Search

The TET2 DNA dioxygenase regulates gene expression by catalyzing demethylation of 5-methylcytosine, thus epigenetically modulating the genome. TET2 does not contain a sequence-specific DNA-binding domain, and how it is recruited to specific genomic sites is not fully understood. Here we carried out a mammalian two-hybrid screen and identified multiple transcriptional regulators potentially interacting with TET2. The SMAD nuclear interacting protein 1 (SNIP1) physically interacts with TET2 and bridges TET2 to bind several transcription factors, including c-MYC. SNIP1 recruits TET2 to the promoters of c-MYC target genes, including those involved in DNA damage response and cell viability. TET2 protects cells from DNA damage-induced apoptosis dependending on SNIP1. Our observations uncover a mechanism for targeting TET2 to specific promoters through a ternary interaction with a co-activator and many sequence-specific DNA-binding factors. This study also reveals a TET2-SNIP1-c-MYC pathway in mediating DNA damage response, thereby connecting epigenetic control to maintenance of genome stability.

A new synthetic route to peptide isocyanates and isothiocyanates is introduced. The procedure involves treating the hydrochloride salts of peptides with a phosgene solution in toluene and pyridine in methylene chloride at zero degree Celsius. Modified Schotten-Baumann conditions were also employed to obtain good yields and eliminate hydantoins and other side products formed via the N-acylation of amide groups.

Background: Neuroendocrine tumors (NETs) rarely occur in the mediastinum and their etiology and pathogenesis are still unclear. Objectives: This study assessed inherited or de novo mutations in familial mediastinal NETs. Method: DNA samples from 4 patients were subjected to the whole-exome sequencing, and Sanger sequencing was used to identify Deleted in malignant brain tumor 1 (DMBT1) mutations in all 45 family members. Results: All patients showed a germline DMBT1 mutation at 4971C. Sanger sequencing data showed that 4 NETs and 2 carriers in the first patient's family and 2 NETs and 4 carriers in the second patient's family, respectively, had this DMBT1 mutation. The in vitro data showed that the ectopic expression of DMBT1 reduced tumor cell viability and migration by arresting the G1/S phase of the cell cycle. Conclusions: We identified a germline missense mutation in DMBT1D1657E as a susceptibility gene for familial mediastinal NETs. [ABSTRACT FROM AUTHOR]

Effect of low-concentration ciprofloxacin (CIP) on nitrification and nitrifying microorganisms of biofilms was studied in biological aerated filters (BAF). Quantitative PCR (qPCR) was used to determine the abundance variance of four ciprofloxacin resistance genes (CIP-ARGs) during nitrification in biofilms. The correlations between the abundances of CIP-ARGs and nitrifying microorganisms were also discussed. The results showed that CIP had little influence on the ammonium oxidation process of biofilm microorganisms, whereas inhibition of the nitrite oxidation process was found. The quantitative results of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) including Nitrobacter and Nitrospira indicated that the inhibition on the transformation of nitrite was resulted from the inhibition on Nitrobacter and Nitrospira. In addition, little influence of CIP on the relative abundance of aac and qepA in biofilms was found, but the influence on parC and oqxB was great. The abundance of Nitrotacter exhibited significant positive correlation with the abundance of parC. Similar significant correlation was also found between the abundances of Nitrospira and oqxB. It could be speculated that the genetic elements of different nitrifying microorganisms in biofilms possibly carried CIP-ARGs.

Occurrence and distribution of twelve pharmaceutical and personal care products (PPCPs) were investigated in a sewage treatment plant in Shanghai using solid-phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). Quantitative PCR (qPCR) was used to determine the distribution and removal of seven erythromycin resistance genes (ERY-ARGs). The results showed that five PPCPs including sulfamethoxazole, erythromycin, tetracycline, carbamazepine and triclosan were detected in the collected wastewater samples with concentrations in the ranges of 24.5- 38.7, 47.5-49.2, 43.1-85.4, 2.5-3.9 and 423.2-8 973.3 ng x L(-1), respectively. During the wastewater treatment process, a significant reduction of triclosan was observed, but the removal efficiencies for the other detected PPCPs were relatively low. Additionally, all target ERY-ARGs were detected in the wastewater samples ranging from 9.28 x 10(3) (ermA) to 1.83 x 10(8) (ereA) copies x L(-1) in raw influent. Though significant reductions (1.19 log-3.97 log) of ERY-ARGs were obtained, their concentrations found in the final effluent were still high. Moreover, the concentration of ERY-ARGs exhibited significant positive correlation with the concentration of erythromycin and triclosan (P < 0.05), respectively, elucidating that erythromycin played an important role in the occurrence and spread of ERY-ARGs, while triclosan may confer cross-selection for ERY-ARGs.

Background & Objective: Notch signal transduction pathway mediates cell differentiation and proliferation. Its dysfunction is supposed to be involved in tumorigenesis and development. This study was to construct a course recombination enzyme(CRE)-dependent short hairpin RNA (shRNA) expression plasmid targeting Notch1, and investigate its effect on proliferation of cervical cancer cell line HeLa., Methods: RNA interfering vectors pSico and pSicoR were used to construct CRE-dependent shRNA expression plasmids targeting GAPDH and Notch1; pBS185-CRE was used as an expression vector of CRE. HeLa cells were divided into 4 groups and transfected with pSico, pSico/CRE, pSicoR, and pSicoR/CRE, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were carried out to assess the efficiency of RNA interference (RNAi), and intracellular Notch signal level was tested by CBF-1 reporter plasmid. The proliferation of HeLa cells after CRE-dependent Notch1 RNAi was detected by MTS assay., Results: After transfection of pSico (R)-GAPDH and pSico (R)-Notch1, CRE-dependent green fluorescent cells were detected; Notch1 expression was inhibited; intracellular Notch1 signal level was decreased; the proliferation of HeLa cells was suppressed., Conclusion: RNAi of Notch1 mediated by CRE-dependent shRNA expression plasmid can down-regulate intracellular Notch1 signal level and suppress the proliferation of HeLa cells.