Assembly defects of human tRNA splicing endonuclease contribute to impaired pre-tRNA processing in pontocerebellar hypoplasia.

Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1.

If Veganism Is Not a Choice: The Moral Psychology of Possibilities in Animal Ethics.

In their daily practices, many ethical vegans choose what to eat, wear, and buy among a range that is limited to the exclusion of animal products. Rather than considering and then rejecting the idea of using such products, doing so often does not occur to them as a possibility at all. In other cases, when confronted with the possibility of consuming animal products, vegans have claimed to reject it by saying that it would be impossible for them to do so.

Budding yeast ATM/ATR control meiotic double-strand break (DSB) levels by down-regulating Rec114, an essential component of the DSB-machinery.

An essential feature of meiosis is Spo11 catalysis of programmed DNA double strand breaks (DSBs). Evidence suggests that the number of DSBs generated per meiosis is genetically determined and that this ability to maintain a pre-determined DSB level, or "DSB homeostasis", might be a property of the meiotic program. Here, we present direct evidence that Rec114, an evolutionarily conserved essential component of the meiotic DSB-machinery, interacts with DSB hotspot DNA, and that Tel1 and Mec1, the budding yeast ATM and ATR, respectively, down-regulate Rec114 upon meiotic DSB formation through phosphorylation.

Spo11-accessory proteins link double-strand break sites to the chromosome axis in early meiotic recombination.

Meiotic recombination between homologous chromosomes initiates via programmed DNA double-strand breaks (DSBs), generated by complexes comprising Spo11 transesterase plus accessory proteins. DSBs arise concomitantly with the development of axial chromosome structures, where the coalescence of axis sites produces linear arrays of chromatin loops. Recombining DNA sequences map to loops, but are ultimately tethered to the underlying axis.

Analysis of protein-DNA interactions during meiosis by quantitative chromatin immunoprecipitation (qChIP).

During meiotic prophase a number of important events require recombination between maternal and paternal chromosomes, which is initiated through the introduction of DNA double-strand breaks (DSBs). The majority of DSBs, which mostly occur at so-called hotspots, have been located between cohesin binding sites. qChIP (chromatin immunoprecipitation quantified by real-time PCR) is a sensitive, accurate, and cost-efficient alternative to ChIP-on-Chip for the analysis of noncovalent protein-DNA interactions at defined binding sites in vivo.

A rare case of penile fracture with complete urethral rupture during sexual intercourse.

Fracture of the penis during intercourse is a relatively uncommon condition. We report a rare case with laceration of bilateral corpora cavernosa and associated complete urethral rupture. The patient underwent immediate surgical repair of the penile fracture with primary urethroplasty.