Detection of uracil within DNA using a sensitive labeling method for in vitro and cellular applications

The role of uracil in genomic DNA has been recently re-evaluated. It is now widely accepted to be a physiologically important DNA element in diverse systems from specific phages to antibody maturation and Drosophila development. Further relevant investigations would largely benefit from a novel reliable and fast method to gain quantitative and qualitative information on uracil levels in DNA both in vitro and in situ, especially since current techniques does not allow in situ cellular detection. Here, starting from a catalytically inactive uracil-DNA glycosylase protein, we have designed several uracil sensor fusion proteins. The designed constructs can be applied as molecular recognition tools that can be detected with conventional antibodies in dot-blot applications and may also serve as in situ uracil-DNA sensors in cellular techniques. Our method is verified on numerous prokaryotic and eukaryotic cellular systems. The method is easy to use and can be applied in a high-throughput manner. It does not require expensive equipment or complex know-how, facilitating its easy implementation in any basic molecular biology laboratory. Elevated genomic uracil levels from cells of diverse genetic backgrounds and/or treated with different drugs can be demonstrated also in situ, within the cell

CRISPR/Cas9-Mediated Knock-Out of dUTPase in Mice Leads to Early Embryonic Lethality

Sanitization of nucleotide pools is essential for genome maintenance. Deoxyuridine 5′-triphosphate nucleotidohydrolase (dUTPase) is a key enzyme in this pathway since it catalyzes the cleavage of 2′-deoxyuridine 5′-triphosphate (dUTP) into 2′-deoxyuridine 5′-monophosphate (dUMP) and inorganic pyrophosphate. Through its action dUTPase efficiently prevents uracil misincorporation into DNA and at the same time provides dUMP, the substrate for de novo thymidylate biosynthesis. Despite its physiological significance, knock-out models of dUTPase have not yet been investigated in mammals, but only in unicellular organisms, such as bacteria and yeast. Here we generate CRISPR/Cas9-mediated dUTPase knock-out in mice. We find that heterozygous dut +/– animals are viable while having decreased dUTPase levels. Importantly, we show that dUTPase is essential for embryonic development since early dut −/− embryos reach the blastocyst stage, however, they die shortly after implantation. Analysis of pre-implantation embryos indicates perturbed growth of both inner cell mass (ICM) and trophectoderm (TE). We conclude that dUTPase is indispensable for post-implantation development in mice

Nonlinear control of transcription through enhancer-promoter interactions.

Chromosome structure in mammals is thought to regulate transcription by modulating three-dimensional interactions between enhancers and promoters, notably through CTCF-mediated loops and topologically associating domains (TADs)1-4. However, how chromosome interactions are actually translated into transcriptional outputs remains unclear. Here, to address this question, we use an assay to position an enhancer at large numbers of densely spaced chromosomal locations relative to a fixed promoter, and measure promoter output and interactions within a genomic region with minimal regulatory and structural complexity. A quantitative analysis of hundreds of cell lines reveals that the transcriptional effect of an enhancer depends on its contact probabilities with the promoter through a nonlinear relationship. Mathematical modelling suggests that nonlinearity might arise from transient enhancer-promoter interactions being translated into slower promoter bursting dynamics in individual cells, therefore uncoupling the temporal dynamics of interactions from those of transcription. This uncovers a potential mechanism of how distal enhancers act from large genomic distances, and of how topologically associating domain boundaries block distal enhancers. Finally, we show that enhancer strength also determines absolute transcription levels as well as the sensitivity of a promoter to CTCF-mediated transcriptional insulation. Our measurements establish general principles for the context-dependent role of chromosome structure in long-range transcriptional regulation

The genetic legacy of the Hunyadi descendants

The Hunyadi family is one of the most influential families in the history of Central Europe in the 14th–16th centuries. The family’s prestige was established by Johannes Hunyadi, a Turk-beater who rose to the position of governor of the Kingdom of Hungary. His second son, Matthias Hunyadi, became the elected ruler of the Kingdom of Hungary in 1458. The Hunyadi family had unknown origin. Moreover, Matthias failed to found a dynasty because of lacking a legitimate heir and his illegitimate son Johannes Corvinus was unable to obtain the crown. His grandson, Christophorus Corvinus, died in childhood, thus the direct male line of the family ended. In the framework of on interdisciplinary research, we have determined the whole genome sequences of Johannes Corvinus and Christophorus Corvinus by next-generation sequencing technology. Both of them carried the Y-chromosome haplogroup is E1b1b1a1b1a6a1c ~, which is widespread in Eurasia. The father-son relationship was verified using the classical STR method and whole genome data. Christophorus Corvinus belongs to the rare, sporadically occurring T2c1þ146 mitochondrial haplogroup, most frequent around the Mediterranean, while his father belongs to the T2b mitochondrial haplogroup, widespread in Eurasia, both are consistent with the known origin of the mothers. Archaeogenomic analysis indicated that the Corvinus had an ancient European genome composition. Based on the reported genetic data, it will be possible to identify all the other Hunyadi family member, whose only known grave site is known, but who are resting assorted with several other skeletons

Structural model of human dUTPase in complex with a novel proteinaceous inhibitor

Human deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase), essential for DNA integrity, acts as a survival factor for tumor cells and is a target for cancer chemotherapy. Here we report that the Staphylococcal repressor protein StlSaPIBov1 (Stl) forms strong complex with human dUTPase. Functional analysis reveals that this interaction results in significant reduction of both dUTPase enzymatic activity and DNA binding capability of Stl. We conducted structural studies to understand the mechanism of this mutual inhibition. Small-angle X-ray scattering (SAXS) complemented with hydrogen-deuterium exchange mass spectrometry (HDX-MS) data allowed us to obtain 3D structural models comprising a trimeric dUTPase complexed with separate Stl monomers. These models thus reveal that upon dUTPase-Stl complex formation the functional homodimer of Stl repressor dissociates, which abolishes the DNA binding ability of the protein. Active site forming dUTPase segments were directly identified to be involved in the dUTPase-Stl interaction by HDX-MS, explaining the loss of dUTPase activity upon complexation. Our results provide key novel structural insights that pave the way for further applications of the first potent proteinaceous inhibitor of human dUTPase

Középkori magyar uralkodók archeogenetikai vizsgálata

Középkori uralkodóink sírjai a történelem viharaiban elvesztek, maradványaik ismeretlen helyen, azonosítatlanul nyugszanak. Máig egyedül III. Béla maradványai kerültek elő, valamint szent királyaink ereklyéi maradtak meg az utókornak, melyek eredetiségét azonban sokan kétségbe vonják. Munkánk során a legtöbb királyunk temetkezési helyéül szolgált székesfehérvári királyi bazilika területén feltárt maradványok archeogenetikai vizsgálatát végezzük el, és azonosítjuk uralkodóink csontvázait. Emellett a Szent László-herma koponyaereklyéjét is megvizsgáltuk, hogy valódiságát igazoljuk. Míg a székesfehérvári vizsgálatokból csak részeredményeket közlünk, lévén a munka még nem fejeződött be, addig a Herma vizsgálata lezajlott, bemutatjuk, hogy eredetisége igazolást nyert, valóban Szent László koponyáját rejti. Mi több, azt is ismertetjük, hogyan járult hozzá Szent László genomvizsgálata az Árpád-házi maradványok személyazonosításához, és kimutatjuk a honfoglalók genetikai örökségét a Szent Király örökítőanyagában