Mutation in Eftud2 causes craniofacial defects in mice via mis-splicing of Mdm2 and increased P53.

EFTUD2 is mutated in patients with mandibulofacial dysostosis with microcephaly (MFDM). We generated a mutant mouse line with conditional mutation in Eftud2 and used Wnt1-Cre2 to delete it in neural crest cells. Homozygous deletion of Eftud2 causes brain and craniofacial malformations, affecting the same precursors as in MFDM patients.

Cdc48 regulates intranuclear quality control sequestration of the Hsh155 splicing factor in budding yeast.

Cdc48 (known as VCP in mammals) is a highly conserved ATPase chaperone that plays an essential role in the assembly and disassembly of protein-DNA complexes and in degradation of misfolded proteins. We find that in budding yeast, Cdc48 accumulates during cellular stress at intranuclear protein quality control sites (INQ). We show that Cdc48 function is required to suppress INQ formation under non-stress conditions and to promote recovery following genotoxic stress.

Splicing, genome stability and disease: splice like your genome depends on it!

The spliceosome has been implicated in genome maintenance for decades. Recently, a surge in discoveries in cancer has suggested that the oncogenic mechanism of spliceosomal defects may involve defective genome stability. The action of the core spliceosome prevents R-loop accumulation, and regulates the expression of genome stability factors.

Selective defects in gene expression control genome instability in yeast splicing mutants.

RNA processing mutants have been broadly implicated in genome stability, but mechanistic links are often unclear. Two predominant models have emerged: one involving changes in gene expression that perturb other genome maintenance factors and another in which genotoxic DNA:RNA hybrids, called R-loops, impair DNA replication. Here we characterize genome instability phenotypes in yeast splicing factor mutants and find that mitotic defects, and in some cases R-loop accumulation, are causes of genome instability.

RECQ-like helicases Sgs1 and BLM regulate R-loop-associated genome instability.

Sgs1, the orthologue of human Bloom's syndrome helicase BLM, is a yeast DNA helicase functioning in DNA replication and repair. We show that loss increases R-loop accumulation and sensitizes cells to transcription-replication collisions. Yeast lacking accumulate R-loops and γ-H2A at sites of Sgs1 binding, replication pausing regions, and long genes.

Genome-wide bisulfite sensitivity profiling of yeast suggests bisulfite inhibits transcription.

Bisulfite, in the form of sodium bisulfite or metabisulfite, is used commercially as a food preservative. Bisulfite is used in the laboratory as a single-stranded DNA mutagen in epigenomic analyses of DNA methylation. Recently it has also been used on whole yeast cells to induce mutations in exposed single-stranded regions in vivo.

Dermatofibrosarcoma Protuberans: A comprehensive review on the spectrum of clinico-radiological presentations.

Dermatofibrosarcoma Protuberans (DFSP) is a rare malignant soft-tissue neoplasm which is often misdiagnosed due to its indolent clinical course and non-specific radiological appearances. An observation case series was conducted with retrospective review of clinical and radiological data of DFSP patients presenting to a major tertiary hospital in Hong Kong for radiological assessment between November 2006 and February 2016. Seven patients with confirmed histological diagnosis of DFSP were included.

Genome-Wide Mutational Signature of the Chemotherapeutic Agent Mitomycin C in Caenorhabditis elegans.

Cancer therapy largely depends on chemotherapeutic agents that generate DNA lesions. However, our understanding of the nature of the resulting lesions as well as the mutational profiles of these chemotherapeutic agents is limited. Among these lesions, DNA interstrand crosslinks are among the more toxic types of DNA damage.

Dissecting genetic and environmental mutation signatures with model organisms.

Deep sequencing has impacted on cancer research by enabling routine sequencing of genomes and exomes to identify genetic changes associated with carcinogenesis. Researchers can now use the frequency, type, and context of all mutations in tumor genomes to extract mutation signatures that reflect the driving mutational processes. Identifying mutation signatures, however, may not immediately suggest a mechanism.

Multicomponent synthesis of 1-aryl 1,2,4-triazoles.

A multicomponent (single reactor) process for the synthesis of 1-aryl 1,2,4-triazoles was explored and developed. This transformation prepared the 1,2,4-triazole directly from anilines, amino pyridines, and pyrimidines. The reaction scope was explored with 21 different substrates, and the position of the nitrogen atoms in the newly formed ring was established by (15)N labeling and NMR spectroscopy.

Total synthesis and evaluation of vinblastine analogues containing systematic deep-seated modifications in the vindoline subunit ring system: core redesign.

The total synthesis of a systematic series of vinblastine analogues that contain deep-seated structural modifications to the core ring system of the lower vindoline subunit is described. Complementary to the vindoline 6,5 DE ring system, compounds with 5,5, 6,6, and the reversed 5,6 membered DE ring systems were prepared. Both the natural cis and unnatural trans 6,6-membered ring systems proved accessible, with the latter representing a surprisingly effective class for analogue design.

Catharanthine C16 substituent effects on the biomimetic coupling with vindoline: preparation and evaluation of a key series of vinblastine analogues.

