新一代转基因植物研究进展

转基因植物具有抗病、抗虫、抗逆、高产、营养成分改善等优良性状 ,但其安全性引起了人们的关注。新一代植物转基因技术 ,如叶绿体基因工程、基因约束、多基因共转、去除抗性标记基因、对外源基因进行实时监控、抗性管理策略、最小程度地改变基因等技术的发展 ,将使未来的转基因植物更好地适应人们的需求 。

Palmitate induces fat accumulation by activating C/EBPβ-mediated G0S2 expression in HepG2 cells

AIM To determine the role of G0/G1 switch gene 2(G0 S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation.METHODS Hep G2 cells were treated with palmitate,or palmitate in combination with CCAAT/enhancer binding protein(C/EBP)β si RNA or G0 S2 si RNA. The m RNA expression of C/EBPβ,peroxisome proliferator-activated receptor(PPAR)γ and PPARγ target genes(G0 S2,GPR81,GPR109 A and Adipoq) was examined by q PCR. The protein expression of C/EBPβ,PPARγ,and G0 S2 was determined by Western blotting. Lipid accumulation was detected with Oil Red O staining and quantified by absorbance value of the extracted Oil Red O dye. Lipolysis was evaluated by measuring the amount of glycerol released into the medium. RESULTS Palmitate caused a dose-dependent increase in lipid accumulation and a dose-dependent decrease in lipolysis in Hep G2 cells. In addition,palmitate increased the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(G0 S2,GPR81,GPR109 A,and Adipoq) and the protein expression of C/EBPβ,PPARγ,and G0 S2 in a dose-dependent manner. Knockdown of C/EBPβ decreased palmitate-induced PPARγ and its target genes(G0 S2,GPR81,GPR109 A,and Adipoq) m RNA expression and palmitate-induced PPARγ and G0 S2 protein expression in Hep G2 cells. Knockdown of C/EBPβ also attenuated lipid accumulation and augmented lipolysis in palmitate-treated Hep G2 cells. G0 S2 knockdown attenuated lipid accumulation and augmented lipolysis,while G0 S2 knockdown had no effects on the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(GPR81,GPR109 A and Adipoq) in palmitate-treated Hep G2 cells. CONCLUSION Palmitate can induce lipid accumulation in Hep G2 cells by activating C/EBPβ-mediated G0 S2 expression.

Molecular Characterization and Expression and DNA Methylation Analyses of a Galectin-Related Protein Gene from Cynoglossus semilaevis

Galectins, a family of β-galactoside-binding proteins, participate in both innate immunity and adaptive immunity. This study identified one novel galectin-related protein from half-smooth tongue sole Cynoglossus semilaevis, which was designated as CsGRP. The full-length cDNA of its encoding gene was 785 bp in length with a 528 bp open reading frame encoding a putative protein of 176 amino acids. The deduced CsGRP contained a putative 131-aa galactoside-binding lectin domain and 3 critical residues responsible for carbohydrate binding （R93, W109 and R114）. Genomic structural analysis revealed that CsGRP consisted of five exons and four intzons. CsGRP showed 68% similarity with Poecilia latipinna GRP and 67% similarity wih Stegastes partitus GRP. CsGRP showed the highest expression level in liver, although its expression was detected in all tested tissues. When challenged with Vibrio harveyi, the expression of CsGRP was significantly down-regulated in liver （P〈 0.05）. In addition, we found that in spleen and kidney of C. semilaevis, the CpG island of CsGRP showed significantly higher （P 〈 0.05） methylation level in disease-resistant family of C. semilaevis （DR-Cs） than in disease-susceptible ones （DS-Cs）. Our results suggested that CsGRP may play important roles in the immune response of C. semilaevis. Moreover, DNA methylation patterns provided valuable data for understanding the relationship between epigenetic regulation and immunity, which would assist the animal genetic research and improve the animal breeding in the future.