[Objective] The aim was to construct the fusion expression vector of polyphosphate kinase（PPK） and green fluorescent protein（GFP） genes.[Method] In this study,the primers were designed based on PPK gene sequence（...[Objective] The aim was to construct the fusion expression vector of polyphosphate kinase（PPK） and green fluorescent protein（GFP） genes.[Method] In this study,the primers were designed based on PPK gene sequence（L03719） of E.coli DH5α in Genbank.Genomic DNA of E.coli DH 5α was extracted as template for the amplification of PPK gene by PCR method.By using In-Fusion@ HD Cloning Kit,the PPK gene was directionally cloned into NcoI site of the pCAMBIA1302 vector.[Result] Sequencing results showed that the 2.0 kb long fragment of PPK gene was inserted into the plant-based expression vector pCAMBIA1302 in front of GFP gene.[Conclusion] The fusion expression vector of PPK and GFP genes were successfully constructed.展开更多
Oncogenic H-Ras G12V and its variants have been shown to inhibit muscle differentiation. However, the role of proto-oncogenic Ras （c-Ras） in muscle differentiation remains unclear. The active GTP-bound form of Ras h...Oncogenic H-Ras G12V and its variants have been shown to inhibit muscle differentiation. However, the role of proto-oncogenic Ras （c-Ras） in muscle differentiation remains unclear. The active GTP-bound form of Ras has been known to associate with diverse effectors including Raf, phosphatidylinositol 3-kinase （PI3K）, RaI-GDS, and other molecules to transmit downstream signals. We hypothesize that c-Ras may stimulate muscle differentiation by selectively activating PI3K, an important mediator for muscle differentiation. In our experiments, inhibition of c-Ras by farnesyltransferase inhibitors and a dominant negative form of H-Ras （Ras S17N） suppressed muscle differentiation. Consistently, individual knockdown of H-Ras, K-Ras, and N-Ras by siRNAs all blocked muscle differentiation. Interestingly, we found that c-Ras preferentially interacts with PI3K rather than its major binding partner c-Raf, during myogenic differentiation, with total c-Ras activity remaining unchanged. PI3K and its downstream myogenic pathway, the Nox2/NF-kB/inducible nitric oxide synthase （iNOS） pathway, were found to be suppressed by inhibition of c-Ras activity during differentiation. Furthermore, expression of a constitutively active form of PI3K completely rescued the differentiation block and reactivated the Nox2/NF-kB/iNOS pathway in c-Ras-inhibited cells. On the ba- sis of our results, we conclude that contrary to oncogenic Ras, proto-oncogenic H-Ras, K-Ras, and N-Ras are directly involved in the promotion of muscle differentiation via PI3K and its downstream signaling pathways. In addition, PI3K pathway activation is associated with a concurrent suppression of the otherwise predominantly activated Raf/ Mek/Erk pathway.展开更多
A partial rice (Oryza sativa L.) cDNA clone. OsPMK1c, was isolated through screening of a cDNA library constructed from tillering materials. OsPI4Klc encoded a peptide of 608 amino acids with a calculated molecular ma...A partial rice (Oryza sativa L.) cDNA clone. OsPMK1c, was isolated through screening of a cDNA library constructed from tillering materials. OsPI4Klc encoded a peptide of 608 amino acids with a calculated molecular mass of 68.4 kDa. The OsPI4Klc peptide shared high homology and possessed the highly conserved domains present in most isolated cloned PI4-kinases, i.e. a lipid kinase unique (LKU) domain and a catalytic (CAT) domain. A region with similarity to pleckstrin homology (PH) domain was present in OsPI4K1c as well. Further comparison with genomic sequences in databases revealed that OsPI4K1c is located at the 3'-end of a putative rice PI 4-kinase coding gene OsPI4K1, and its coding region corresponded to the C-terminal half of OsPI4Kl protein. Twelve exons (49-562 bp in size) and 11 introns (77-974 bp in size) were identified in OsPI4K1c. The recombinant protein expressed in Escherichia coli phosphorylates phosphatidylinositol at the D4 position of the inositol ring. OsPI4K1 transcript levels were detected in a low but constitutive manner in shoot, stem, leaf, spike and root tissues and did not change upon treatment with different hormones, calcium and jasmonic acid (JA). However, treatment with salicylic acid (SA) elevated the mRNA level of the OsPI4K1 gene, which suggested the involvement of OsPI4K1 in wounding responses.展开更多
基金Supported by National Natural Science Foundation of China(31070451)Qianjiang Talent Project of Zhejiang Province(2009R10016)Zhejiang Provincial Natural Science Foundation of China(Y5110067)~~
文摘[Objective] The aim was to construct the fusion expression vector of polyphosphate kinase（PPK） and green fluorescent protein（GFP） genes.[Method] In this study,the primers were designed based on PPK gene sequence（L03719） of E.coli DH5α in Genbank.Genomic DNA of E.coli DH 5α was extracted as template for the amplification of PPK gene by PCR method.By using In-Fusion@ HD Cloning Kit,the PPK gene was directionally cloned into NcoI site of the pCAMBIA1302 vector.[Result] Sequencing results showed that the 2.0 kb long fragment of PPK gene was inserted into the plant-based expression vector pCAMBIA1302 in front of GFP gene.[Conclusion] The fusion expression vector of PPK and GFP genes were successfully constructed.
