Adiponectin stimulates glucose utilization and fatty-acid oxidation by activating AMP-activated protein kinase

Adiponectin (Ad) is a hormone secreted by adipocytes that regulates energy homeostasis and glucose and lipid metabolism. However, the signaling pathways that mediate the metabolic effects of Ad remain poorly identified. Here we show that phosphorylation and activation of the 5'-AMP-activated protein kinase (AMPK) are stimulated with globular and full-length Ad in skeletal muscle and only with full-length Ad in the liver. In parallel with its activation of AMPK, Ad stimulates phosphorylation of acetyl coenzyme A carboxylase (ACC), fatty-acid oxidation, glucose uptake and lactate production in myocytes, phosphorylation of ACC and reduction of molecules involved in gluconeogenesis in the liver, and reduction of glucose levels in vivo. Blocking AMPK activation by dominant-negative mutant inhibits each of these effects, indicating that stimulation of glucose utilization and fatty-acid oxidation by Ad occurs through activation of AMPK. Our data may provide a novel paradigm that an adipocyte-derived antidiabetic hormone, Ad, activates AMPK, thereby directly regulating glucose metabolism and insulin sensitivity in vitro and in vivo.

Fate of the mammalian cranial neural crest during tooth and mandibular morphogenesis

Neural crest cells are multipotential stem cells that contribute extensively to vertebrate development and give rise to various cell and tissue types. Determination of the fate of mammalian neural crest has been inhibited by the lack of appropriate markers. Here, we make use of a two-component genetic system for indelibly marking the progeny of the cranial neural crest during tooth and mandible development. In the first mouse line, Cre recombinase is expressed under the control of the Wnt1 promoter as a transgene. Significantly, Wnt1 transgene expression is limited to the migrating neural crest cells that are derived from the dorsal CNS. The second mouse line, the ROSA26 conditional reporter (R26R), serves as a substrate for the Cre-mediated recombination. Using this two-component genetic system, we have systematically followed the migration and differentiation of the cranial neural crest (CNC) cells from E9.5 to 6 weeks after birth. Our results demonstrate, for the first time, that CNC cells contribute to the formation of condensed dental mesenchyme, dental papilla, odontoblasts, dentine matrix, pulp, cementum, periodontal ligaments, chondrocytes in Meckel's cartilage, mandible, the articulating disc of temporomandibular joint and branchial arch nerve ganglia. More importantly, there is a dynamic distribution of CNC- and non-CNC-derived cells during tooth and mandibular morphogenesis. These results are a first step towards a comprehensive understanding of neural crest cell migration and differentiation during mammalian craniofacial development. Furthermore, this transgenic model also provides a new tool for cell lineage analysis and genetic manipulation of neural-crest-derived components in normal and abnormal embryogenesis.

TAZ: a novel transcriptional co-activator regulated by interactions with 14-3-3 and PDZ domain proteins

The highly conserved and ubiquitously expressed 14-3-3 proteins regulate differentiation, cell cycle progression and apoptosis by binding intracellular phosphoproteins involved in signal transduction. By screening in vitro translated cDNA pools for the ability to bind 14-3-3, we identified a novel transcriptional co-activator, TAZ (transcriptional co-activator with PDZ-binding motif) as a 14-3-3-binding molecule. TAZ shares homology with Yes-associated protein (YAP), contains a WW domain and functions as a transcriptional co-activator by binding to the PPXY motif present on transcription factors. 14-3-3 binding requires TAZ phosphorylation on a single serine residue, resulting in the inhibition of TAZ transcriptional co-activation through 14-3-3-mediated nuclear export. The C-terminus of TAZ contains a highly conserved PDZ-binding motif that localizes TAZ into discrete nuclear foci and is essential for TAZ-stimulated gene transcription. TAZ uses this same motif to bind the PDZ domain-containing protein NHERF-2, a molecule that tethers plasma membrane ion channels and receptors to cytoskeletal actin. TAZ may link events at the plasma membrane and cytoskeleton to nuclear transcription in a manner that can be regulated by 14-3-3.

