Neuronal polarity is involved in multiple developmental stages, including cortical neuron migration,multipolar-to-bipolar transition, axon initiation, apical/basal dendrite differentiation, and spine formation. All of...Neuronal polarity is involved in multiple developmental stages, including cortical neuron migration,multipolar-to-bipolar transition, axon initiation, apical/basal dendrite differentiation, and spine formation. All of these processes are associated with the cytoskeleton and are regulated by precise timing and by controlling gene expression. The P-Rex1(phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1) gene for example, is known to be important for cytoskeletal reorganization, cell motility, and migration. Deficiency of P-Rex1 protein leads to abnormal neuronal migration and synaptic plasticity, as well as autism-related behaviors.Nonetheless, the effects of P-Rex1 overexpression on neuronal development and higher brain functions remain unclear. In the present study, we explored the effect of P-Rex1 overexpression on cerebral development and psychosis-related behaviors in mice. In utero electroporation at embryonic day 14.5 was used to assess the influence of P-Rex1 overexpression on cell polarity and migration.Primary neuron culture was used to explore the effects of P-Rex1 overexpression on neuritogenesis and spine morphology. In addition, P-Rex1 overexpression in the medial prefrontal cortex(m PFC) of mice was used to assess psychosis-related behaviors. We found that P-Rex1 overexpression led to aberrant polarity and inhibited the multipolar-to-bipolar transition, leading to abnormal neuronal migration. In addition, P-Rex1 overexpression affected the early development of neurons, manifested as abnormal neurite initiation with cytoskeleton change,reduced the axon length and dendritic complexity, and caused excessive lamellipodia in primary neuronal culture.Moreover, P-Rex1 overexpression decreased the density of spines with increased height, width, and head area in vitro and in vivo. Behavioral tests showed that P-Rex1 overexpression in the mouse m PFC caused anxiety-like behaviors and a sensorimotor gating deficit. The appropriate P-Rex1 level plays a critical role in the developing cerebral cortex and excessive P-Rex1 might be related to psychosis-related behaviors.展开更多
In order to investigate DNA methylation profiles of five pluripotency-related genes （Oct4, Sox2, Nanog, Rexl and Fgf4） during bovine maternal to zygotic transition （MZT） in both in vitro fertilized （IVF） and nuc...In order to investigate DNA methylation profiles of five pluripotency-related genes （Oct4, Sox2, Nanog, Rexl and Fgf4） during bovine maternal to zygotic transition （MZT） in both in vitro fertilized （IVF） and nuclear transfer （NT） embryos, sodium bisulfite sequencing method was used to detect DNA methylation levels, accompanied by the statistical analysis of embryo developmental rates. The results showed that Oct4, Nanog, Rexl and Fgf4 were respectively demethylated by 25.22% （P 〈 0.01）, 3.84% （P 〉 0.05）, 31.82% （P 〈 0.01） and 10% （P 〉 0.05） while Sox2 retained unmethylafion during MZT in IVF embryos. By contrast, Oct4 and Rexl respectively underwent demethylation by 23.04% （P 〈 0.01） and 6.02% （P 〉 0.05）, and, reversely, Sox2, Nanog and Fgf4 respectively experienced remethylation by 0.84% （P 〉 0.05）, 5.39% （P 〉 0.05） and 5.46% （P 〉 0.05） during MZT in NT embryos. Interestingly, the CpG 14 site of Sox2 was specifically methylated in both 8-cell and morula NT embryos. In addition, the development of blastocysts between IVF and NT embryos showed no significant difference. DNA methylation analysis showed that only Oct4 and Sox2 underwent the correct methylation reprogramming process, which may be responsible for the development of blastocysts of NT embryos to a certain extent. In conclusion, the five genes respectively experienced demethylation to different extents and incomplete DNA methylation reprogramming during bovine MZT in both IVF and NT embryos, suggesting that they may be used as indicators for bovine embryo developmental competence.展开更多
The effect of Pr,Nd addition on the magnetic properties and magnetic exchange interaction of gadolinium alloys was systematically studied.Curie temperature TC and magnetic moment of Gd（1–x）REx（RE=Pr,Nd）systems wi...The effect of Pr,Nd addition on the magnetic properties and magnetic exchange interaction of gadolinium alloys was systematically studied.Curie temperature TC and magnetic moment of Gd（1–x）REx（RE=Pr,Nd）systems with x〈0.05 were investigated.When x〈0.05,Pr and Nd formed respectively with Gd continuous solid solution which has the crystalline structure HCP.Study on the magnetic behavior indicated that at near room temperature,the simple ferromagnetism prevailed in these two systems of alloy.The Curie temperature and magnetic moment of Gd（1–x）REx alloy decreased with RE（RE= Pr,Nd）content x increasing.The de Gennes factor of Gd（1–x）REx alloy which was associated with the exchange interaction between magnetic spin components also decreased with RE content increasing.The above results showed that the magnetic exchange interaction between magnetic atoms in gadolinium could be effectively changed by the Pr,Nd addition.展开更多
