Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUS...Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUSCHEL （WUS）/PLANT GROWTH ACTIVATOR6 （PGA6）, BABY BOOM, LEAFY COTYLEDON1 （LEC1）, and LEC2, is able to cause vegetative-to-embryonic transition or the formation of somatic embryos. Here, we report that a gain-offunction mutation in the Arabidopsis PGA37 gene, encoding the MYBI18 transcription factor, induced vegetative-toembryonic transition, the formation of somatic embryos from root explants, and an elevated LEC1 expression level. Double mutant analysis showed that WUS was not required for induction of somatic embryos by PGA37/MYB118. In addition, overexpression of MYBll5, a homolog of PGA37/MYB118, caused a pga37-like phenotype. A myb118 myb115 double mutant did not show apparent developmental abnormalities. Collectively, these results suggest that PGA37/ MYB118 and MYB115 promote vegetative-to-embryonic transition, through a signaling pathway independent of WUS.展开更多
DDX3X is a highly conserved DEAD-box RNA helicase that participates in RNA transcription, RNA splicing, and mRNA transport, translation, and nucleo-cytoplasmic transport. It is highly expressed in metaphase II （MII）...DDX3X is a highly conserved DEAD-box RNA helicase that participates in RNA transcription, RNA splicing, and mRNA transport, translation, and nucleo-cytoplasmic transport. It is highly expressed in metaphase II （MII） oocytes and is the predominant DDX3 variant in the ovary and embryo. However, whether it is important in mouse early embryo development remains unknown. In this study, we investigated the function of DDX3X in early embryogenesis by cytoplasmic microinjection with its siRNA in zygotes or single blastomeres of 2-cell embryos. Our results showed that knockdown of Ddx3x in zygote cytoplasm led to dramatically diminished blastocyst formarion, reduced cell numbers, and an increase in the number of apoptotic cells in blastocysts. Meanwhile, there was an accumulation of p53 in RNAi blastocysts. In addition, the ratio of cell cycle arrest during 2-cell to 4-cell transition increased following microinjection of Ddx3x siRNA into single blastomeres of 2-cell embryos compared with control. These results suggest that Ddx3x is an essential gene associated with cell survival and cell cycle control in mouse early embryos, and thus plays key roles in normal embryo development.展开更多
Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse em...Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR.TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then wedetermined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. Wefound a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cellsfrom E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed inthe granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin develop-ment provided several morphological evidences for the epidermal differentiation. The above findings suggest that theexpression of TGM3 plays a important role in the epidermis differentiation in embryogenesis.展开更多
Embryo implantation is a complicated physiological process tightly regulated by multiple biological molecules including growth factors.Transforming growth factor-betas(TGF-βs)and their most specific signal transducti...Embryo implantation is a complicated physiological process tightly regulated by multiple biological molecules including growth factors.Transforming growth factor-betas(TGF-βs)and their most specific signal transduction factors,Smads,are expressed in the endometrium during the window of implantation.Recent researches indicated that Smad dependent TGF-β signaling may play an important role in the process of embryo implantation.In this study,we measured the expression of TGF-β1,TGF-β receptor type I(TpRI),Smad3 and p-Smad3 in the endometrium of mice and observed their elevation on day 4,5 and 6 of pseudopregnancy.Then we administrated a specific Smad3 inhibitor(Sis3)into the uterine cavity of mice on day 3 of pregnancy.The results showed a reduction in insulin-like growth factor-1(IGFBP-1)expression and the decreased number of implanted embryo after the administration.In addition,Sis3 was found to reduce the IGFBP-1 secretion in decidualized endometrial stromal cells.Taken all together,our findings demonstrated that TGF-β/Smad3 signaling is involved in the process of embryo implantation.展开更多
RNA polymerase （Pol） Ⅱ transcription persists in TATA-box-binding protein （TBP）^-/- mutant mouse embryos, indicating TBP-independent mechanisms for Pol Ⅱ transcription in early development. TBP-related factor 3 ...RNA polymerase （Pol） Ⅱ transcription persists in TATA-box-binding protein （TBP）^-/- mutant mouse embryos, indicating TBP-independent mechanisms for Pol Ⅱ transcription in early development. TBP-related factor 3 （TRF3） has been proposed to substitute for TBP in TBP^-/- mouse embryos. We examined the expression of TRF3 in maturing oocytes and early embryos and found that TRF3 was co-expressed with TBP in the meiotic oocytes and early embryos from the late one-cell stage onward. The amounts of TBP and TRF3 changed dynamically and correlated well with transcriptional activity. Chromatin immunoprecipitation （CHIP） assay revealed that different gene promoters in mouse embryonic stem （ES） cells recruited TRF3 and TBP selectively. Comparative analyses of TRF3 and TBP during cell cycle showed that both factors proceeded through cell cycle in a similar pace, except that TRF3 was slightly delayed than TBP in entering the nucleus when cells were exiting the M-phase. Data from expression and biochemical analyses therefore support the hypothesis that TRF3 plays a role in early mouse development. In addition, results from co-localization study suggest that TRF3 may be also involved in Pol Ⅰ transcription.展开更多
