they are at a growth disadvantage and undergo apoptosis. Intriguingly, several recent studies have revealed that cells bearing mutant tumor-suppressor genes, which show overgrowth and tumorigenesis in a homotypic situation, are frequently eliminated, through cell competition, from tissues in which they are surrounded by wild-type cells. Here, we focus on the regulation of cellular competitiveness and the mechanism of cell competition as inferred from two different categories of mutant cells： （1） slower-growing cells and （2） structurally defective cells. We also discuss the possible role of cell competition as an intrinsic homeostasis system through which normal cells sense and remove aberrant cells, such as precancerous cells, to maintain the integrity and normal development of tissues and organs.