基金supported by grants from the National Natural Science Foundation of China (81730037, 81871077, and 81671363)the Beijing Municipal Science and Technology Project (Z181100001518001)the Young Elite Scientists Sponsorship Program By China Association for Science and Technology (YESS20160068)
文摘Neuronal polarity is involved in multiple developmental stages, including cortical neuron migration,multipolar-to-bipolar transition, axon initiation, apical/basal dendrite differentiation, and spine formation. All of these processes are associated with the cytoskeleton and are regulated by precise timing and by controlling gene expression. The P-Rex1(phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1) gene for example, is known to be important for cytoskeletal reorganization, cell motility, and migration. Deficiency of P-Rex1 protein leads to abnormal neuronal migration and synaptic plasticity, as well as autism-related behaviors.Nonetheless, the effects of P-Rex1 overexpression on neuronal development and higher brain functions remain unclear. In the present study, we explored the effect of P-Rex1 overexpression on cerebral development and psychosis-related behaviors in mice. In utero electroporation at embryonic day 14.5 was used to assess the influence of P-Rex1 overexpression on cell polarity and migration.Primary neuron culture was used to explore the effects of P-Rex1 overexpression on neuritogenesis and spine morphology. In addition, P-Rex1 overexpression in the medial prefrontal cortex(m PFC) of mice was used to assess psychosis-related behaviors. We found that P-Rex1 overexpression led to aberrant polarity and inhibited the multipolar-to-bipolar transition, leading to abnormal neuronal migration. In addition, P-Rex1 overexpression affected the early development of neurons, manifested as abnormal neurite initiation with cytoskeleton change,reduced the axon length and dendritic complexity, and caused excessive lamellipodia in primary neuronal culture.Moreover, P-Rex1 overexpression decreased the density of spines with increased height, width, and head area in vitro and in vivo. Behavioral tests showed that P-Rex1 overexpression in the mouse m PFC caused anxiety-like behaviors and a sensorimotor gating deficit. The appropriate P-Rex1 level plays a critical role in the developing cerebral cortex and excessive P-Rex1 might be related to psychosis-related behaviors.
基金supported by the Key Scientific and Technological Special Program for the Culture of Disease-resistance Transgenic Cattle Species(No.2008ZX08007-004),Government of China
文摘In order to investigate DNA methylation profiles of five pluripotency-related genes （Oct4, Sox2, Nanog, Rexl and Fgf4） during bovine maternal to zygotic transition （MZT） in both in vitro fertilized （IVF） and nuclear transfer （NT） embryos, sodium bisulfite sequencing method was used to detect DNA methylation levels, accompanied by the statistical analysis of embryo developmental rates. The results showed that Oct4, Nanog, Rexl and Fgf4 were respectively demethylated by 25.22% （P 〈 0.01）, 3.84% （P 〉 0.05）, 31.82% （P 〈 0.01） and 10% （P 〉 0.05） while Sox2 retained unmethylafion during MZT in IVF embryos. By contrast, Oct4 and Rexl respectively underwent demethylation by 23.04% （P 〈 0.01） and 6.02% （P 〉 0.05）, and, reversely, Sox2, Nanog and Fgf4 respectively experienced remethylation by 0.84% （P 〉 0.05）, 5.39% （P 〉 0.05） and 5.46% （P 〉 0.05） during MZT in NT embryos. Interestingly, the CpG 14 site of Sox2 was specifically methylated in both 8-cell and morula NT embryos. In addition, the development of blastocysts between IVF and NT embryos showed no significant difference. DNA methylation analysis showed that only Oct4 and Sox2 underwent the correct methylation reprogramming process, which may be responsible for the development of blastocysts of NT embryos to a certain extent. In conclusion, the five genes respectively experienced demethylation to different extents and incomplete DNA methylation reprogramming during bovine MZT in both IVF and NT embryos, suggesting that they may be used as indicators for bovine embryo developmental competence.
基金Project supported by the Key Project of National Natural Science Foundation of China(51176050)
文摘The effect of Pr,Nd addition on the magnetic properties and magnetic exchange interaction of gadolinium alloys was systematically studied.Curie temperature TC and magnetic moment of Gd（1–x）REx（RE=Pr,Nd）systems with x〈0.05 were investigated.When x〈0.05,Pr and Nd formed respectively with Gd continuous solid solution which has the crystalline structure HCP.Study on the magnetic behavior indicated that at near room temperature,the simple ferromagnetism prevailed in these two systems of alloy.The Curie temperature and magnetic moment of Gd（1–x）REx alloy decreased with RE（RE= Pr,Nd）content x increasing.The de Gennes factor of Gd（1–x）REx alloy which was associated with the exchange interaction between magnetic spin components also decreased with RE content increasing.The above results showed that the magnetic exchange interaction between magnetic atoms in gadolinium could be effectively changed by the Pr,Nd addition.