BACKGROUND： Cell culture in vitro trials have demonstrated that neurotrophin-3 （NT-3） can enhance the survival of sensory neurons and sympathetic neurons, and can also support embryo-derived motor neurons. This eff...BACKGROUND： Cell culture in vitro trials have demonstrated that neurotrophin-3 （NT-3） can enhance the survival of sensory neurons and sympathetic neurons, and can also support embryo-derived motor neurons. This effect is dependent on nerve growth factor on the surface of cells. Understanding the role of NT-3 and its receptor in the early development of human embryonic brains will help to investigate the correlation between early survival of nerve cells and the microenvironment of neural regeneration. OBJECTIVE： To observe the proliferation of cerebral neurons in the development of human embryonic brain, and to investigate the location, expression and distribution of NT-3 and its receptor TrkC during human brain development. DESIGN, TIME AND SETTING： An observation study on cells was performed in the Department of ttuman Anatomy, Histology and Embryology, Chengdu Medical College in September 2007. MATERIALS： Fifteen specimens of flesh human embryo, aged 6 weeks, were used in this study. METHODS： The proliferation of cerebral neurons was detected using proliferating cell nuclear antigen, and the immunocytochemistry ABC technique was applied to observe the location, expression and distribution of NT-3 and its receptor TrkC in the brain of the human embryo. MAIN OUTCOME MEASURES： Location, expression and distribution of NT-3 and its receptor in the brain of the human embryo. RESULTS： In the early period （aged 6 weeks） of human embryonic development, proliferating cell nuclear antigen-positive reactive substances were mainly observed in the nucleus of the forebrain ventricular zone and subventricular zone, and the intensity was stronger in the subventricular zone than the forebrain ventricle. NT-3 positive reactive substance was mainly distributed in the cytoblastema of the forebrain neuroepithelial layer and nerve cell process, while TrkC was mainly distributed in the cell membrane of the forebrain ventricular zone and subventricular zone. During embryonic development, NT-3 and TrkC showed a positive immune reaction to a greater or lesser extent in ependymal epithelium. CONCLUSION： During early human embryonic development, cerebral nerve cells proliferate in the ventricular zone and subventricular zone, and NT-3 is expressed in the neural axon. The results show that the highly expressed NT-3 could promote the proliferation of neural axons and maintain the neuron body＇s survival.展开更多
The degradation of lipids was mainly responsible for the reduction of rice quality and production of stale flavor during its storage. It was proved that LOX-3, the major component of the isozymes accounting for 80% - ...The degradation of lipids was mainly responsible for the reduction of rice quality and production of stale flavor during its storage. It was proved that LOX-3, the major component of the isozymes accounting for 80% - 90% of total activity, was the key enzyme in above process. Further results indicated that the lack of LOX-3 in Daw Dam led to decrease of lipid peroxidation, alleviating the accumulation of stale flavor during storage, which is caused by hexanal, pentanal and pentanol compounds etc. Genetic survey displayed that the absence of LOX-3 was controlled by a single Mendelian recessive gene. On the other hand, three cloned LOX genes and deduced LOX genes encoding some purified LOXs could not be contributed to the embryo LOX genes by comparing biochemical characterizations of these expressed products and some purified LOXs with known LOXs in rice embryos. The future research should focus on the further influences of LOX-3-null on rice storability. Meanwhile, single-base-trans version in coding region, insertion, deletion and replacement in promoter of LOX genes were related with lipoxygenase-null genotype of soybean and pea. Therefore, the cloning of the recessive gene controlling the null of LOX-3 and its corresponding dominant gene in rice seed embryos will contribute to the understanding of the null molecular mechanism, elucidating the differences of LOX genes expression and regulation in rice embryos. In the last, the breeding strategy of new storable rice, including the theoretical and practical concepts, was surveyed.展开更多
文摘Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUSCHEL （WUS）/PLANT GROWTH ACTIVATOR6 （PGA6）, BABY BOOM, LEAFY COTYLEDON1 （LEC1）, and LEC2, is able to cause vegetative-to-embryonic transition or the formation of somatic embryos. Here, we report that a gain-offunction mutation in the Arabidopsis PGA37 gene, encoding the MYBI18 transcription factor, induced vegetative-toembryonic transition, the formation of somatic embryos from root explants, and an elevated LEC1 expression level. Double mutant analysis showed that WUS was not required for induction of somatic embryos by PGA37/MYB118. In addition, overexpression of MYBll5, a homolog of PGA37/MYB118, caused a pga37-like phenotype. A myb118 myb115 double mutant did not show apparent developmental abnormalities. Collectively, these results suggest that PGA37/ MYB118 and MYB115 promote vegetative-to-embryonic transition, through a signaling pathway independent of WUS.
