Gastrointestinal stromal tumors(GISTs) are the most common soft tissue sarcoma of the gastrointestinal tract,resulting from an activating mutation of stem cell factor receptor(KIT),and an activating mutation of the ho...Gastrointestinal stromal tumors(GISTs) are the most common soft tissue sarcoma of the gastrointestinal tract,resulting from an activating mutation of stem cell factor receptor(KIT),and an activating mutation of the homologous platelet-derived growth factor receptor alpha(PDGFRA) kinase.Most GISTs(90%-95%) are KIT-positive.About 5% of GISTs are truly negative for KIT expression.GISTs have been documented to resistant conventional chemotherapeutics.Due to the KIT activation that occurs in the majority of the cases,KIT inhibition is the primary treatment approach in the adjuvant treatment of metastatic GISTs.Imatinib mesylate is an oral agent that is a selective protein tyrosine kinase inhibitor of the KIT protein tyrosine kinase,and it has demonstrated clinical benefit and objective tumor responses in most GIST patients in phase Ⅱ and Ⅲ trials.The presence and the type of KIT or PDGFRA mutation are predictive of response to imatinib therapy in patients with advanced and metastatic disease.Molecular analysis in phaseⅠ-Ⅱ trials revealed significant differences in objective response,progression-free survival,and overall survival between GISTs with different kinase mutations.The aim of this letter is to touch on the need for exon mutation analysis for adjuvant treatment with imatinib in GIST patients.展开更多
Aim: To specifically express the Asp567Gly human follicle-stimulating hormone receptor (FSHR) under the control of its promoter to evaluate the phenotypic consequences in the presence of normal pituitary function. Met...Aim: To specifically express the Asp567Gly human follicle-stimulating hormone receptor (FSHR) under the control of its promoter to evaluate the phenotypic consequences in the presence of normal pituitary function. Methods: We produced transgenic mice overexpressing the Asp567Gly human FSHR under the control of a 1.5kb 5' flanking region fragment of its promoter. Results: Mice were phenotypically normal and fertile. In males, mRNA could be detected in the testis and the brain, indicating that the 1.5kb promoter fragment drives expression not only in the gonads. The testis weight/body weight ratio and the testosterone levels in transgenic and non-transgenic litter mates were similar. By in situ hybridisation we found that the transgenic FSHR was highly expressed in Sertoli cells, spermatocytes and round spermatids. However, a radioligand receptor assay failed to show a significant difference in total FSHR binding sites in testis homogenates of transgenic and wild type animals, suggesting that the transgenic FSHR is probably not translated into functional receptor protein. Conclusion: A 1.5kb 5 '-region of the human FSHR drives mRNA expression of the transgene in the testis but leads to ectopic expression in germ cells and in the brain. No phenotypic consequences could be documented due to the lack of protein expression.展开更多
The K-Ras protein plays a key role in the signal transduction cascade. Certain mutations in K-Ras lead to a permanent “on” state which results in tumorigenesis due to failed interaction with the GTPase activating pr...The K-Ras protein plays a key role in the signal transduction cascade. Certain mutations in K-Ras lead to a permanent “on” state which results in tumorigenesis due to failed interaction with the GTPase activating protein (GAP). In this study, we examined the mutations E31N, D33N and D38N of K-Ras coupled and decoupled to wildtype GAP-334 and mutation K935N of GAP-334 coupled and decoupled to wildtype K-Ras, to illustrate the potential mechanism by which these mutants affect the interaction between the two proteins. We identify Tyr32 in the Ras Switch I region as a critical residue that acts as a gate to the GTP binding site and which needs to be “open” during Ras coupling with GAP to allow for insertion of GAP residue Arg789. This residue plays a vital role in stabilizing the transition state during GTP hydrolysis. The different mutations studied herein caused a reduced binding affinity, and the fluctuation of the Tyr32 side chain might hinder the insertion of Arg789. This may in turn be the cause of decreased GTP hydrolysis, and permanent “on” state of K-Ras, observed for these mutants.展开更多
We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the map...We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the mapbased cloning of the causal gene OsPELOTA（originally termed spl^（HM47））. We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1（eRF_1）, shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane.OsPELOTA is constitutively expressed in roots, leaves,sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.展开更多
Activated Phosphoinositide 3-kinase d syndrome(APDS)is a newly recognised primary immunodeficiency disease.It has currently been a hot topic of clinical research and new data are emerging regarding its pathogenesis,cl...Activated Phosphoinositide 3-kinase d syndrome(APDS)is a newly recognised primary immunodeficiency disease.It has currently been a hot topic of clinical research and new data are emerging regarding its pathogenesis,clinical manifestations and treatment.Patients with APDS syndrome have significant autoimmune manifestations and lymphoproliferation.It is important to differentiate APDS from the usual polygenic CVID in view of the availability of targeted therapy like mTOR inhibitors such as Rapamycin and selective PI3Kd inhibitors.We provide a comprehensive review on this interesting disorder focusing light on its etiology,genetic research and emerging therapy.展开更多
