SummaryTET enzymes including TET1, 2 and 3 convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC)1 and regulate gene transcription2-5. However, this molecular mechanism by which TET family enzymes regulate gene transcription remains elusive5-6. Here, using protein affinity purification, we searched for functional partners of TET proteins, and found that TET2 and TET3 associate with OGT, an enzyme that by itself catalyzes O-GlcNAcylation in vivo7-8. TET2 directly interacts with OGT, which is important for the chromatin association of OGT in vivo. Although this specific interaction does not regulate the enzymatic activity of TET2, it facilitates OGT-dependent histone O-GlcNAcylation. Moreover, OGT associates with TET2 at transcription starting sites (TSS). Down-regulation of TET2 reduces the amount of H2B S112 GlcNAc marks in vivo, which are associated with gene transcription regulation. Taken together, these results reveal a TET2-dependent O-GlcNAcylation of chromatin. The double epigenetic modifications on both DNA and histones by TET2 and OGT coordinate together for the gene transcription regulation.

Summary Ubiquitin-like proteins have been shown to be covalently conjugated to targets. However, the functions of these ubiquitin-like proteins are largely unknown. Here, we have screened most known ubiquitin-like proteins after DNA damage and found that NEDD8 is involved in the DNA damage response. Following various DNA damage stimuli, NEDD8 accumulated at DNA damage sites, and this accumulation was dependent on an E2 enzyme UBE2M and an E3 ubiquitin ligase RNF111. We further found that histone H4 was polyneddylated in response to DNA damage, and NEDD8 was conjugated to the N-terminal lysine residues of H4. Interestingly, the DNA damage-induced polyneddylation chain could be recognized by the MIU (Motif Interacting with Ubiquitin) domain of RNF168. Loss of DNA damage-induced neddylation negatively regulated DNA damage-induced foci formation of RNF168 and its downstream functional partners, such as 53BP1 and BRCA1, thus affecting the normal DNA damage repair process.

A nanocrystal heterojunction LaVO4TiO2 visible light photocatalyst has been successfully prepared by a simple coupled method. The catalyst was characterized by powder X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectra, photoluminescence, and electrochemistry technology.The results showed that the prepared nanocomposite catalysts exhibited strong photocatalytic activity for decomposition of benzene under visible light irradiation with high photochemical stability. The enhanced photocatalytic performance of LaVO4/TiO2 may be attributed to not only the matched band potentials but also interconnected heterojunction of LaVO4 and TiO2 nanoparticles.

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Protein ubiquitination is a critical component of the DNA damage response. To study the mechanism of the DNA damage-induced ubiquitination pathway, we analyzed the impact of the loss of two E3 ubiquitin ligases, RNF8 and Chfr. Interestingly, DNA damage-induced ATM activation is suppressed in RNF8 and Chfr double-deficient (DKO) cells, and DKO mice develop thymic lymphomas that are nearly diploid but harbor clonal chromosome translocations. Moreover, DKO mice and cells are hypersensitive to ionizing radiation. We show evidence that RNF8 and Chfr synergistically regulate histone ubiquitination to control histone H4K16 acetylation through MRG15-dependent acetyltransferase complexes. Through these complexes, RNF8 and CHFR affect chromatin relaxation and modulate ATM activation and DNA damage response pathways. Collectively, our findings demonstrate that two chromatin remodeling factors, RNF8 and Chfr, function together to activate ATM and maintain genomic stability in vivo.

The nanocrystal In 2 S 3 (nc-In 2 S 3 ) has been used as a visible light active photocatalyst. The optical absorption indicated a narrow band gap (E g )1.9 eV) for nc-In 2 S 3 . Compared with TiO 2-x N x , the decomposition of methyl orange using nc-In 2 S 3 revealed enormously enhanced visible light activity. The • OH during the photocatalytic degradation process was detected by terephthalic acid photoluminescence probing technique (TA-PL). The organic intermediate products were successfully separated by liquid chromatogram and subsequently identified by an electrospray ionization (ESI) mass spectral technique. The possible photocatalytic mechanism is presented.

