Publications by authors named "Esin Isik"

Replication forks stalled at co-transcriptional R-loops can be restarted by a mechanism involving fork cleavage-religation cycles mediated by MUS81 endonuclease and DNA ligase IV (LIG4), which presumably relieve the topological barrier generated by the transcription-replication conflict (TRC) and facilitate ELL-dependent reactivation of transcription. Here, we report that the restart of R-loop-stalled replication forks via the MUS81-LIG4-ELL pathway requires senataxin (SETX), a helicase that can unwind RNA:DNA hybrids. We found that SETX promotes replication fork progression by preventing R-loop accumulation during S-phase.

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Transcription-replication conflicts (TRCs) induce formation of cotranscriptional RNA:DNA hybrids (R-loops) stabilized by G-quadruplexes (G4s) on the displaced DNA strand, which can cause fork stalling. Although it is known that these stalled forks can resume DNA synthesis in a process initiated by MUS81 endonuclease, how TRC-associated G4/R-loops are removed to allow fork passage remains unclear. Here, we identify the mismatch repair protein MutSβ, an MLH1-PMS1 heterodimer termed MutLβ, and the G4-resolving helicase FANCJ as factors that are required for MUS81-initiated restart of DNA replication at TRC sites in human cells.

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Stroke is one of the leading causes of adult disability affecting millions of people worldwide. Post-stroke cognitive and motor impairments diminish quality of life and functional independence. There is an increased risk of having a second stroke and developing secondary conditions with long-term social and economic impacts.

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Fluorine MRI is finding wider acceptance in theranostics applications where imaging of F hotspots of fluorinated contrast material is central. The essence of such applications is to capture ghosting-artifact-free images of the inherently low MR response under clinically viable conditions. To serve this purpose, this work introduces the balanced spiral spectroscopic imaging (BaSSI) sequence, which is implemented on a 3.

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Article Synopsis
  • The LINE-1 retrotransposon is a significant genetic element in humans, contributing to about a third of our genome via a 'copy and paste' method driven by its enzyme, ORF2p, which is linked to diseases like cancer and autoimmunity.
  • Recent studies using X-ray crystallography and cryo-electron microscopy have revealed new structural details of ORF2p, including previously unknown domains and a dynamic conformation that changes during the retrotransposition process.
  • The findings enhance our understanding of L1 replication and its effects on immune responses, creating potential pathways for drug development targeting L1 and related cellular processes.
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Arsenic is a toxic metalloid that affects human health by causing numerous diseases and by being used in the treatment of acute promyelocytic leukemia. Saccharomyces cerevisiae (budding yeast) has been extensively utilized to elucidate the molecular mechanisms underlying arsenic toxicity and resistance in eukaryotes. In this study, we applied a genomic DNA overexpression strategy to identify yeast genes that provide arsenic resistance in wild-type and arsenic-sensitive S.

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Background And Objective: Dementia refers to the loss of memory and other cognitive abilities. Alzheimer's disease (AD), which patients eventually die from, is the most common cause of dementia. In USA, %60 to %80 of dementia cases, are caused by AD.

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Up to 15% of human cancers maintain their telomeres through a telomerase-independent mechanism, termed "alternative lengthening of telomeres" (ALT) that relies on homologous recombination between telomeric sequences. Emerging evidence suggests that the recombinogenic nature of ALT telomeres results from the formation of RNA:DNA hybrids (R-loops) between telomeric DNA and the long-noncoding telomeric repeat-containing RNA (TERRA). Here, we show that the mismatch repair protein MutSβ, a heterodimer of MSH2 and MSH3 subunits, is enriched at telomeres in ALT cancer cells, where it prevents the accumulation of telomeric G-quadruplex (G4) structures and R-loops.

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Tissue-mimicking materials (TMMs) play a key role in the quality assurance of ultrasound diagnostic equipment and should have acoustic properties similar to human tissues. We propose a method to quantify the acoustic properties of TMM samples through the use of an 80 MHz Scanning Acoustic Microscopy (SAM), which provides micrometer resolution and fast data recording. We produced breast TMM samples in varying compositions that resulted in acoustic impedance values in the range of 1.

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Formation of co-transcriptional R-loops underlies replication fork stalling upon head-on transcription-replication encounters. Here, we demonstrate that RAD51-dependent replication fork reversal induced by R-loops is followed by the restart of semiconservative DNA replication mediated by RECQ1 and RECQ5 helicases, MUS81/EME1 endonuclease, RAD52 strand-annealing factor, the DNA ligase IV (LIG4)/XRCC4 complex, and the non-catalytic subunit of DNA polymerase δ, POLD3. RECQ5 disrupts RAD51 filaments assembled on stalled forks after RECQ1-mediated reverse branch migration, preventing a new round of fork reversal and facilitating fork cleavage by MUS81/EME1.

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There are only a few antifungal drugs used systemically in treatment, and invasive fungal infections that are resistant to these drugs are an emerging problem in health care. In this study, we performed a high-copy-number genomic DNA (gDNA) library screening to find and characterize genes that reduce susceptibility to amphotericin B, caspofungin, and voriconazole in We identified the and genes for amphotericin B, and genes for caspofungin, and the and genes for voriconazole. The deletion mutants for and were drug susceptible, but the other mutants had no apparent susceptibility.

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Purpose: In this study we aimed to report a comparative analysis between open and robotic nephron sparing surgeries (NSS) from a single institutional database.

Methods: Patients who have undergone NSS during the robotic era of our institution were included in this study. Open (n = 74) and robotic (n = 59) groups were compared regarding trifecta outcome.

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