Showing papers on "Demethylase published in 2002"
TL;DR: This is the first complete and detailed analysis of the epigenetic reprogramming cycle during preimplantation development and shows that demethylation of the male pronucleus is completed within 4 h of fertilisation.
1,218 citations
TL;DR: It is proposed that a single protein possessing both repressor and demethylase functions has evolved to coordinate a program that requires suppression of some methylated genes and activation of others.
185 citations
TL;DR: Insight is provided into the mechanism regulating the transcription of the uPA gene in the complex multistep process of breast cancer progression by suggesting the combination of increased DNA methyltransferase activity with reduced demethylase activity contributes to the methylation and silencing of uPA expression in MCF-7 cells.
127 citations
TL;DR: It is suggested that TnpA binds to the postreplicative, hemimethylated Spm sequence and promotes dem methylation either by creating an appropriate demethylation substrate or by itself participating in or recruiting a demethylase.
Abstract: Heritable epigenetic inactivation of the maize Suppressor-mutator (Spm) transposon is associated with promoter methylation, and its reversal is mediated by the transposon-encoded TnpA protein. We have developed an assay that permits demethylation of the Spm sequence to be controlled by inducing the expression of TnpA in plant cells. Using this assay, we show that demethylation is a rapid, active process. TnpA is a weak transcriptional activator, and deletions that abolish its transcriptional activity also eliminate its demethylation activity. We show that cell cycle and DNA synthesis inhibitors interfere with TnpA-mediated Spm demethylation. We further show that TnpA has a much lower affinity for fully methylated than for hemimethylated or unmethylated DNA fragments derived from Spm termini. Based on these observations, we suggest that TnpA binds to the postreplicative, hemimethylated Spm sequence and promotes demethylation either by creating an appropriate demethylation substrate or by itself participating in or recruiting a demethylase.
51 citations
TL;DR: It is proposed that the lack of a coordinate transcriptional control over the cholesterol biosynthetic pathway contributes importantly to overproduction of the signaling sterol T-MAS in testis.
42 citations
15 Jul 2002
TL;DR: 目的研究国内临床耐氟康唑白念珠菌的吡咯类药物作用靶酶--细胞色素P-450羊毛固醇14-α脱甲基 酶
Abstract: 目的研究国内临床耐氟康唑白念珠菌的吡咯类药物作用靶酶--细胞色素P-450羊毛固醇14-α脱甲基酶的基因ERG11突变. 方法用酶消化和碱裂解法抽提基因组DNA,PCR扩增ERG11基因的读码框片段,将目的片段与PBS载体(Bluscript M13)连接,重组体转入DH5α中,从而测定序列. 结果在15株耐药菌中共发现了12个有义点突变、17个无义点突变和一个菌株的部分移码.12个有义点突变的氨基酸变异是F72L、D81G、D116E、K128T、Y132H、E266D、D294G、S361P、M374V、P386L、H400R和Q474K,突变主要靠近羧基端;而敏感株的氨基酸变异为F72L、K128T和E266D,靠近氨基端.耐药株的D294G、S361P、M374V、P386L、H400R和Q474K氨基酸变异与文献报道不同.结论耐药株和敏感株的点突变不同, D294G、S361P、M374V、P386L、H400R和Q474K变异位点可能与耐药性有关,做整段编码基因的功能表达,有助于明确变异与耐药的关系.
4 citations
Journal Article•
TL;DR: It is suggested that the drug resistance is related with by the newly found alterations, including D294G, S361P, M374V, P386L, H400R, Q474K, and a frameshift.
Abstract: Objective To investigate the point mutation of the open reading frame of cytochrome P-450 lanosterol 14-α demethylase gene ERG11 Methods In order to identify such alterations, the DNA was extracted by enzyme lysis methods and the PCR was performed The PCR products were purified and cloned into PBS vector, then transformed into DH5α and sequenced Results Twenty nine point mutations were identified in this 15 resistant isolates, most of which were different from susceptible strains The mutations included 12 missense substitutions: F72L, D81G, D116E, K128T, Y132H, E266D, D294G, S361P, M374V, P386L, H400R, and Q474K, of which 6 had not been described previously (D294G, S361P, M374V, P386L, H400R, and Q474K) The other mutations included a frameshift, and 17 silent mutations Conclusions The point mutation of resistant isolate is different from that of the susceptible isolate It is suggested that the drug resistance is related with by the newly found alterations, including D294G, S361P, M374V, P386L, H400R, Q474K, and a frameshift
4 citations