A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Abeta

Through functional expression screening, we identified a gene, designated Humanin (HN) cDNA, which encodes a short polypeptide and abolishes death of neuronal cells caused by multiple different types of familial Alzheimer's disease genes and by Abeta amyloid, without effect on death by Q79 or superoxide dismutase-1 mutants. Transfected HN cDNA was transcribed to the corresponding polypeptide and then was secreted into the cultured medium. The rescue action clearly depended on the primary structure of HN. This polypeptide would serve as a molecular clue for the development of new therapeutics for Alzheimer's disease targeting neuroprotection.

PEBP2/PEA2 represents a family of transcription factors homologous to the products of the Drosophila runt gene and the human AML1 gene

cDNAs representing the alpha subunit of polyomavirus enhancer binding protein 2 (PEBP2; also called PEA2) were isolated. The products of the cDNAs are highly homologous to that of Drosophila segmentation gene runt (run) for an N-proximal 128-amino acid region showing 66% identity. The run homology region encompasses the domain capable of binding to a specific nucleotide sequence motif and of dimerizing with the companion beta subunit. The human AML1 gene related to t(8;21) acute myeloid leukemia also had a run homology region. Together with the beta subunit, which increases the affinity of the alpha subunit to DNA without binding to DNA by itself, PEBP2 represents a newly discovered family of transcription factor. The major species of PEBP2 alpha mRNA was expressed in T-cell lines but not in B-cell lines tested. Evidence indicated that PEBP2 functions as a transcriptional activator and is involved in regulation of T-cell-specific gene expression.

The transient receptor potential protein homologue TRP6 is the essential component of vascular alpha(1)-adrenoceptor-activated Ca(2+)-permeable cation channel

The Drosophila transient receptor potential protein (TRP) and its mammalian homologues are thought to be Ca(2+)-permeable cation channels activated by G protein (G(q/11))-coupled receptors and are regarded as an interesting molecular model for the Ca(2+) entry mechanisms associated with stimulated phosphoinositide turnover and store depletion. However, there is little unequivocal evidence linking mammalian TRPs with particular native functions. In this study, we have found that heterologous expression of murine TRP6 in HEK293 cells reproduces almost exactly the essential biophysical and pharmacological properties of alpha(1)-adrenoceptor-activated nonselective cation channels (alpha(1)-AR-NSCC) previously identified in rabbit portal vein smooth muscle. Such properties include activation by diacylglycerol; S-shaped current-voltage relationship; high divalent cation permeability; unitary conductance of 25 to 30 pS and augmentation by flufenamate and Ca(2+); and blockade by Cd(2+), La(3+), Gd(3+), SK&F96365, and amiloride. Reverse transcriptase-polymerase chain reaction and confocal laser scanning microscopy using TRP6-specific primers and antisera revealed that the level of TRP6 mRNA expression was remarkably high in both murine and rabbit portal vein smooth muscles as compared with other TRP subtypes, and the immunoreactivity to TRP6 protein was localized near the sarcolemmal region of single rabbit portal vein myocytes. Furthermore, treatment of primary cultured portal vein myocytes with TRP6 antisense oligonucleotides resulted in marked inhibition of TRP6 protein immunoreactivity as well as selective suppression of alpha(1)-adrenoceptor-activated, store depletion-independent cation current and Ba(2+) influx. These results strongly indicate that TRP6 is the essential component of the alpha(1)-AR-NSCC, which may serve as a store depletion-independent Ca(2+) entry pathway during increased sympathetic activity.