The examination of the catharanthine C16 substituent effects on the Fe(III)-promoted biomimetic coupling reaction with vindoline is detailed, confirming the importance of the presence of a C16 electron-withdrawing substituent, and establishing an unanticipated unique role (>10-fold) that the C16 methyl ester plays in the expression of the natural product properties. Thus, replacement of the vinblastine C16' methyl ester with an ethyl ester (10-fold), a cyano group (100-fold), an aldehyde (100-fold), a hydroxymethyl group (1000-fold) or a primary carboxamide (>1000-fold) led to surprisingly large reductions in cytotoxic activity.

Protein engineering with the traceless Staudinger ligation.

The engineering of proteins can illuminate their biological function and improve their performance in a variety of applications. Within the past decade, methods have been developed that facilitate the ability of chemists to manipulate proteins in a controlled manner. Here, we present the traceless Staudinger ligation as a strategy for the convergent chemical synthesis of proteins.

Total synthesis of vinblastine, vincristine, related natural products, and key structural analogues.

Full details of the development of a direct coupling of catharanthine with vindoline to provide vinblastine are described along with key mechanistic and labeling studies. Following an Fe(III)-promoted coupling reaction initiated by generation of a presumed catharanthine radical cation that undergoes a subsequent oxidative fragmentation and diastereoselective coupling with vindoline, addition of the resulting reaction mixture to an Fe(III)-NaBH(4)/air solution leads to oxidation of the C15'-C20' double bond and reduction of the intermediate iminium ion directly providing vinblastine (40-43%) and leurosidine (20-23%), its naturally occurring C20' alcohol isomer. The yield of coupled products, which exclusively possess the natural C16' stereochemistry, approaches or exceeds 80% and the combined yield of the isomeric C20' alcohols is >60%.

Bilateral cervical spondylolysis in a young Chinese woman presenting with a neck injury.

Cervical spondylolysis is an uncommon entity. It is important to recognise its characteristic radiological features and differentiate it from acute cervical fractures or dislocations in patients with neck injuries. We report the relevant clinical and radiological findings seen in a young Chinese woman managed in our hospital after a neck injury who was ultimately diagnosed with bilateral cervical spondylolysis with spondylolisthesis at C6.

Electronic and steric effects on the rate of the traceless Staudinger ligation.

Interplay between electronic effects imparted by phosphinothiol substituents and steric effects imposed by amino-acid reactants affects the rate of the traceless Staudinger ligation of peptides in a predictable manner.

Coulombic effects on the traceless Staudinger ligation in water.

The traceless Staudinger ligation can be mediated by phosphinothiols under physiological conditions. Proximal positive charges are necessary to achieve that transformation, presumably because those charges discourage protonation of the key iminophosphorane intermediate. Here, a series of cationic phosphinothiols is used to probe Coulombic effects on the traceless Staudinger ligation in aqueous buffers.

Protein prosthesis: 1,5-disubstituted[1,2,3]triazoles as cis-peptide bond surrogates.

Proline is unique among the natural amino acids in the similar propensity of its peptide bond to be in the cis or trans conformation. This attribute affects many processes, including the rate at which proteins fold, their structures, and their activities. Other aliphatic amino acids can serve as mimics for proline residues with trans peptide bonds.

Water-soluble phosphinothiols for traceless staudinger ligation and integration with expressed protein ligation.

The traceless Staudinger ligation is an effective means to synthesize an amide bond between two groups of otherwise orthogonal reactivity: a phosphinothioester and an azide. An important application of the Staudinger ligation is in the ligation of peptides at a variety of residues. Here, we demonstrate that the traceless Staudinger ligation can be achieved in water with a water-soluble reagent.

Staudinger ligation of peptides at non-glycyl residues.

The Staudinger ligation provides a means to form an amide bond between a phosphinothioester and azide. This reaction holds promise for the ligation of peptides en route to the total chemical synthesis of proteins. (Diphenylphosphino)methanethiol is the most efficacious of known reagents for mediating the Staudinger ligation of peptides, providing high (> 90%) isolated yields for equimolar couplings in which a glycine residue is at the nascent junction.

Synthesis and characterization of a novel class of reducing agents that are highly neuroprotective for retinal ganglion cells.

Retinal ganglion cells (RGCs) undergo apoptosis after axonal injury, in part regulated by an intracellular superoxide anion burst, for which the target(s) are unknown. Shifting the RGC redox state towards reduction and preventing sulfhydryl oxidation is neuroprotective in vitro and in vivo, implying that one or more sulfhydryls on one or more critical proteins may be involved. We synthesized novel borane-protected analogues of the reductant tris(2-carboxyethyl)phosphine (TCEP) with the intent of increasing cell permeability and improving chemical stability, and tested their ability to increase RGC survival in vitro.

Functional copper at the acetyl-CoA synthase active site.

The bifunctional CO dehydrogenase/acetyl-CoA synthase (CODH/ACS) plays a central role in the Wood-Ljungdahl pathway of autotrophic CO(2) fixation. A recent structure of the Moorella thermoacetica enzyme revealed that the ACS active site contains a [4Fe-4S] cluster bridged to a binuclear Cu-Ni site. Here, biochemical and x-ray absorption spectroscopic (XAS) evidence is presented that the copper ion at the M.

Ribosylnicotinamide kinase domain of NadR protein: identification and implications in NAD biosynthesis.

NAD is an indispensable redox cofactor in all organisms. Most of the genes required for NAD biosynthesis in various species are known. Ribosylnicotinamide kinase (RNK) was among the few unknown (missing) genes involved with NAD salvage and recycling pathways.