Recent studies have revealed that osthole,an active constituent isolated from the fruit of Cnidium monnieri（L.） Cusson,a traditional Chinese medicine,possesses anticancer activity.However,its effect on breast cancer...Recent studies have revealed that osthole,an active constituent isolated from the fruit of Cnidium monnieri（L.） Cusson,a traditional Chinese medicine,possesses anticancer activity.However,its effect on breast cancer cells so far has not been elucidated clearly.In the present study,we evaluated the effects of osthole on the proliferation,cell cycle and apoptosis of human breast cancer cells MDA-MB 435.We demonstrated that osthole is effective in inhibiting the proliferation of MDA-MB 435 cells,The mitochondrion-mediated apoptotic pathway was involved in apoptosis induced by osthole,as indicated by activation of caspase-9 and caspase-3 followed by PARP degradation.The mechanism underlying its effect on the induction of G1 phase arrest was due to the up-regulation of p53 and p21 and down-regulation of Cdk2 and cyclin D1 expression.Were observed taken together,these findings suggest that the anticancer efficacy of osthole is mediated via induction of cell cycle arrest and apoptosis in human breast cancer cells and osthole may be a potential chemotherapeutic agent against human breast cancer.展开更多
The development of the Wolffian/epididymal duct is crucial for proper function and, therefore, male fertility. The development of the epididymis is complex; the initial stages form as a transient embryonic kidney; the...The development of the Wolffian/epididymal duct is crucial for proper function and, therefore, male fertility. The development of the epididymis is complex; the initial stages form as a transient embryonic kidney; then the mesonephros is formed, which in turn undergoes extensive morphogenesis under the influence of androgens and growth factors. Thus, understanding of its full development requires a wide and multidisciplinary view. This review focuses on mouse models that display abnormalities of the Wolffian duct and mesonephric development, the importance of these mouse models toward understanding male reproductive tract development, and how these models contribute to our understanding of clinical abnormalities in humans such as congenital anomalies of the kidney and urinary tract （CAKUT）.展开更多
Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matc...Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matched paraneoplastic normal tissues, and to explore the intrinsic mechanism of OSCC development and progres- sion. We obtained the differentially expressed mRNA expression profiles in 10 pairs of fresh-frozen OSCC tissue specimens and matched paraneoplastic normal tissue specimens by high-throughput RNA sequencing. By using Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses, the functional significance of the differentially expressed genes were analyzed. We identified 1,120 sig- nificantly up-regulated mRNAs and 178 significantly down-regulated mRNAs in OSCC, compared to normal tissue. The differentially expressed mRNAs were involved in 20 biological processes and 68 signal pathways. Compared to adjacent normal tissue, the expression of MAGEAll was up-regulated; TCHH was down-regulated. These find- ings were verified by real-time PCR. These differentially expressed mRNAs may function as oncogenes or tumor suppressors in the development and progression of OSCC. This study provides novel insights into OSCC. However, further work is needed to determine if these differentially expressed mRNAs have potential roles as diagnostic bio- markers and candidate therapeutic targets for OSCC.展开更多
Medulloblastoma is the most common malignant pediatric brain tumor. Some are thought to originate from cerebellar granule neuron progenitors （CGNPs） that fail to undergo normal cell cycle exit and differentiation. T...Medulloblastoma is the most common malignant pediatric brain tumor. Some are thought to originate from cerebellar granule neuron progenitors （CGNPs） that fail to undergo normal cell cycle exit and differentiation. The contribution of microRNAs to the initiation and progression of medulloblastoma remains poorly understood. Increased expression of the miR-183-96-182 cluster of microRNAs has been noted in several aggressive sub- groups. We identified that expression of miR-183-96-182 was higher in medulloblastomas with Pten gene loss in the background of the activated sonic hedgehog （Shh） signaling pathway. Ectopic miR-183-96-182 expression in CGNPs synergized with exogenous Shh to increase proliferation and its role depended on hedgehog signaling ac- tivation. Our findings suggest a new microRNA cluster, the miR-183-96-182, functionally collaborates with the Shh signaling pathway in the development of medulloblastomas in mice.展开更多