A WW domain-containing yes-associated protein (YAP) is a novel transcriptional co-activator

A protein module called the WW domain recognizes and binds to a short oligopeptide called the PY motif, PPxY, to mediate protein-protein interactions. The PY motif is present in the transcription activation domains of a wide range of transcription factors including c-Jun, AP-2, NF-E2, C/EBPalpha and PEBP2/CBF, suggesting that it plays an important role in transcriptional activation. We show here that mutation of the PY motif in the subregion of the activation domain of the DNA-binding subunit of PEBP2, PEBP2alpha, abolishes its transactivation function. Using yeast two-hybrid screening, we demonstrate that Yes-associated protein (YAP) binds to the PY motif of PEBP2alpha through its WW domain. The C-terminal region of YAP fused to the DNA-binding domain of GAL4 showed transactivation as strong as that of GAL4-VP16. Exogenously expressed YAP conferred transcription-stimulating activity on the PY motif fused to the GAL4 DNA-binding domain as well as to native PEBP2alpha. The osteocalcin promoter was stimulated by exogenous PEBP2alphaA and a dominant negative form of YAP strongly inhibited this activity, suggesting YAP involvement in this promoter activity in vivo. These results indicate that the PY motif is a novel transcription activation domain that functions by recruiting YAP as a strong transcription activator to target genes.

Antitumor effect of genetically engineered mesenchymal stem cells in a rat glioma model

The prognosis of patients with malignant glioma is extremely poor, despite the extensive surgical treatment that they receive and recent improvements in adjuvant radio- and chemotherapy. In the present study, we propose the use of gene-modified mesenchymal stem cells (MSCs) as a new tool for gene therapy of malignant brain neoplasms. Primary MSCs isolated from Fischer 344 rats possessed excellent migratory ability and exerted inhibitory effects on the proliferation of 9L glioma cell in vitro. We also confirmed the migratory capacity of MSCs in vivo and showed that when they were inoculated into the contralateral hemisphere, they migrated towards 9L glioma cells through the corpus callosum. MSCs implanted directly into the tumor localized mainly at the border between the 9L tumor cells and normal brain parenchyma, and also infiltrated into the tumor bed. Intratumoral injection of MSCs caused significant inhibition of 9L tumor growth and increased the survival of 9L glioma-bearing rats. Gene-modification of MSCs by infection with an adenoviral vector encoding human interleukin-2 (IL-2) clearly augmented the antitumor effect and further prolonged the survival of tumor-bearing rats. Thus, gene therapy employing MSCs as a targeting vehicle would be promising as a new therapeutic approach for refractory brain tumor.

Expression of connective tissue growth factor in human renal fibrosis

Chronic renal failure may occur in etiologically diverse renal diseases and can be caused by hemodynamic, immunologic and metabolic factors. Initial damage may evoke irreversible scarring, which involves production of a number of proinflammatory and fibrogenic cytokines, including platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF-beta). Connective tissue growth factor (CTGF), a cytokine of the family of growth regulators comprising sef10, cyr61, CTGF and nov, has recently been described in association with scleroderma and other scarring conditions. We investigated CTGF mRNA expression in 65 human renal biopsy specimens of various renal diseases by in situ hybridization. In control human kidney CTFG mRNA was mainly expressed in visceral epithelial cells, parietal epithelial cells, and some interstitial cells. Connective tissue growth factor was strongly up-regulated in the extracapillary and severe mesangial proliferative lesions of crescentic glomerulonephritis, IgA nephropathy, focal and segmental glomerulosclerosis and diabetic nephropathy. An increase in the number of cells expressing CTGF mRNA was observed at sites of chronic tubulointerstitial damage, which correlated with the degree of damage. in the tubulointerstitial area the majority of the CTGF mRNA positive cells coexpressed alpha-smooth muscle actin, and were negative for macrophage markers. Our results indicate that CTGF may be a common growth factor involved in renal fibrosis.

Hypertriglyceridemia as a result of human apo CIII gene expression in transgenic mice

Primary and secondary hypertriglyceridemia is common in the general population, but the biochemical basis for this disease is largely unknown. With the use of transgenic technology, two lines of mice were created that express the human apolipoprotein CIII gene. One of these mouse lines with 100 copies of the gene was found to express large amounts of the protein and to be severely hypertriglyceridemic. The other mouse line with one to two copies of the gene expressed low amounts of the protein, but nevertheless manifested mild hypertriglyceridemia. Thus, overexpression of apolipoprotein CIII can be a primary cause of hypertriglyceridemia in vivo and may provide one possible etiology for this common disorder in humans.