文摘DDX3X is a highly conserved DEAD-box RNA helicase that participates in RNA transcription, RNA splicing, and mRNA transport, translation, and nucleo-cytoplasmic transport. It is highly expressed in metaphase II （MII） oocytes and is the predominant DDX3 variant in the ovary and embryo. However, whether it is important in mouse early embryo development remains unknown. In this study, we investigated the function of DDX3X in early embryogenesis by cytoplasmic microinjection with its siRNA in zygotes or single blastomeres of 2-cell embryos. Our results showed that knockdown of Ddx3x in zygote cytoplasm led to dramatically diminished blastocyst formarion, reduced cell numbers, and an increase in the number of apoptotic cells in blastocysts. Meanwhile, there was an accumulation of p53 in RNAi blastocysts. In addition, the ratio of cell cycle arrest during 2-cell to 4-cell transition increased following microinjection of Ddx3x siRNA into single blastomeres of 2-cell embryos compared with control. These results suggest that Ddx3x is an essential gene associated with cell survival and cell cycle control in mouse early embryos, and thus plays key roles in normal embryo development.
基金This work was supported by Major State Basic Research Development program of China(2004CB518604)the National High Technology Research and Development Program of China(2004AA231041)the National Natural Science Foundation of China(30425027).
文摘Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR.TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then wedetermined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. Wefound a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cellsfrom E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed inthe granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin develop-ment provided several morphological evidences for the epidermal differentiation. The above findings suggest that theexpression of TGM3 plays a important role in the epidermis differentiation in embryogenesis.
基金the National Natural Science Foundation of China(No.81701450).
文摘Embryo implantation is a complicated physiological process tightly regulated by multiple biological molecules including growth factors.Transforming growth factor-betas(TGF-βs)and their most specific signal transduction factors,Smads,are expressed in the endometrium during the window of implantation.Recent researches indicated that Smad dependent TGF-β signaling may play an important role in the process of embryo implantation.In this study,we measured the expression of TGF-β1,TGF-β receptor type I(TpRI),Smad3 and p-Smad3 in the endometrium of mice and observed their elevation on day 4,5 and 6 of pseudopregnancy.Then we administrated a specific Smad3 inhibitor(Sis3)into the uterine cavity of mice on day 3 of pregnancy.The results showed a reduction in insulin-like growth factor-1(IGFBP-1)expression and the decreased number of implanted embryo after the administration.In addition,Sis3 was found to reduce the IGFBP-1 secretion in decidualized endometrial stromal cells.Taken all together,our findings demonstrated that TGF-β/Smad3 signaling is involved in the process of embryo implantation.
基金This study was supported by grants from National Basic Research Program of China （973 Program） （Nos. 001CB509903 and 001CB509904）Hi-Tech Research and Development Program of China （863 Program） （Nos. 2001AA216121 and 2004AA205010）+3 种基金 National Natural Science Foundation of China （No. 30040003） Science and Technology Committee of Shanghai Municipality （Nos. 99DJ14002, 00DJ1 4033, 01DJ14003, and 03DJ14017） Chinese Academy of Science （No. KSCX-2-3-08）Shanghai Municipal Education Commission and Shanghai Jiao Tong University, School of Medicine.