The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin ...The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin （MTx）, a Ca2＋-mobilizing agent, has been shown to be a potent inducer of the mouse sperm AR, with a pharmacology similar to that of the zona pellucida （ZP）, possibly suggesting a common pathway for both inducers. Using recombinant human ZP3 （rhZP3）, mouse ZP and two MTx channel blockers （U73122 and U73343）, we investigated and compared the MTx- and ZP-induced ARs in human and mouse spermatozoa. Herein, we report that MTx induced AR and elevated intracellular Ca2＋ （[Ca2＋]~） in human spermatozoa, both of which were blocked by U73122 and U73343. These two compounds also inhibited the MTx-induced AR in mouse spermatozoa. In disagreement with our previous proposal, the AR triggered by rhZP3 or mouse ZP was not blocked by U73343, indicating that in human and mouse spermatozoa, the AR induction by the physiological ligands or by MTx occurred through distinct pathways. U73122, but not U73343 （inactive analogue）, can block phospholipase C （PLC）. Another PLC inhibitor, edelfosine, also blocked the rhZP3- and ZP-induced ARs. These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR. Notably, edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human, suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.展开更多
Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key do...Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.展开更多
Apoptosis plays an important role in the pathogenesis of viral infections.In this study,we investigated the cell death processes during productive HHV-6A infection and the underlying mechanisms.Annexin V-PI staining a...Apoptosis plays an important role in the pathogenesis of viral infections.In this study,we investigated the cell death processes during productive HHV-6A infection and the underlying mechanisms.Annexin V-PI staining and electron microscopy indicated that HHV-6A is a strong inducer of apoptosis.HHV-6A infection decreased mitochondrial transmembrane potential and led to morphological changes of mitochondria.The cell death was associated with activation of caspase-3 and cleavage of DNA repair enzyme poly （ADP-ribose） polymerase,which is known to be an important substrate for activated caspase-3.Caspase-9 was activated significantly in HHV-6A-infected cells,whereas caspase-8 was not activated obviously.Moreover,HHV-6A infection upregulated Bax and downregulated Bcl-2.This is the first demonstration of mitochondrion-mediated,caspase-dependent apoptosis in HHV-6A-infected cells.展开更多
Constitutive hedgehog （Hh） signaling is associated with the genesis of medulloblastomas （MB）. The objective of this study is to identify special microRNAs （miRNAs） regulated by the Hh pathway, and to clarify the...Constitutive hedgehog （Hh） signaling is associated with the genesis of medulloblastomas （MB）. The objective of this study is to identify special microRNAs （miRNAs） regulated by the Hh pathway, and to clarify the role of miRNAs during the genesis of MB induced by sustained Hh activation. In the primary screening, we used stemloop RT-PCR to test the expression of 90 different miRNAs in the wildtype （WT） and Ptc-/- MEF cell lines. In the secondary screening, the miRNAs screened from the first screening were validated in the Sufu-/- MEF cell lines. We then verified the expression of miRNAs both in the normal cerebellar tissues and the MB induced by activated Hh pathway, and examined the expression of the other 21 miRNA members of the miR-154 cluster in the MB and normal cerebellum. In the first screening, 13 miRNAs showed significant differential expression in WT and Ptc-/- MEF cell lines, while 10 of them had significant difference in the Sufu-/- MEF cell line. Compared to the normal mouse cerebellum, only 2 miRNAs in 15 miRNAs were differentially expressed between the MB and normal cerebellar tissues. Among 21 members of the miR-154 cluster, 6 miRNAs were downregulated in the MB. Our study demonstrated that miR-154 may be regulated by the Hh pathway, and the activation of the Hh pathway led to the downregulation of the miR-154 cluster, resulting in the genesis of MB.展开更多
Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gen...Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gene discs large （dig） encodes a septate junction protein functioning during epithelial polarization, asymmetric neuroblast division, and formation of neuromuscular junctions. Here, we report the role of dig in testis development and its critical function in somatic cyst cells （SCCs）. In these cells dig is primarily required for their survival and expansion, and contributes to spermatocyte cyst differentiation. Cell death primarily occurred in SCCs at the end of spermatogonial amplification at a time when Dig becomes restricted in wild-type （wt） testes to the distal somatic cells capping the growing spermatocyte cysts. RNAi depletion of dig transcripts in early SCCs fully prevented testis development, whereas depletion in late SCCs resulted in a breakdown of spermatocyte cyst structure and germ cell individualization. Specific dig expression in SCCs resulted in developmental rescue of dig mutant testes, whereas its expression in germ cells exerted no such effect, dig overexpression in wt testes led to spermatocyte cyst expansion at the expense of spermatogonial cysts. Our data demonstrate that dig is essentially required in SCCs for their survival, expansion, and differentiation, and for the encapsulation of the germline cells.展开更多