Everolimus plus exemestane for hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: overall survival results from BOLERO-2†

BACKGROUND

The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with hormone-receptor-positive (HR(+)), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.

PATIENTS AND METHODS

BOLERO-2 is a phase III, double-blind, randomized international trial comparing EVE 10 mg/day plus EXE 25 mg/day versus placebo (PBO) + EXE 25 mg/day in postmenopausal women with HR(+) advanced breast cancer with prior exposure to NSAIs. The primary end point was PFS by local investigator assessment; OS was a key secondary end point.

RESULTS

At the time of data cutoff (3 October 2013), 410 deaths had occurred and 13 patients remained on treatment. Median OS in patients receiving EVE + EXE was 31.0 months [95% confidence interval (CI) 28.0-34.6 months] compared with 26.6 months (95% CI 22.6-33.1 months) in patients receiving PBO + EXE (hazard ratio = 0.89; 95% CI 0.73-1.10; log-rank P = 0.14). Poststudy treatments were received by 84% of patients in the EVE + EXE arm versus 90% of patients in the PBO + EXE arm. Types of poststudy therapies were balanced across arms, except for chemotherapy (53% EVE + EXE versus 63% PBO + EXE). No new safety concerns were identified.

CONCLUSIONS

In BOLERO-2, adding EVE to EXE did not confer a statistically significant improvement in the secondary end point OS despite producing a clinically meaningful and statistically significant improvement in the primary end point, PFS (4.6-months prolongation in median PFS; P < 0.0001). Ongoing translational research should further refine the benefit of mTOR inhibition and related pathways in this treatment setting.

TRIAL REGISTRATION NUMBER

NCT00863655.

Surface micropatterning to regulate cell functions

The current technology available for surface microfabrication with macromolecules to regulate cell functions is reviewed. Surface topology, and surface modification with hydrophilic or hydrophobic polymers, electrically charged polymers, stimuli-responsive macromolecules, polysaccharide, and proteins involving adhesion or growth factors are discussed. These surface-microfabricatec biomaterials had the ability to regulate cell functions such as proliferation, differentiation, and apoptosis.

Molecular cloning and characterization of PEBP2 beta, the heterodimeric partner of a novel Drosophila runt-related DNA binding protein PEBP2 alpha

Polyomavirus enhancer binding protein, PEBP2 (PEA2), is a heterodimer of two distinct subunits, alpha and beta, of which the former directly binds to DNA and the latter acts auxiliary to enhance the DNA binding. Recent cloning studies has revealed that the alpha subunit is homologous to the products of the Drosophila segmentation gene runt and the human AML1 gene, and that it functions as a major regulator for the T cell-specific gene expression. We have currently cloned cDNAs for the beta subunit. The isolated cDNAs contain three isoforms that are presumed to arise from alternative RNA splicing and encode polypeptides consisting of 187, 182, and 155 amino acids, respectively. These polypeptides neither show any significant homology with known other proteins including the alpha subunit nor have any known DNA-binding and dimerization domains. Thus, PEBP2, as the complex of these subunits, is thought to constitute an entirely novel category of heteromeric transcriptional regulator together with the Runt and AML1 proteins. Gel retardation assays of the cDNA-encoded proteins produced in an in vitro translation system or in Escherichia coli demonstrated that the larger two beta isoforms, but not the smallest one, can dimerize with the alpha subunit. Furthermore, this heterodimerization was shown to cause a marked increase in the intrinsic DNA binding affinity of the alpha subunit.