文摘RNA polymerase （Pol） Ⅱ transcription persists in TATA-box-binding protein （TBP）^-/- mutant mouse embryos, indicating TBP-independent mechanisms for Pol Ⅱ transcription in early development. TBP-related factor 3 （TRF3） has been proposed to substitute for TBP in TBP^-/- mouse embryos. We examined the expression of TRF3 in maturing oocytes and early embryos and found that TRF3 was co-expressed with TBP in the meiotic oocytes and early embryos from the late one-cell stage onward. The amounts of TBP and TRF3 changed dynamically and correlated well with transcriptional activity. Chromatin immunoprecipitation （CHIP） assay revealed that different gene promoters in mouse embryonic stem （ES） cells recruited TRF3 and TBP selectively. Comparative analyses of TRF3 and TBP during cell cycle showed that both factors proceeded through cell cycle in a similar pace, except that TRF3 was slightly delayed than TBP in entering the nucleus when cells were exiting the M-phase. Data from expression and biochemical analyses therefore support the hypothesis that TRF3 plays a role in early mouse development. In addition, results from co-localization study suggest that TRF3 may be also involved in Pol Ⅰ transcription.
文摘BACKGROUND： Cell culture in vitro trials have demonstrated that neurotrophin-3 （NT-3） can enhance the survival of sensory neurons and sympathetic neurons, and can also support embryo-derived motor neurons. This effect is dependent on nerve growth factor on the surface of cells. Understanding the role of NT-3 and its receptor in the early development of human embryonic brains will help to investigate the correlation between early survival of nerve cells and the microenvironment of neural regeneration. OBJECTIVE： To observe the proliferation of cerebral neurons in the development of human embryonic brain, and to investigate the location, expression and distribution of NT-3 and its receptor TrkC during human brain development. DESIGN, TIME AND SETTING： An observation study on cells was performed in the Department of ttuman Anatomy, Histology and Embryology, Chengdu Medical College in September 2007. MATERIALS： Fifteen specimens of flesh human embryo, aged 6 weeks, were used in this study. METHODS： The proliferation of cerebral neurons was detected using proliferating cell nuclear antigen, and the immunocytochemistry ABC technique was applied to observe the location, expression and distribution of NT-3 and its receptor TrkC in the brain of the human embryo. MAIN OUTCOME MEASURES： Location, expression and distribution of NT-3 and its receptor in the brain of the human embryo. RESULTS： In the early period （aged 6 weeks） of human embryonic development, proliferating cell nuclear antigen-positive reactive substances were mainly observed in the nucleus of the forebrain ventricular zone and subventricular zone, and the intensity was stronger in the subventricular zone than the forebrain ventricle. NT-3 positive reactive substance was mainly distributed in the cytoblastema of the forebrain neuroepithelial layer and nerve cell process, while TrkC was mainly distributed in the cell membrane of the forebrain ventricular zone and subventricular zone. During embryonic development, NT-3 and TrkC showed a positive immune reaction to a greater or lesser extent in ependymal epithelium. CONCLUSION： During early human embryonic development, cerebral nerve cells proliferate in the ventricular zone and subventricular zone, and NT-3 is expressed in the neural axon. The results show that the highly expressed NT-3 could promote the proliferation of neural axons and maintain the neuron body＇s survival.
基金supported by the Transgenic Project of the Ministry of Science and Technology(J00-A006-1)the“948”project of the Ministry of Agricuture of China(201002A)。
文摘The degradation of lipids was mainly responsible for the reduction of rice quality and production of stale flavor during its storage. It was proved that LOX-3, the major component of the isozymes accounting for 80% - 90% of total activity, was the key enzyme in above process. Further results indicated that the lack of LOX-3 in Daw Dam led to decrease of lipid peroxidation, alleviating the accumulation of stale flavor during storage, which is caused by hexanal, pentanal and pentanol compounds etc. Genetic survey displayed that the absence of LOX-3 was controlled by a single Mendelian recessive gene. On the other hand, three cloned LOX genes and deduced LOX genes encoding some purified LOXs could not be contributed to the embryo LOX genes by comparing biochemical characterizations of these expressed products and some purified LOXs with known LOXs in rice embryos. The future research should focus on the further influences of LOX-3-null on rice storability. Meanwhile, single-base-trans version in coding region, insertion, deletion and replacement in promoter of LOX genes were related with lipoxygenase-null genotype of soybean and pea. Therefore, the cloning of the recessive gene controlling the null of LOX-3 and its corresponding dominant gene in rice seed embryos will contribute to the understanding of the null molecular mechanism, elucidating the differences of LOX genes expression and regulation in rice embryos. In the last, the breeding strategy of new storable rice, including the theoretical and practical concepts, was surveyed.