In a 1989 Hollywood hit“Sex,Lies,and Videotapes”,director Steven Soderbergh told a story of an incestuous affair between a hot-shot lawyer and the sister of his married wife.An over-stayed visit by a drifter whose u...In a 1989 Hollywood hit“Sex,Lies,and Videotapes”,director Steven Soderbergh told a story of an incestuous affair between a hot-shot lawyer and the sister of his married wife.An over-stayed visit by a drifter whose unusual fetish of videotaping conversations about sex lives of women deconvoluted this adulterous entangle.In the biological life,persistent bias can also throw off a balance such as the homeostasis delicately constructed among metabolism,longevity,and the insulin signaling pathway.In a recent paper published in Cell Metabolism,Yong Liu’s group at the Shanghai Institute of Nutritional Sciences and Liangyou Rui’s group at the University of Michigan Medical School reported that alteration of metabolism through genetic deletion of SH2B,a gene encoding an adaptor protein required for insulin signaling,causes significant changes in the life span of affected fruitflies and mice.While the manmade and the god-made stories show only a slight superficial analogy in form,they both unfold through serendipitous analyses of seemingly unrelated events,a theme that reoccurringly underscores the importance of basic research.展开更多
Obesity,the scrooge of technological advances of the human society,just had its genetic makings revealed once again.A large international team led by Josef M.Penninger and Harald Esterbauer from the Austrian Academy o...Obesity,the scrooge of technological advances of the human society,just had its genetic makings revealed once again.A large international team led by Josef M.Penninger and Harald Esterbauer from the Austrian Academy of Sciences and Medical University of Vienna have conducted a systemic hunt for obesity genes in adult Drosophila using an ingenious design of RNAi-based screening strategy(Pospisilik et al.,2010).This study covered 78%of Drosophila genome,including 30%of genes that would otherwise cause embryonic lethality if inactivated by conventional mutations.The findings included~500 obesity genes that have their functions linked to control of differentiation along neuronal,muscle,and oenocyte lineages,but components of the Hedgehog(Hh)signaling distinguished themselves as the top-scoring hits。展开更多
The asymmetric cell division is the way in which a stem cell divides into one daughter stem cell and one differentiated daughter cell.This process is one of the key principles of developmental biology that ensures the...The asymmetric cell division is the way in which a stem cell divides into one daughter stem cell and one differentiated daughter cell.This process is one of the key principles of developmental biology that ensures the perpetual supply of stem cells while allowing a particular cell lineage to be populated.During Drosophila oogenesis,the fate of the daughter stem cell produced from the asymmetric division of germline stem cells(GSCs)is specified by Decapentaplegic(Dpp),but the other daughter cell has almost equal access to the Dpp signal.How Dpp signaling is inactivated in the differentiated daughter cell has been a deep mystery until a recent study,led by Dahua Chen of the Institute of Zoology,China(Xia et al.,2010),showed that the Dpp receptor,Thick vein(Tkv),is degraded specifically in the differentiated daughter cell by an HECT-domain ubiquitin E3 ligase,Smurf,in conjunction with a serine-threonine kinase Fused(Fu).This finding is as much revealing as it is surprising,because up until now Fu is considered a core member of the Hedgehog signaling pathway.展开更多
Interferon-γ （IFN-γ） triggers macrophage for inflammation response by activating the intracellular JAK-STAT1 signaling. Suppressor of cytokine signaling 1 （SOCS1） and protein tyrosine phosphatases can negatively...Interferon-γ （IFN-γ） triggers macrophage for inflammation response by activating the intracellular JAK-STAT1 signaling. Suppressor of cytokine signaling 1 （SOCS1） and protein tyrosine phosphatases can negatively modulate IFN-γ signaling. Here, we identify a novel negative feedback loop mediated by STAT3-SOCS3, which is tightly controlled by SENP1 via de-SUMOylation of protein tyrosine phosphatase 1B （PTPIB）, in IFN-y signaling. SENP1-deficient macrophages show defects in IFN-γ signaling and M1 macrophage activation. PTP1B in SENP1-deficient macrophages is highly SUMOylated, which reduces PTP1B-induced de-phosphorylation of STAT3. Activated STAT3 then suppresses STAT1 activation via SOCS3 induction in SENP1-deficient macro- phages. Accordingly, SENP1-deficient macrophages show reduced ability to resist Listerio rnonocytogenes infection. These results reveal a crucial role of SENP1-controlled STAT1 and STAT3 balance in rnacrophage polarization.展开更多
