SMAD4-deficient intestinal tumors recruit CCR1+ myeloid cells that promote invasion

Inactivation of TGF-beta family signaling is implicated in colorectal tumor progression. Using cis-Apc(+/Delta716) Smad4(+/-) mutant mice (referred to as cis-Apc/Smad4), a model of invasive colorectal cancer in which TGF-beta family signaling is blocked, we show here that a new type of immature myeloid cell (iMC) is recruited from the bone marrow to the tumor invasion front. These CD34(+) iMCs express the matrix metalloproteinases MMP9 and MMP2 and the CC-chemokine receptor 1 (CCR1) and migrate toward the CCR1 ligand CCL9. In adenocarcinomas, expression of CCL9 is increased in the tumor epithelium. By deleting Ccr1 in the background of the cis-Apc/Smad4 mutant, we further show that lack of CCR1 prevents accumulation of CD34(+) iMCs at the invasion front and suppresses tumor invasion. These results indicate that loss of transforming growth factor-beta family signaling in tumor epithelium causes accumulation of iMCs that promote tumor invasion.     

Periostin in inflammation and allergy

We found for the first time that IL-4 and IL-13, signature type 2 cytokines, are able to induce periostin expression. We and others have subsequently shown that periostin is highly expressed in chronic inflammatory diseases―asthma, atopic dermatitis, eosinophilc chronic sinusitis/chronic rhinosinusitis with nasal polyp, and allergic conjunctivitis—and that periostin plays important roles in the pathogenesis of these diseases. The epithelial/mesenchymal interaction via periostin is important for the onset of allergic inflammation, in which periostin derived from fibroblasts acts on epithelial cells or fibroblasts, activating their NF-κB. Moreover, the immune cell/non-immune cell interaction via periostin may be also involved. Now the significance of periostin has been expanded into other inflammatory or fibrotic diseases such as scleroderma and pulmonary fibrosis. The cross-talk of periostin with TGF-β or pro-inflammatory cytokines is important for the underlying mechanism of these diseases. Because of its pathogenic importance and broad expression, diagnostics or therapeutic drugs can be potentially developed to target periostin as a means of treating these diseases.     

The medaka draft genome and insights into vertebrate genome evolution

Teleosts comprise more than half of all vertebrate species and have adapted to a variety of marine and freshwater habitats. Their genome evolution and diversification are important subjects for the understanding of vertebrate evolution. Although draft genome sequences of two pufferfishes have been published, analysis of more fish genomes is desirable. Here we report a high-quality draft genome sequence of a small egg-laying freshwater teleost, medaka (Oryzias latipes). Medaka is native to East Asia and an excellent model system for a wide range of biology, including ecotoxicology, carcinogenesis, sex determination and developmental genetics. In the assembled medaka genome (700 megabases), which is less than half of the zebrafish genome, we predicted 20,141 genes, including approximately 2,900 new genes, using 5'-end serial analysis of gene expression tag information. We found single nucleotide polymorphisms (SNPs) at an average rate of 3.42% between the two inbred strains derived from two regional populations; this is the highest SNP rate seen in any vertebrate species. Analyses based on the dense SNP information show a strict genetic separation of 4 million years (Myr) between the two populations, and suggest that differential selective pressures acted on specific gene categories. Four-way comparisons with the human, pufferfish (Tetraodon), zebrafish and medaka genomes revealed that eight major interchromosomal rearrangements took place in a remarkably short period of approximately 50 Myr after the whole-genome duplication event in the teleost ancestor and afterwards, intriguingly, the medaka genome preserved its ancestral karyotype for more than 300 Myr.     

CENP-B preserves genome integrity at replication forks paused by retrotransposon LTR

Centromere-binding protein B (CENP-B) is a widely conserved DNA binding factor associated with heterochromatin and centromeric satellite repeats. In fission yeast, CENP-B homologues have been shown to silence long terminal repeat (LTR) retrotransposons by recruiting histone deacetylases. However, CENP-B factors also have unexplained roles in DNA replication. Here we show that a molecular function of CENP-B is to promote replication-fork progression through the LTR. Mutants have increased genomic instability caused by replication-fork blockage that depends on the DNA binding factor switch-activating protein 1 (Sap1), which is directly recruited by the LTR. The loss of Sap1-dependent barrier activity allows the unhindered progression of the replication fork, but results in rearrangements deleterious to the retrotransposon. We conclude that retrotransposons influence replication polarity through recruitment of Sap1 and transposition near replication-fork blocks, whereas CENP-B counteracts this activity and promotes fork stability. Our results may account for the role of LTR in fragile sites, and for the association of CENP-B with pericentromeric heterochromatin and tandem satellite repeats.     