Spatial and temporal analysis of human motor activity using noninvasive NIR topography

The effect of motor activity on the left fronto-central region of the human brain was analyzed spatially and temporally by using noninvasive near-infrared light (NIR) topography. The changes in oxygenation states caused by motor activity were measured using intensity-modulated NIR spectroscopy at ten measurement positions on the head surface. The subject randomly performed unilateral finger opposition for 30 s as motor stimulation. When the subject performed contralateral (right) finger movement, significant increases in both oxygenated hemoglobin (oxy-Hb) and total hemoglobin (total-Hb) and decreases in deoxygenated hemoglobin (deoxy-Hb) were observed in a particular area. By mapping the static topograms of the changes of each Hb and comparing them with an anatomical image of MRI, it was found that the particular area was located on the motor cortex along the central sulcus. By mapping the dynamic topograms of the changes of total-Hb, which reflect the cerebral blood volume, and analyzing the spatiotemporal hemodynamic changes associated with the brain activity, it was found that the regional change in cerebral blood volume in the primary motor area overlaps the global change around the motor cortex. These results demonstrate that NIR topography can be used to effectively observe the human brain activity.

A role for hematopoietic stem cells in promoting angiogenesis

Angiogenesis is an important event for embryonic organogenesis as well as for tissue repair in the adult. Here, we show that hematopoietic stem cells (HSCs) play important roles for angiogenesis during embryogenesis. To investigate the role of HSCs in endothelial cell (EC) development, we analyzed AML1-deficient embryos, which lack definitive hematopoiesis. These embryos showed defective angiogenesis in the head and pericardium. Para-aortic splanchnopleural (P-Sp) explant cultures on stromal cells (P-Sp culture) did not generate definitive hematopoietic cells and showed defective angiogenesis in the AML1 null embryo. Disrupted angiogenesis in P-Sp cultures from AML1 null embryos was rescued by addition of HSCs or angiopoietin-1 (Ang1). HSCs, which express Ang1, directly promoted migration of ECs in vivo and in vitro. These results indicate that HSCs are critical for angiogenesis.

Helicobacter pylori CagA protein can be tyrosine phosphorylated in gastric epithelial cells

Attachment of Helicobacter pylori to gastric epithelial cells induces various cellular responses, including the tyrosine phosphorylation of an unknown 145-kD protein and interleukin 8 production. Here we show that this 145-kD protein is the cagA product of H. pylori, an immunodominant, cytotoxin-associated antigen. Epithelial cells infected with various H. pylori clinical isolates resulted in generation of tyrosine-phosphorylated proteins ranging from 130 to 145 kD in size that were also induced in vitro by mixing host cell lysate with bacterial lysate. When epithelial cells were infected with [(35)S]methionine-labeled H. pylori, a radioactive 145-kD protein was detected in the immunoprecipitates with antiphosphotyrosine antibody or anti-CagA (cytotoxin-associated gene A) antibody. Consistently, the 145-kD protein recognized by the anti-CagA and antiphosphotyrosine antibodies was induced in epithelial cells after infection of wild-type H. pylori but not the cagA::Km mutant. Furthermore, the amino acid sequence of the phosphorylated 145-kD protein induced by H. pylori infection was identical to the H. pylori CagA sequence. These results reveal that the tyrosine-phosphorylated 145-kD protein is H. pylori CagA protein, which may be delivered from attached bacteria into the host cytoplasm. The identification of the tyrosine-phosphorylated protein will thus provide further insights into understanding the precise roles of CagA protein in H. pylori pathogenesis.

Cell-free production and stable-isotope labeling of milligram quantities of proteins

We have improved the productivity of an Escherichia coli cell-free protein synthesis system. First, creatine phosphate and creatine kinase were used as the energy source regeneration system, and the other components of the reaction mixture were optimized. Second, the E. coli S30 cell extract was condensed by dialysis against a polyethylene glycol solution to increase the rate of synthesis. Third, during the protein synthesis, the reaction mixture was dialyzed against a low-molecular-weight substrate solution to prolong the reaction. Thus, the yield of chloramphenicol acetyltransferase was raised to 6 mg/ml of reaction mixture. Stable-isotope labeling of a protein with 13C/15N-labeled amino acids for NMR spectroscopy was achieved by this method.