The landmark discoveries by Shinya Yamanaka in mice and later separately by James Thompson in humans that adult animal cells can be reprogrammed to a pluripotent state of embryonic stem(ES)cells by forced expression o...The landmark discoveries by Shinya Yamanaka in mice and later separately by James Thompson in humans that adult animal cells can be reprogrammed to a pluripotent state of embryonic stem(ES)cells by forced expression of just a few key transcription factors have permanently altered a long-held view about the stability of differentiated cells in developmental biology,and suggested a way of generating personalized replacement tissues from patients’own cells for the regenerative medical treatment.展开更多
基金supported by grant from the Natural Science Foundation of Jiangsu Province(No.BK2011140)
文摘Recent studies have revealed that osthole,an active constituent isolated from the fruit of Cnidium monnieri（L.） Cusson,a traditional Chinese medicine,possesses anticancer activity.However,its effect on breast cancer cells so far has not been elucidated clearly.In the present study,we evaluated the effects of osthole on the proliferation,cell cycle and apoptosis of human breast cancer cells MDA-MB 435.We demonstrated that osthole is effective in inhibiting the proliferation of MDA-MB 435 cells,The mitochondrion-mediated apoptotic pathway was involved in apoptosis induced by osthole,as indicated by activation of caspase-9 and caspase-3 followed by PARP degradation.The mechanism underlying its effect on the induction of G1 phase arrest was due to the up-regulation of p53 and p21 and down-regulation of Cdk2 and cyclin D1 expression.Were observed taken together,these findings suggest that the anticancer efficacy of osthole is mediated via induction of cell cycle arrest and apoptosis in human breast cancer cells and osthole may be a potential chemotherapeutic agent against human breast cancer.
文摘The development of the Wolffian/epididymal duct is crucial for proper function and, therefore, male fertility. The development of the epididymis is complex; the initial stages form as a transient embryonic kidney; then the mesonephros is formed, which in turn undergoes extensive morphogenesis under the influence of androgens and growth factors. Thus, understanding of its full development requires a wide and multidisciplinary view. This review focuses on mouse models that display abnormalities of the Wolffian duct and mesonephric development, the importance of these mouse models toward understanding male reproductive tract development, and how these models contribute to our understanding of clinical abnormalities in humans such as congenital anomalies of the kidney and urinary tract （CAKUT）.
基金supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,2014-37)
文摘Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matched paraneoplastic normal tissues, and to explore the intrinsic mechanism of OSCC development and progres- sion. We obtained the differentially expressed mRNA expression profiles in 10 pairs of fresh-frozen OSCC tissue specimens and matched paraneoplastic normal tissue specimens by high-throughput RNA sequencing. By using Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses, the functional significance of the differentially expressed genes were analyzed. We identified 1,120 sig- nificantly up-regulated mRNAs and 178 significantly down-regulated mRNAs in OSCC, compared to normal tissue. The differentially expressed mRNAs were involved in 20 biological processes and 68 signal pathways. Compared to adjacent normal tissue, the expression of MAGEAll was up-regulated; TCHH was down-regulated. These find- ings were verified by real-time PCR. These differentially expressed mRNAs may function as oncogenes or tumor suppressors in the development and progression of OSCC. This study provides novel insights into OSCC. However, further work is needed to determine if these differentially expressed mRNAs have potential roles as diagnostic bio- markers and candidate therapeutic targets for OSCC.
文摘Medulloblastoma is the most common malignant pediatric brain tumor. Some are thought to originate from cerebellar granule neuron progenitors （CGNPs） that fail to undergo normal cell cycle exit and differentiation. The contribution of microRNAs to the initiation and progression of medulloblastoma remains poorly understood. Increased expression of the miR-183-96-182 cluster of microRNAs has been noted in several aggressive sub- groups. We identified that expression of miR-183-96-182 was higher in medulloblastomas with Pten gene loss in the background of the activated sonic hedgehog （Shh） signaling pathway. Ectopic miR-183-96-182 expression in CGNPs synergized with exogenous Shh to increase proliferation and its role depended on hedgehog signaling ac- tivation. Our findings suggest a new microRNA cluster, the miR-183-96-182, functionally collaborates with the Shh signaling pathway in the development of medulloblastomas in mice.
