CXorf6 is a causative gene for hypospadias

46,XY disorders of sex development (DSD) refer to a wide range of abnormal genitalia, including hypospadias, which affects approximately 0.5% of male newborns. We identified three different nonsense mutations of CXorf6 in individuals with hypospadias and found that its mouse homolog was specifically expressed in fetal Sertoli and Leydig cells around the critical period for sex development. These data imply that CXorf6 is a causative gene for hypospadias.     

De novo mutations in the gene encoding STXBP1 (MUNC18-1) cause early infantile epileptic encephalopathy

Early infantile epileptic encephalopathy with suppression-burst (EIEE), also known as Ohtahara syndrome, is one of the most severe and earliest forms of epilepsy. Using array-based comparative genomic hybridization, we found a de novo 2.0-Mb microdeletion at 9q33.3-q34.11 in a girl with EIEE. Mutation analysis of candidate genes mapped to the deletion revealed that four unrelated individuals with EIEE had heterozygous missense mutations in the gene encoding syntaxin binding protein 1 (STXBP1). STXBP1 (also known as MUNC18-1) is an evolutionally conserved neuronal Sec1/Munc-18 (SM) protein that is essential in synaptic vesicle release in several species. Circular dichroism melting experiments revealed that a mutant form of the protein was significantly thermolabile compared to wild type. Furthermore, binding of the mutant protein to syntaxin was impaired. These findings suggest that haploinsufficiency of STXBP1 causes EIEE.     

ITPKC functional polymorphism associated with Kawasaki disease susceptibility and formation of coronary artery aneurysms

Kawasaki disease is a pediatric systemic vasculitis of unknown etiology for which a genetic influence is suspected. We identified a functional SNP (itpkc_3) in the inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) gene on chromosome 19q13.2 that is significantly associated with Kawasaki disease susceptibility and also with an increased risk of coronary artery lesions in both Japanese and US children. Transfection experiments showed that the C allele of itpkc_3 reduces splicing efficiency of the ITPKC mRNA. ITPKC acts as a negative regulator of T-cell activation through the Ca2+/NFAT signaling pathway, and the C allele may contribute to immune hyper-reactivity in Kawasaki disease. This finding provides new insights into the mechanisms of immune activation in Kawasaki disease and emphasizes the importance of activated T cells in the pathogenesis of this vasculitis.     

Antibacterial activity in the egg mass of a sea hare

Summary The eggs of a sea hare,Aplysia kurodai, contained antibacterial factors which probably play a role in the defense of eggs against bacterial infection. The active factors were composed of several heat-labile proteins, unrelated to lysozyme, and were produced in the albumen gland.     

Electrophysiology of mammalian hypothalamic and interpeduncular neurons in vitro.

Electrical activities of the hypothalamic and interpeduncular neurons were studied in vitro in brain slices prepared from the guinea-pig brain stem. Neurons preserved resting membrane potentials comparable to those of neurons in vivo, responded to stimulation of the afferent fibres, and retained stable spontaneous firings for more than several hours.     

Optimal isotope labelling for NMR protein structure determinations

Nuclear-magnetic-resonance spectroscopy can determine the three-dimensional structure of proteins in solution. However, its potential has been limited by the difficulty of interpreting NMR spectra in the presence of broadened and overlapping resonance lines and low signal-to-noise ratios. Here we present stereo-array isotope labelling (SAIL), a technique that can overcome many of these problems by applying a complete stereospecific and regiospecific pattern of stable isotopes that is optimal with regard to the quality and information content of the resulting NMR spectra. SAIL uses exclusively chemically and enzymatically synthesized amino acids for cell-free protein expression. We demonstrate for the 17-kDa protein calmodulin and the 41-kDa maltodextrin-binding protein that SAIL offers sharpened lines, spectral simplification without loss of information, and the ability to rapidly collect the structural restraints required to solve a high-quality solution structure for proteins twice as large as commonly solved by NMR. It thus makes a large class of proteins newly accessible to detailed solution structure determination.     

Crystal structure of squid rhodopsin

Invertebrate phototransduction uses an inositol-1,4,5-trisphosphate signalling cascade in which photoactivated rhodopsin stimulates a G(q)-type G protein, that is, a class of G protein that stimulates membrane-bound phospholipase Cbeta. The same cascade is used by many G-protein-coupled receptors, indicating that invertebrate rhodopsin is a prototypical member. Here we report the crystal structure of squid (Todarodes pacificus) rhodopsin at 2.5 A resolution. Among seven transmembrane alpha-helices, helices V and VI extend into the cytoplasmic medium and, together with two cytoplasmic helices, they form a rigid protrusion from the membrane surface. This peculiar structure, which is not seen in bovine rhodopsin, seems to be crucial for the recognition of G(q)-type G proteins. The retinal Schiff base forms a hydrogen bond to Asn 87 or Tyr 111; it is far from the putative counterion Glu 180. In the crystal, a tight association is formed between the amino-terminal polypeptides of neighbouring monomers; this intermembrane dimerization may be responsible for the organization of hexagonally packed microvillar membranes in the photoreceptor rhabdom.     

Possible explanation for interictal-ictal transition: evolution of epileptiform activity in hippocampal slice by chloride depletion.

In thin hippocampal slices, paroxysmal epileptiform discharge was generated in high potassium medium. Removal of chloride from the high potassium medium caused explosive potentiation of the paroxysmal discharge and emergence of clonic relapsing discharges. Evolution of the paroxysm to regenerative seizure was attributed to the reduction of inhibitory postsynaptic potentials.     

A genome-wide association study identifies three new risk loci for Kawasaki disease

We performed a genome-wide association study (GWAS) of Kawasaki disease in Japanese subjects using data from 428 individuals with Kawasaki disease (cases) and 3,379 controls genotyped at 473,803 SNPs. We validated the association results in two independent replication panels totaling 754 cases and 947 controls. We observed significant associations in the FAM167A-BLK region at 8p22-23 (rs2254546, P = 8.2 × 10(-21)), in the human leukocyte antigen (HLA) region at 6p21.3 (rs2857151, P = 4.6 × 10(-11)) and in the CD40 region at 20q13 (rs4813003, P = 4.8 × 10(-8)). We also replicated the association of a functional SNP of FCGR2A (rs1801274, P = 1.6 × 10(-6)) identified in a recently reported GWAS of Kawasaki disease. Our findings provide new insights into the pathogenesis and pathophysiology of Kawasaki disease.     

Mutations affecting components of the SWI/SNF complex cause Coffin-Siris syndrome

By exome sequencing, we found de novo SMARCB1 mutations in two of five individuals with typical Coffin-Siris syndrome (CSS), a rare autosomal dominant anomaly syndrome. As SMARCB1 encodes a subunit of the SWItch/Sucrose NonFermenting (SWI/SNF) complex, we screened 15 other genes encoding subunits of this complex in 23 individuals with CSS. Twenty affected individuals (87%) each had a germline mutation in one of six SWI/SNF subunit genes, including SMARCB1, SMARCA4, SMARCA2, SMARCE1, ARID1A and ARID1B.