文摘Gastrointestinal stromal tumors(GISTs) are the most common soft tissue sarcoma of the gastrointestinal tract,resulting from an activating mutation of stem cell factor receptor(KIT),and an activating mutation of the homologous platelet-derived growth factor receptor alpha(PDGFRA) kinase.Most GISTs(90%-95%) are KIT-positive.About 5% of GISTs are truly negative for KIT expression.GISTs have been documented to resistant conventional chemotherapeutics.Due to the KIT activation that occurs in the majority of the cases,KIT inhibition is the primary treatment approach in the adjuvant treatment of metastatic GISTs.Imatinib mesylate is an oral agent that is a selective protein tyrosine kinase inhibitor of the KIT protein tyrosine kinase,and it has demonstrated clinical benefit and objective tumor responses in most GIST patients in phase Ⅱ and Ⅲ trials.The presence and the type of KIT or PDGFRA mutation are predictive of response to imatinib therapy in patients with advanced and metastatic disease.Molecular analysis in phaseⅠ-Ⅱ trials revealed significant differences in objective response,progression-free survival,and overall survival between GISTs with different kinase mutations.The aim of this letter is to touch on the need for exon mutation analysis for adjuvant treatment with imatinib in GIST patients.
文摘Aim: To specifically express the Asp567Gly human follicle-stimulating hormone receptor (FSHR) under the control of its promoter to evaluate the phenotypic consequences in the presence of normal pituitary function. Methods: We produced transgenic mice overexpressing the Asp567Gly human FSHR under the control of a 1.5kb 5' flanking region fragment of its promoter. Results: Mice were phenotypically normal and fertile. In males, mRNA could be detected in the testis and the brain, indicating that the 1.5kb promoter fragment drives expression not only in the gonads. The testis weight/body weight ratio and the testosterone levels in transgenic and non-transgenic litter mates were similar. By in situ hybridisation we found that the transgenic FSHR was highly expressed in Sertoli cells, spermatocytes and round spermatids. However, a radioligand receptor assay failed to show a significant difference in total FSHR binding sites in testis homogenates of transgenic and wild type animals, suggesting that the transgenic FSHR is probably not translated into functional receptor protein. Conclusion: A 1.5kb 5 '-region of the human FSHR drives mRNA expression of the transgene in the testis but leads to ectopic expression in germ cells and in the brain. No phenotypic consequences could be documented due to the lack of protein expression.
基金The Faculty of Science at the University of Gothenburg is gratefully acknowledged for financial support
文摘The K-Ras protein plays a key role in the signal transduction cascade. Certain mutations in K-Ras lead to a permanent “on” state which results in tumorigenesis due to failed interaction with the GTPase activating protein (GAP). In this study, we examined the mutations E31N, D33N and D38N of K-Ras coupled and decoupled to wildtype GAP-334 and mutation K935N of GAP-334 coupled and decoupled to wildtype K-Ras, to illustrate the potential mechanism by which these mutants affect the interaction between the two proteins. We identify Tyr32 in the Ras Switch I region as a critical residue that acts as a gate to the GTP binding site and which needs to be “open” during Ras coupling with GAP to allow for insertion of GAP residue Arg789. This residue plays a vital role in stabilizing the transition state during GTP hydrolysis. The different mutations studied herein caused a reduced binding affinity, and the fluctuation of the Tyr32 side chain might hinder the insertion of Arg789. This may in turn be the cause of decreased GTP hydrolysis, and permanent “on” state of K-Ras, observed for these mutants.
基金supported by the National Natural Science Foundation of China (31471572)the Ministry of Science and Technology of China (2016YFD0101104)
文摘We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the mapbased cloning of the causal gene OsPELOTA（originally termed spl^（HM47））. We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1（eRF_1）, shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane.OsPELOTA is constitutively expressed in roots, leaves,sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.
文摘Activated Phosphoinositide 3-kinase d syndrome(APDS)is a newly recognised primary immunodeficiency disease.It has currently been a hot topic of clinical research and new data are emerging regarding its pathogenesis,clinical manifestations and treatment.Patients with APDS syndrome have significant autoimmune manifestations and lymphoproliferation.It is important to differentiate APDS from the usual polygenic CVID in view of the availability of targeted therapy like mTOR inhibitors such as Rapamycin and selective PI3Kd inhibitors.We provide a comprehensive review on this interesting disorder focusing light on its etiology,genetic research and emerging therapy.