Testing homogeneity of Japanese CPI forecasters

This paper investigates whether some forecasters consistently outperform others using Japanese CPI forecast data of 42 forecasters over the past 18 quarters. It finds that the accuracy rankings of 0, 1, 2, and 5‐month forecasts are significantly different from those that might be expected when all forecasters had equal forecasting ability. Moreover, their rankings of the relative forecast levels are also significantly different from a random one. Copyright © 2009 John Wiley & Sons, Ltd.     

A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies

Mitochondrial encephalomyopathies are usually divided into three distinct clinical subgroups: (1) mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS); (2) myoclonus epilepsy associated with ragged-red fibres (MERRF); and (3) chronic progressive external ophthalmoplegia (CPEO) including Kearns-Sayre syndrome. Large deletions of human mitochondrial DNA and a transition mutation at the mitochondrial transfer RNALys gene give rise to CPEO including Kearns-Sayre syndrome and MERRF, respectively. Here we report an A-to-G transition mutation at nucleotide pair 3,243 in the dihydrouridine loop of mitochondrial tRNA(Leu)(UUR) that is specific to patients with MELAS. Because this mutation creates an ApaI restriction site, we could perform a simple molecular diagnostic test for the disease. The mutation was present in 26 out of 31 independent MELAS patients and 1 out of 29 CPEO patients, but absent in the 5 MERRF and 50 controls tested. Southern blot analysis confirmed that the mutant DNA always coexists with the wild-type DNA (heteroplasmy).     

Cloning of a cDNA encoding a non-isopeptide-selective subtype of the endothelin receptor

Endothelin-1 was initially identified as a 21-residue potent vasoconstrictor peptide produced by vascular endothelial cells, but was subsequently found to have many effects on both vascular and non-vascular tissues. The discovery of three isopeptides of the endothelin family, ET-1, ET-2 and ET-3, each possessing a diverse set of pharmacological activities of different potency, suggested the existence of several different endothelin receptor subtypes. Endothelins may elicit biological responses by various signal-transduction mechanisms, including the G protein-coupled activation of phospholipase C and the activation of voltage-dependent Ca2+ channels. Thus, different subtypes of the endothelin receptor may use different signal-transduction mechanisms. Here we report the cloning of a complementary DNA encoding one subtype belonging to the superfamily of G protein-coupled receptors. COS-7 cells transfected with the cDNA express specific and high-affinity binding sites for endothelins, responding to binding by the production of inositol phosphates and a transient increase in the concentration of intracellular free Ca2+. The three endothelin isopeptides are roughly equipotent in displacing 125I-labelled ET-1 binding and causing Ca2+ mobilization. A messenger RNA corresponding to the cDNA is detected in many rat tissues including the brain, kidney and lung but not in vascular smooth muscle cells. These results indicate that this cDNA encodes a 'nonselective' subtype of the receptor which is different from the vascular smooth muscle receptor.     

Functional identification of gene cluster for the aniline metabolic pathway mediated by transposable element

A convenient and widely applicable method has been developed to clone aniline metabolic gene cluster in this study. Three positive recombinant plasmids pDA1, pDB2 and pDB11 were cloned from genomic library of aniline degradation strain AD9. The result of aniline dioxygenase （AD） activity and catechol 2,3-oxygenase （C230） activity assay showed that pDA1 and pDB11 contain aniline dioxygenase genes and catechol 2,3-dioxygenase genes, respectively. The sequence analysis of the total 24.7-kb region revealed that this region contains 25 ORFs, of which 17 genes involve metabolism of aniline. In the gene cluster, the first five genes （tadQTA1A2B） and the subsequent gene （tadR1） were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, respectively, while the others （tadD1C1D2C2EFGIJKL） were expected to encode metacleavage pathway enzymes for catechol degradation. The gene cluster was surrounded by two IS1071 sequences.