Medical Expenditures Associated With Diabetes Among Privately Insured U.S. Youth in 2007

We demonstrate the utilization of the optical Fourier transform technique for serial-toparallel conversion of 64x10-GBd OTDM data tributaries with complex modulation formats into 50-GHz DWDM grid without loss of phase and amplitude information.</p

640 Gb/s timing tolerant demultiplexing using a cascaded long-period fiber grating pulse shaper

An SMF inscribed with two polarization independent long-period gratings is used for sub-picosecond pulse shaping and validated in a 640 Gb/s data demultiplexing experiment, providing a jitter tolerance of 510 fs.</p

RNase H1 directs origin-specific initiation of DNA replication in human mitochondria.

Human mitochondrial DNA (mtDNA) replication is first initiated at the origin of H-strand replication. The initiation depends on RNA primers generated by transcription from an upstream promoter (LSP). Here we reconstitute this process in vitro using purified transcription and replication factors. The majority of all transcription events from LSP are prematurely terminated after ~120 nucleotides, forming stable R-loops. These nascent R-loops cannot directly prime mtDNA synthesis, but must first be processed by RNase H1 to generate 3'-ends that can be used by DNA polymerase γ to initiate DNA synthesis. Our findings are consistent with recent studies of a knockout mouse model, which demonstrated that RNase H1 is required for R-loop processing and mtDNA maintenance in vivo. Both R-loop formation and DNA replication initiation are stimulated by the mitochondrial single-stranded DNA binding protein. In an RNase H1 deficient patient cell line, the precise initiation of mtDNA replication is lost and DNA synthesis is initiated from multiple sites throughout the mitochondrial control region. In combination with previously published in vivo data, the findings presented here suggest a model, in which R-loop processing by RNase H1 directs origin-specific initiation of DNA replication in human mitochondria.This work was supported by Swedish Research Council (www.vr.se) to ARC (2014-6466), MF (2013-3621), and CMG (2017-01257); the Swedish Foundation for Strategic Research (ICA14-0060 to ARC), Swedish Cancer Foundation (www.cancerfonden.se) to MF (CAN 2016/816) and CMG (CAN 2017/631); European Research Council consolidator grant (erc.europa.eu) to MF (DELMIT); the IngaBritt and Arne Lundberg Foundation (www.lundbergsstiftelsen.se) to MF; the Knut and Alice Wallenberg Foundation (kaw.wallenberg.org) to MF and CMG; grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement to CMG (ALFGBG-728151); Core Grant from the Medical Research Council (www.mrc.ac.uk) to MZ; European Research Council advanced grant FP7-322424 (erc.europa.eu) to MZ; and NRJ-Institut de France Grant (foundation.nrj.fr) to MZ

Strand specificity of ribonucleotide excision repair in Escherichia coli

In Escherichia coli, replication of both strands of genomic DNA is carried out by a single replicase—DNA polymerase III holoenzyme (pol III HE). However, in certain genetic backgrounds, the low-fidelity TLS polymerase, DNA polymerase V (pol V) gains access to undamaged genomic DNA where it promotes elevated levels of spontaneous mutagenesis preferentially on the lagging strand. We employed active site mutants of pol III (pol IIIα_S759N) and pol V (pol V_Y11A) to analyze ribonucleotide incorporation and removal from the E. coli chromosome on a genome-wide scale under conditions of normal replication, as well as SOS induction. Using a variety of methods tuned to the specific properties of these polymerases (analysis of lacI mutational spectra, lacZ reversion assay, HydEn-seq, alkaline gel electrophoresis), we present evidence that repair of ribonucleotides from both DNA strands in E. coli is unequal. While RNase HII plays a primary role in leading-strand Ribonucleotide Excision Repair (RER), the lagging strand is subject to other repair systems (RNase HI and under conditions of SOS activation also Nucleotide Excision Repair). Importantly, we suggest that RNase HI activity can also influence the repair of single ribonucleotides incorporated by the replicase pol III HE into the lagging strand

Tracking replication enzymology in vivo by genome-wide mapping of ribonucleotide incorporation

Ribonucleotides are frequently incorporated into DNA during eukaryotic replication. Here we map the genome-wide distribution of these ribonucleotides as markers of replication enzymology in budding yeast, using a new 5′-DNA end-mapping method, Hydrolytic End Sequencing. HydEn-Seq of DNA from ribonucleotide excision repair-deficient strains reveals replicase- and strand-specific patterns of ribonucleotides in the nuclear genome. These patterns support the role of DNA polymerases α and δ in lagging strand replication and of DNA polymerase ε in leading strand replication. They identify replication origins, termination zones and variations in ribonucleotide incorporation frequency across the genome that exceed three orders of magnitude. HydEn-Seq also reveals strand-specific 5′-DNA ends at mitochondrial replication origins, suggesting unidirectional replication of a circular genome. Given the conservation of enzymes that incorporate and process ribonucleotides in DNA, HydEn-Seq can be used to track replication enzymology in other organisms

DNA polymerase η contributes to genome-wide lagging strand synthesis

DNA polymerase η (pol η) is best known for its ability to bypass UV-induced thymine-thymine (T-T) dimers and other bulky DNA lesions, but pol η\ua0also has other cellular roles. Here, we present evidence that pol η competes with DNA polymerases α and δ\ua0for the synthesis of the lagging strand genome-wide, where it also shows a preference for T-T in the DNA template. Moreover, we found that the C-terminus of pol η,\ua0which contains a PCNA-Interacting Protein motif is required for pol η\ua0to function in lagging strand synthesis. Finally, we provide evidence that a pol η dependent signature is also found to be lagging strand specific in patients with skin cancer. Taken together, these findings provide insight into the physiological role of DNA synthesis by pol η and have implications for our understanding of how our genome is replicated to avoid mutagenesis, genome instability and cancer