Using atom force microscopy (AFM), in vitro transcription, PAGE and other experimental technologies, it is observed that, in active genes of mice (Balb/c) nuclear DNA fragments of non-transcriptional state, only regul...Using atom force microscopy (AFM), in vitro transcription, PAGE and other experimental technologies, it is observed that, in active genes of mice (Balb/c) nuclear DNA fragments of non-transcriptional state, only regulation sequences at both ends are associated with scaffold proteins (indissociable proteins) and some transcriptional factors such as complexes (dissociable proteins) made of gene-coding proteins and specific auxiliary small molecules, while there are no combining proteins in intermediate coding sequences. However, in active genes of transcriptional state, both regulation sequences and intermediate coding sequences are associated with active transcriptional factors by non-covalent bonds.This paper shows the prospective application of AFM observation and in vitro transcription in the research on gene expression and regulation. It also offers some theoretical basis for localization of specific genes in human genomes.展开更多
Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs s...Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers.展开更多
文摘Using atom force microscopy (AFM), in vitro transcription, PAGE and other experimental technologies, it is observed that, in active genes of mice (Balb/c) nuclear DNA fragments of non-transcriptional state, only regulation sequences at both ends are associated with scaffold proteins (indissociable proteins) and some transcriptional factors such as complexes (dissociable proteins) made of gene-coding proteins and specific auxiliary small molecules, while there are no combining proteins in intermediate coding sequences. However, in active genes of transcriptional state, both regulation sequences and intermediate coding sequences are associated with active transcriptional factors by non-covalent bonds.This paper shows the prospective application of AFM observation and in vitro transcription in the research on gene expression and regulation. It also offers some theoretical basis for localization of specific genes in human genomes.
基金Supported by American Cancer Society Institutional Research to Li C,No.11-053-01-IRGNational Institutes of Health grant HL128647
文摘Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers.
文摘【目的】旨在阐明3个DSF/Rpfxoo信号系统成员RpfFxoo、RpfCxoo和RpfGxoo在水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,Xoo)毒性表达中的功能。【方法】用标记置换法缺失突变rpfFxoo、rpfCxoo和rpfGxoo基因,测定突变体及其互补菌株的DSF(diffusible signal factor)信号分子产生、胞外多糖(EPS)产生及其对水稻的致病性。【结果】从野生型菌株PXO99A基因组中克隆了推测与DSF信号生成和传导有关的基因rpfFxoo、rpfCxoo和rpfGxoo,获得了相应的单基因或双基因缺失突变体。与PXO99A产生DSF相比,ΔrpfFxoo、ΔrpfF+Cxoo和ΔrpfF+Gxoo均不产生DSF,ΔrpfCxoo过量产生,ΔrpfGxoo产量降低;rpfFxoo、rpfCxoo和rpfGxoo可以分别互补Xoo和Xcc的相应基因突变体,恢复DSF产生表型。除ΔrpfFxoo的EPS产生无明显变化外,其余突变体的均显著减少。所有突变体对水稻的致病性均显著下降。【结论】RpfFxoo、RpfCxoo和RpfGxoo调控了Xoo的DSF信号生成、EPS产生和致病性。