文摘The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin （MTx）, a Ca2＋-mobilizing agent, has been shown to be a potent inducer of the mouse sperm AR, with a pharmacology similar to that of the zona pellucida （ZP）, possibly suggesting a common pathway for both inducers. Using recombinant human ZP3 （rhZP3）, mouse ZP and two MTx channel blockers （U73122 and U73343）, we investigated and compared the MTx- and ZP-induced ARs in human and mouse spermatozoa. Herein, we report that MTx induced AR and elevated intracellular Ca2＋ （[Ca2＋]~） in human spermatozoa, both of which were blocked by U73122 and U73343. These two compounds also inhibited the MTx-induced AR in mouse spermatozoa. In disagreement with our previous proposal, the AR triggered by rhZP3 or mouse ZP was not blocked by U73343, indicating that in human and mouse spermatozoa, the AR induction by the physiological ligands or by MTx occurred through distinct pathways. U73122, but not U73343 （inactive analogue）, can block phospholipase C （PLC）. Another PLC inhibitor, edelfosine, also blocked the rhZP3- and ZP-induced ARs. These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR. Notably, edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human, suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.
基金supported by the Start-up Funding of Henan University of Science and Technology(13480027) to Q. C.the Key Science Foundation of Nanjing Medical University(2015NJMUZD002)+2 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(16KJB-180020)Natural Science Foundation of Jiangsu Province (BK20171053)National Natural Science Funds of China (81702747) to C.L
文摘Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.
基金supported by the National Natural Science Foundationof China (No. 30771961 and No. 30901344)Science Development Foundation of Nanjing Medical University (No. 08NMUZ003)Jiangsu Province Laboratory of Pathogen Biology (No. 08bykf01)
文摘Apoptosis plays an important role in the pathogenesis of viral infections.In this study,we investigated the cell death processes during productive HHV-6A infection and the underlying mechanisms.Annexin V-PI staining and electron microscopy indicated that HHV-6A is a strong inducer of apoptosis.HHV-6A infection decreased mitochondrial transmembrane potential and led to morphological changes of mitochondria.The cell death was associated with activation of caspase-3 and cleavage of DNA repair enzyme poly （ADP-ribose） polymerase,which is known to be an important substrate for activated caspase-3.Caspase-9 was activated significantly in HHV-6A-infected cells,whereas caspase-8 was not activated obviously.Moreover,HHV-6A infection upregulated Bax and downregulated Bcl-2.This is the first demonstration of mitochondrion-mediated,caspase-dependent apoptosis in HHV-6A-infected cells.
文摘Constitutive hedgehog （Hh） signaling is associated with the genesis of medulloblastomas （MB）. The objective of this study is to identify special microRNAs （miRNAs） regulated by the Hh pathway, and to clarify the role of miRNAs during the genesis of MB induced by sustained Hh activation. In the primary screening, we used stemloop RT-PCR to test the expression of 90 different miRNAs in the wildtype （WT） and Ptc-/- MEF cell lines. In the secondary screening, the miRNAs screened from the first screening were validated in the Sufu-/- MEF cell lines. We then verified the expression of miRNAs both in the normal cerebellar tissues and the MB induced by activated Hh pathway, and examined the expression of the other 21 miRNA members of the miR-154 cluster in the MB and normal cerebellum. In the first screening, 13 miRNAs showed significant differential expression in WT and Ptc-/- MEF cell lines, while 10 of them had significant difference in the Sufu-/- MEF cell line. Compared to the normal mouse cerebellum, only 2 miRNAs in 15 miRNAs were differentially expressed between the MB and normal cerebellar tissues. Among 21 members of the miR-154 cluster, 6 miRNAs were downregulated in the MB. Our study demonstrated that miR-154 may be regulated by the Hh pathway, and the activation of the Hh pathway led to the downregulation of the miR-154 cluster, resulting in the genesis of MB.
文摘Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gene discs large （dig） encodes a septate junction protein functioning during epithelial polarization, asymmetric neuroblast division, and formation of neuromuscular junctions. Here, we report the role of dig in testis development and its critical function in somatic cyst cells （SCCs）. In these cells dig is primarily required for their survival and expansion, and contributes to spermatocyte cyst differentiation. Cell death primarily occurred in SCCs at the end of spermatogonial amplification at a time when Dig becomes restricted in wild-type （wt） testes to the distal somatic cells capping the growing spermatocyte cysts. RNAi depletion of dig transcripts in early SCCs fully prevented testis development, whereas depletion in late SCCs resulted in a breakdown of spermatocyte cyst structure and germ cell individualization. Specific dig expression in SCCs resulted in developmental rescue of dig mutant testes, whereas its expression in germ cells exerted no such effect, dig overexpression in wt testes led to spermatocyte cyst expansion at the expense of spermatogonial cysts. Our data demonstrate that dig is essentially required in SCCs for their survival, expansion, and differentiation, and for the encapsulation of the germline cells.