文摘Oncogenic H-Ras G12V and its variants have been shown to inhibit muscle differentiation. However, the role of proto-oncogenic Ras （c-Ras） in muscle differentiation remains unclear. The active GTP-bound form of Ras has been known to associate with diverse effectors including Raf, phosphatidylinositol 3-kinase （PI3K）, RaI-GDS, and other molecules to transmit downstream signals. We hypothesize that c-Ras may stimulate muscle differentiation by selectively activating PI3K, an important mediator for muscle differentiation. In our experiments, inhibition of c-Ras by farnesyltransferase inhibitors and a dominant negative form of H-Ras （Ras S17N） suppressed muscle differentiation. Consistently, individual knockdown of H-Ras, K-Ras, and N-Ras by siRNAs all blocked muscle differentiation. Interestingly, we found that c-Ras preferentially interacts with PI3K rather than its major binding partner c-Raf, during myogenic differentiation, with total c-Ras activity remaining unchanged. PI3K and its downstream myogenic pathway, the Nox2/NF-kB/inducible nitric oxide synthase （iNOS） pathway, were found to be suppressed by inhibition of c-Ras activity during differentiation. Furthermore, expression of a constitutively active form of PI3K completely rescued the differentiation block and reactivated the Nox2/NF-kB/iNOS pathway in c-Ras-inhibited cells. On the ba- sis of our results, we conclude that contrary to oncogenic Ras, proto-oncogenic H-Ras, K-Ras, and N-Ras are directly involved in the promotion of muscle differentiation via PI3K and its downstream signaling pathways. In addition, PI3K pathway activation is associated with a concurrent suppression of the otherwise predominantly activated Raf/ Mek/Erk pathway.
文摘A partial rice (Oryza sativa L.) cDNA clone. OsPMK1c, was isolated through screening of a cDNA library constructed from tillering materials. OsPI4Klc encoded a peptide of 608 amino acids with a calculated molecular mass of 68.4 kDa. The OsPI4Klc peptide shared high homology and possessed the highly conserved domains present in most isolated cloned PI4-kinases, i.e. a lipid kinase unique (LKU) domain and a catalytic (CAT) domain. A region with similarity to pleckstrin homology (PH) domain was present in OsPI4K1c as well. Further comparison with genomic sequences in databases revealed that OsPI4K1c is located at the 3'-end of a putative rice PI 4-kinase coding gene OsPI4K1, and its coding region corresponded to the C-terminal half of OsPI4Kl protein. Twelve exons (49-562 bp in size) and 11 introns (77-974 bp in size) were identified in OsPI4K1c. The recombinant protein expressed in Escherichia coli phosphorylates phosphatidylinositol at the D4 position of the inositol ring. OsPI4K1 transcript levels were detected in a low but constitutive manner in shoot, stem, leaf, spike and root tissues and did not change upon treatment with different hormones, calcium and jasmonic acid (JA). However, treatment with salicylic acid (SA) elevated the mRNA level of the OsPI4K1 gene, which suggested the involvement of OsPI4K1 in wounding responses.