Abstract. The uptake of water by contrails in icesupersaturated air and the release of water after ice particle advection and sedimentation dehydrates the atmosphere at flight levels and redistributes humidity mainly to lower levels. The dehydration is investigated by coupling a plumescale contrail model with a global aerosol-climate model. The contrail model simulates all the individual contrails forming from global air traffic for meteorological conditions as defined by the climate model. The computed contrail cirrus properties compare reasonably with theoretical concepts and observations. The mass of water in aged contrails may exceed 10 6 times the mass of water emitted from aircraft. Many of the ice particles sediment and release water in the troposphere, on average 700 m below the mean flight levels. Simulations with and without coupling are compared. The drying at contrail levels causes thinner and longer-lived contrails with about 15 % reduced contrail radiative forcing (RF). The reduced RF from contrails is on the order of 0.06 W m −2 , slightly larger than estimated earlier because of higher soot emissions. For normal traffic, the RF from dehydration is small compared to interannual variability. A case with emissions increased by 100 times is used to overcome statistical uncertainty. The contrails impact the entire hydrological cycle in the atmosphere by reducing the total water column and the cover by high-and low-level clouds. For normal traffic, the dehydration changes contrail RF by positive shortwave and negative longwave contributions on the order of 0.04 W m −2 , with a small negative net RF. The total net RF from contrails and dehydration remains within the range of previous estimates.

Oligonucleotide/oligosaccharide-binding (OB) fold is a ssDNA or RNA binding motif in prokaryotes and eukaryotes. Unexpectedly, we found that the OB fold of human ssDNA-binding protein 1 (hSSB1) is a poly(ADP ribose) (PAR) binding domain. hSSB1 exhibits highaffinity binding to PAR and recognizes iso-ADP ribose (ADPR), the linkage between two ADPR units. This interaction between PAR and hSSB1 mediates the early recruitment of hSSB1 to the sites of DNA damage. Mutations in the OB fold of hSSB1 that disrupt PAR binding abolish the relocation of hSSB1 to the sites of DNA damage. Moreover, PAR-mediated recruitment of hSSB1 is important for early DNA damage repair. We have screened other OB folds and found that several other OB folds also recognize PAR. Taken together, our study reveals a PAR-binding domain that mediates DNA damage repair.G enomic integrity is constantly challenged by various types of DNA damage, which are induced by DNA replication errors, environmental hazards, and other genotoxic stress. In response to this stress, cells activate an evolutionarily conserved pathway termed the DNA damage response (DDR), to orchestrate various cellular responses for maintaining genomic stability (1-3). It has been shown that poly(ADP ribosyl)ation plays an important role in DDR (4-6). Upon DNA damage induction, poly(ADP ribose) (PAR) polymerases (PARPs), such as PARP1, the founding member of the PARP family, rapidly detect DNA breaks, including single-strand breaks (SSBs) and double-strand breaks (DSBs), and activate PAR synthesis at or adjacent to DNA lesions (7,8). Recent evidence suggests that DNA damage-induced PAR may serve as a docking signal to recruit DDR factors to DNA lesions (7-14). For example, our recent study showed that the BRCT domains of BARD1 and NBS1 recognize PAR, which facilitates the rapid recruitment of the BRCA1/BARD1 complex and NBS1 to the site of DNA damage (15, 16). These results indicate that other DDR factors may also be recruited to DNA damage sites by PAR. Thus, it is important to identify other "readers" of PAR to elucidate the molecular mechanism of PAR in DDR.Previous studies have shown that human ssDNA-binding protein 1 (hSSB1) plays a key role in . hSSB1 is a 211-residue polypeptide containing an oligonucleotide/oligosaccharide-binding (OB) fold at the N terminus. Following DNA damage, hSSB1 quickly relocates to DNA damage sites and regulates foci formation of other DNA damage repair proteins, such as BRCA1 and RAD51 (17,(21)(22)(23)(24). Thus, depletion of hSSB1 impairs the repair of DSBs. In response to DNA damage, hSSB1 is phosphorylated by ATM and regulates ATM-dependent cell cycle checkpoint activation (17,(21)(22)(23)(24). By protein affinity purifications, hSSB1 was shown to tightly associate with other proteins, such as INTS3, forming a multisubunit complex (21-24). INTS3 is a well-folded protein and previously identified as a member in the INTS complex that regulates RNA processing and gene transcription (25). Like hSSB1, INTS3 is also quickly relocated to DNA lesions in r...