采用基于液相色谱-高分辨质谱的转录因子结合序列串联多拷贝双联DNA结合元件(Concatenated tandem array of transcription factor response elements,catTFRE)Pull down蛋白质组学技术,研究了曲妥珠单抗耐药胃癌细胞的转录因子及其调...采用基于液相色谱-高分辨质谱的转录因子结合序列串联多拷贝双联DNA结合元件(Concatenated tandem array of transcription factor response elements,catTFRE)Pull down蛋白质组学技术,研究了曲妥珠单抗耐药胃癌细胞的转录因子及其调控作用。以合成的串联转录因子结合序列DNA片段为亲和试剂,用生物素标记,作为"DNA诱饵",通过Pull down富集后,采用液相色谱-高分辨质谱检测捕获的转录因子,基于强度定量法(Intensity based absolute quantification,iBAQ)定量,筛选出与DNA结合活性显著变化的转录因子。利用WebGestalt(2017)数据库对激活转录因子调控的信号通路、家族分类、调控网络及转录因子-靶基因(TFs-targets)进行分析。结果表明,359个转录因子被定量检测,与亲本细胞相比,61个转录因子在曲妥珠单抗耐药胃癌细胞中与DNA结合活性显著变化,其中结合活性增强48个,活性降低13个。激活转录因子属于bZIP、bHLH、homebox、HMG box、Zine finger等家族。KEGG通路富集显示,癌症、MAPK、Wnt、TGF-β、凋亡等多条通路在耐药细胞中显著改变。TFs-targets分析表明,TCF7L2、TCF7、FOXC1、JUN、CYC、FOS、ELK4、NFκB2、DDIT3和ATF2在上皮-间质转化(Epithelial-mesenchymal transformation,EMT)、Wnt、MAPK信号通路促使胃癌曲妥珠单抗耐药过程中发挥重要调控作用,提示靶向这些转录因子所调控的信号通路可能是逆转胃癌曲妥珠单抗耐药的重要途径。展开更多
Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play ...Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play a critical role in the stabilization and establishment of nascent plant polyploids as new species. To further study this issue, five wheat chromosome 7B_specific sequences, isolated from common wheat (Triticum aestivum L.) by chromosome microdissection, were characterized. The sequences were studied by genomic Southern hybridizations on a collection of polyploid wheats and their diploid progenitors. Four sequences hybridized to all polyploid species, but at the diploid level to only species closely related to the B_genome of polyploid wheat. This indicates that these sequences originated with the divergence of the diploid species, and was then vertically transmitted to polyploids. One sequence hybridized to all species at both the diploid and polyploid levels, suggesting its elimination after the polyploid wheat formation. The hybridization of this sequence to two synthetic polyploid wheats indicated that sequence elimination is a rapid event and probably related to methylation status of the sequence. Based on the above results, we suggest that selective changes of low_copy sequences occur rapidly after polyploid formation, which may contribute to the differentiation of chromosomes in newly formed allopolyploid wheats.展开更多
文摘Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play a critical role in the stabilization and establishment of nascent plant polyploids as new species. To further study this issue, five wheat chromosome 7B_specific sequences, isolated from common wheat (Triticum aestivum L.) by chromosome microdissection, were characterized. The sequences were studied by genomic Southern hybridizations on a collection of polyploid wheats and their diploid progenitors. Four sequences hybridized to all polyploid species, but at the diploid level to only species closely related to the B_genome of polyploid wheat. This indicates that these sequences originated with the divergence of the diploid species, and was then vertically transmitted to polyploids. One sequence hybridized to all species at both the diploid and polyploid levels, suggesting its elimination after the polyploid wheat formation. The hybridization of this sequence to two synthetic polyploid wheats indicated that sequence elimination is a rapid event and probably related to methylation status of the sequence. Based on the above results, we suggest that selective changes of low_copy sequences occur rapidly after polyploid formation, which may contribute to the differentiation of chromosomes in newly formed allopolyploid wheats.
