Herpes simplex virus ICP27 protein directly interacts with the nuclear pore complex through Nup62, inhibiting host nucleocytoplasmic transport pathways

The herpes simplex virus ICP27 protein is important for the expression and nuclear export of viral mRNAs. Although several binding sites have been mapped along the ICP27 sequence for various RNA and protein partners, including the transport receptor TAP of the host cell nuclear transport machinery, several aspects of ICP27 trafficking through the nuclear pore complex remain unclear. We investigated if ICP27 could interact directly with the nuclear pore complex itself, finding that ICP27 directly binds the core nucleoporin Nup62. This is confirmed through co-immunoprecipitation and in vitro binding assays with purified components. Mapping with ICP27 deletion and point mutants further shows that the interaction requires sequences in both the N and C termini of ICP27. Expression of wild type ICP27 protein inhibited both classical, importin α/β-dependent and transportin-dependent nuclear import. In contrast, an ICP27 point mutant that does not interact with Nup62 had no such inhibitory effect. We suggest that ICP27 association with Nup62 provides additional binding sites at the nuclear pore for ICP27 shuttling, thus supporting ICP27-mediated transport. We propose that ICP27 competes with some host cell transport receptors for binding, resulting in inhibition of those host transport pathways.     

Clinical and genetic studies of Japanese homozygotes for the Gaucher disease L444P mutation

In patients originally genotyped as homoallelic for the Gaucher disease (GD) L444P (1448C) mutation, we sought to confirm previously reported phenotypic differences between Caucasians and Japanese, to determine the prevalence and phenotypic impact of recombinant alleles, and to explore the phenotypic influence of genetic background. We therefore analyzed data from longer-term clinical follow-up, more comprehensive genotyping and polymorphism and mitochondrial DNA (mtDNA) testing in all known Japanese L444P homozygotes (n=15). Our studies demonstrated that, of 12 patients in our series originally diagnosed with non-neuronopathic GD, 9 developed neurological signs/symptoms during follow-up (at a mean of 14 years 11 months±11 years 4 months). Of three patients originally diagnosed with acute neuronopathic (type 2) GD, all three were compound heterozygotes for L444P and the complex allele RecNci I. In the entire series, Pvu II and liver erythrocyte pyruvate kinase (PKLR) polymorphism and prevalence of the 9 bp mtDNA deletion were heterogeneous, and these background genetic factors could not predict phenotypic expression. Our data suggest that, in Japanese as in Caucasian patients, the L444P/L444P genotype is highly associated with subacute neuronopathic (type 3) GD, and the presence of a complex allele together with an L444P allele leads to type 2 disease. Our findings also underline the importance of comprehensive genotyping (particularly testing for recombinant alleles), long-term follow-up and careful neurological examination in patients with early-onset GD. Such measures ultimately may improve genotype/phenotype correlations and, with them, genetic counseling and therapeutic decision making. Electronic Publication     

Spermatogenesis in animals as revealed by electron microscopy

Summary The first indication of differentiation of the Jensen's ring has been detected in an early stage of spermiogenesis of Felis catus Linné when the pair of centrioles takes up a position immediately beneath the plasma membrane. The chromatoid bodies appear in the early spermatid cytoplasm through the nuclear pore complex. In a more advanced stage, such bodies have been found in association with the striated columns, the distal centriole or the proximal part of flagellum and the Jensen's ring. As the spermiogenesis proceeds, the bodies have decreased their size and density, and finally disappear in mature spermatozoa. The chromatoid bodies seem, therefore, to share with the centriole the capacity to form the connecting piece. As a consequence of disorganization of triplet microtubules of the centriole, a noticeable material appears in the center of lumen of the centriole to be identifiable as a distinct precursor of the central pair of axonemal complex. Microtubules are first developed as the sheath of principal piece of the sperm flagellum, originating from the plasma membrane surrounding the axonemal complex.     

NB-598: a potent competitive inhibitor of squalene epoxidase

NB-598, (E)N-ethyl-N-(6,6-dimethyl-2-hepten-4-ynyl)-3-[(3,3'-bith iophen-5-yl)methoxy]benzene-methanamine, was found to inhibit human microsomal squalene epoxidase (from Hep G2 cells) in a competitive manner. NB-598 inhibited cholesterol synthesis from [14C]acetate dose dependently in Hep G2 cells and increased the intracellular radioactivity of squalene. A single oral administration of NB-598 inhibited cholesterol synthesis from [14C]acetate in rats. Moreover, multiple oral administration of NB-598 to dogs decreased serum total and low density lipoprotein cholesterol levels and increased serum squalene levels. After termination of treatment, the reduced serum cholesterol and increased squalene levels returned to their control values.     

Gonadotropin-induced luminal formation in the seminiferous tubules and efferent ductules in young frogs: light and electron microscopic study

To clarify the mechanism of fluid secretion in the testes at the time of gonadotropin-induced spermiation, young Rana nigromaculata were used. As a morphological index of fluid secretion, luminal formation of the seminiferous tubules, and efferent ductules were observed. The following changes were seen by the administration of hCG or frog pituitary: first, the luminal formation of the seminiferous tubules was seen; next, tubular expansion became evident, and finally, luminal formation and expansion were observed in the efferent ductules. These changes were preceded by the separation of cell contact among Sertoli cells and of cell contact between Sertoli cells and the cells of efferent ductules only in the center and the swelling of Sertoli cells and cells of efferent ductules. With regard to the flow of fluid at the time of spermiation, the present results indicate the possibility that there is a difference in the ability for fluid secretion between Sertoli cells and the ductule cells.