文摘In a 1989 Hollywood hit“Sex,Lies,and Videotapes”,director Steven Soderbergh told a story of an incestuous affair between a hot-shot lawyer and the sister of his married wife.An over-stayed visit by a drifter whose unusual fetish of videotaping conversations about sex lives of women deconvoluted this adulterous entangle.In the biological life,persistent bias can also throw off a balance such as the homeostasis delicately constructed among metabolism,longevity,and the insulin signaling pathway.In a recent paper published in Cell Metabolism,Yong Liu’s group at the Shanghai Institute of Nutritional Sciences and Liangyou Rui’s group at the University of Michigan Medical School reported that alteration of metabolism through genetic deletion of SH2B,a gene encoding an adaptor protein required for insulin signaling,causes significant changes in the life span of affected fruitflies and mice.While the manmade and the god-made stories show only a slight superficial analogy in form,they both unfold through serendipitous analyses of seemingly unrelated events,a theme that reoccurringly underscores the importance of basic research.
文摘Obesity,the scrooge of technological advances of the human society,just had its genetic makings revealed once again.A large international team led by Josef M.Penninger and Harald Esterbauer from the Austrian Academy of Sciences and Medical University of Vienna have conducted a systemic hunt for obesity genes in adult Drosophila using an ingenious design of RNAi-based screening strategy(Pospisilik et al.,2010).This study covered 78%of Drosophila genome,including 30%of genes that would otherwise cause embryonic lethality if inactivated by conventional mutations.The findings included~500 obesity genes that have their functions linked to control of differentiation along neuronal,muscle,and oenocyte lineages,but components of the Hedgehog(Hh)signaling distinguished themselves as the top-scoring hits。
文摘The asymmetric cell division is the way in which a stem cell divides into one daughter stem cell and one differentiated daughter cell.This process is one of the key principles of developmental biology that ensures the perpetual supply of stem cells while allowing a particular cell lineage to be populated.During Drosophila oogenesis,the fate of the daughter stem cell produced from the asymmetric division of germline stem cells(GSCs)is specified by Decapentaplegic(Dpp),but the other daughter cell has almost equal access to the Dpp signal.How Dpp signaling is inactivated in the differentiated daughter cell has been a deep mystery until a recent study,led by Dahua Chen of the Institute of Zoology,China(Xia et al.,2010),showed that the Dpp receptor,Thick vein(Tkv),is degraded specifically in the differentiated daughter cell by an HECT-domain ubiquitin E3 ligase,Smurf,in conjunction with a serine-threonine kinase Fused(Fu).This finding is as much revealing as it is surprising,because up until now Fu is considered a core member of the Hedgehog signaling pathway.
文摘Interferon-γ （IFN-γ） triggers macrophage for inflammation response by activating the intracellular JAK-STAT1 signaling. Suppressor of cytokine signaling 1 （SOCS1） and protein tyrosine phosphatases can negatively modulate IFN-γ signaling. Here, we identify a novel negative feedback loop mediated by STAT3-SOCS3, which is tightly controlled by SENP1 via de-SUMOylation of protein tyrosine phosphatase 1B （PTPIB）, in IFN-y signaling. SENP1-deficient macrophages show defects in IFN-γ signaling and M1 macrophage activation. PTP1B in SENP1-deficient macrophages is highly SUMOylated, which reduces PTP1B-induced de-phosphorylation of STAT3. Activated STAT3 then suppresses STAT1 activation via SOCS3 induction in SENP1-deficient macro- phages. Accordingly, SENP1-deficient macrophages show reduced ability to resist Listerio rnonocytogenes infection. These results reveal a crucial role of SENP1-controlled STAT1 and STAT3 balance in rnacrophage polarization.
文摘The landmark discoveries by Shinya Yamanaka in mice and later separately by James Thompson in humans that adult animal cells can be reprogrammed to a pluripotent state of embryonic stem(ES)cells by forced expression of just a few key transcription factors have permanently altered a long-held view about the stability of differentiated cells in developmental biology,and suggested a way of generating personalized replacement tissues from patients’own cells for the regenerative medical treatment.