Interaction and functional cooperation of PEBP2/CBF with Smads. Synergistic induction of the immunoglobulin germline Calpha promoter

Smads are signal transducers for members of the transforming growth factor-beta (TGF-beta) superfamily. Upon ligand stimulation, receptor-regulated Smads (R-Smads) are phosphorylated by serine/threonine kinase receptors, form complexes with common-partner Smad, and translocate into the nucleus, where they regulate the transcription of target genes together with other transcription factors. Polyomavirus enhancer binding protein 2/core binding factor (PEBP2/CBF) is a transcription factor complex composed of alpha and beta subunits. The alpha subunits of PEBP2/CBF, which contain the highly conserved Runt domain, play essential roles in hematopoiesis and osteogenesis. Here we show that three mammalian alpha subunits of PEBP2/CBF form complexes with R-Smads that act in TGF-beta/activin pathways as well as those acting in bone morphogenetic protein (BMP) pathways. Among them, PEBP2alphaC/CBFA3/AML2 forms a complex with Smad3 and stimulates transcription of the germline Ig Calpha promoter in a cooperative manner, for which binding of both factors to their specific binding sites is essential. PEBP2 may thus be a nuclear target of TGF-beta/BMP signaling.

Coronary aneurysms in infants and young children with acute febrile mucocutaneous lymph node syndrome

In 1967, Kawasaki, in Japan, first described a new syndrome affecting infants and young children-an acute, febrile illness with mucocutaneous involvement associated with swelling of cervical lymph nodes. The prognosis is usually good but recently it has become evident that 1-2 percent of the patients die suddenly from acute heart failure. Infantile polyarteritis (nodosa-like arteritis) accompained by coronary aneurysm and thrombosis has been noted in postmortem examinations. Twenty patients surviving the illness were examined by coronary angiography; 12 of the 20 had abnormal coronary angiograms; seven patients had coronary aneurysms. Complete regression of the coronary aneurysms was proved in two patients at subsequent angiography. One patient developed mitral regurgitation as a result of papillary muscle dysfunction. One had a coronary aneurysm without symptoms two years after the onset of illness.

Fetal liver development requires a paracrine action of oncostatin M through the gp130 signal transducer

Fetal liver, the major site of hematopoiesis during embryonic development, acquires additional various metabolic functions near birth. Although liver development has been characterized biologically as consisting of several distinct steps, the molecular events accompanying this process are just beginning to be characterized. In this study, we have established a novel culture system of fetal murine hepatocytes and investigated factors required for development of hepatocytes. We found that oncostatin M (OSM), an interleukin-6 family cytokine, in combination with glucocorticoid, induced maturation of hepatocytes as evidenced by morphological changes that closely resemble more differentiated hepatocytes, expression of hepatic differentiation markers and intracellular glycogen accumulation. Consistent with these in vitro observations, livers from mice deficient for gp130, an OSM receptor subunit, display defects in maturation of hepatocytes. Interestingly, OSM is expressed in CD45(+) hematopoietic cells in the developing liver, whereas the OSM receptor is expressed predominantly in hepatocytes. These results suggest a paracrine mechanism of hepatogenesis; blood cells, transiently expanding in the fetal liver, produce OSM to promote development of hepatocytes in vivo.

Activation of mitogen-activated protein kinases/extracellular signal-regulated kinases in human hepatocellular carcinoma

Mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) is a key molecule in intracellular signal transducing pathways that transport extracellular stimuli from cell surface to nuclei. MAPK/ERK has been revealed to be involved in the physiological proliferation of mammalian cells and also to potentiate them to transform. However, its role in the outgrowth of human hepatocellular carcinoma (HCC) has yet to be clarified. Therefore, in this study, we investigated the activation of MAPK/ERK and its associated gene expression in HCC. MAPK/ERK was activated in 15 of 26 cases of HCC we examined (58%), and its activity level was significantly higher in HCC than in the adjacent non-cancerous lesions. Besides, MAPK/ERK activation in HCC was positively correlated with protein expression of transcription factor c-Fos. Furthermore, in 25 of 26 cases of HCC which genomic DNA was available, 22 cases without genomic DNA amplification exhibited positive correlation, not only between protein expression of c-Fos and cyclin D1, but also between MAPK/ERK activation and cyclin D1 expression. Concerning the relationship between MAPK/ERK activation and the clinicohistopathological features of HCC, the tumor (HCC) versus non-tumor (non-cancerous counterpart) ratio (T/N) of MAPK/ERK activity was positively correlated with tumor size, but neither with the stage of HCC nor the degree of differentiation of HCC. In conclusion, these findings suggest that MAPK/ERK activation in human HCC may play an important role in multistep hepatocarcinogenesis, especially in the progression of HCC; at least in part, through cyclin D1 up-regulation primarily induced by MAPK/ERK via c-Fos.

Natural antibodies to human retrovirus HTLV in a cluster of Japanese patients with adult T cell leukemia

Human T cell lymphoma leukemia virus (HTLV) is a human retrovirus (RNA tumor virus) that was originally isolated from a few patients with leukemias or lymphomas involving mature T lymphocytes. Here we report that the serum of Japanese patients with adult T cell leukemia, but not the serum of tested normal donors, contains high titers of antibodies to HTLV. These observations, together with data from Japan showing that adult T cell leukemia is endemic in southwest Japan, suggest that HTLV is involved in a subtype of human T cell malignancy, including Japanese adult T cell leukemia.

Genetic drift of hepatitis C virus during an 8.2-year infection in a chimpanzee: variability and stability

Extensive variability in genomic sequence, especially at "hypervariable regions" within the NS1/E2 region of the long open reading frame, has been reported for RNA cloned from hepatitis C virus (HCV)-infected humans and chimpanzees. However, genetic changes of HCV occurring during the course of chronic infections in humans and animals have been evaluated only for partial sequences of the HCV genome. We compared two full-length cDNA sequences of HCV obtained from a chimpanzee that was experimentally infected with the HC-J4 strain of HCV: one during the early acute phase and another during a chronic phase 8.2 years afterward. Both isolates had 9412 nucleotides plus the 3' poly(U) tail with varying length organized as follows: 5'UTR (1-341); C (342-914); E (915-1490); NS1/E2 (1491-2528); NS2 (2529-3359); NS3 (3360-5186); NS4 (5187-6380); NS5 (6381-9371); and 3'UTR (9372-9412). We found that 111 (1.18%) of the 9412 nucleotides differed between the two isolates and estimated the mutation rate as approximately 1.44 x 10(-3) base substitutions per site per year. Changes in amino acid coding were associated with 42 mutations, 8 of which were clustered at 5' end of NS1/E2 coding region, so-called "HVR-1." We analyzed the HVR-1 and HVR-2 sequences during the course of infection and found that homologous populations were present at the beginning of infection, and sequence heterogeneity within the region had developed 3.5 years later. Two regions of the HCV genome were characterized by a high degree of conservation of nucleotide sequence: 5'UTR and the 3' half of the NS4 region. The possible secondary structure of the 5'UTR suggests a region for internal ribosomal entry. The 3' half of the NS4 region may also have some specific function which depends upon a strict conservation of nucleotide sequence.

A RUNX2/PEBP2alpha A/CBFA1 mutation displaying impaired transactivation and Smad interaction in cleidocranial dysplasia

Cleidocranial dysplasia (CCD), an autosomal-dominant human bone disease, is thought to be caused by heterozygous mutations in runt-related gene 2 (RUNX2)/polyomavirus enhancer binding protein 2alphaA (PEBP2alphaA)/core-binding factor A1 (CBFA1). To understand the mechanism underlying the pathogenesis of CCD, we studied a novel mutant of RUNX2, CCDalphaA376, originally identified in a CCD patient. The nonsense mutation, which resulted in a truncated RUNX2 protein, severely impaired RUNX2 transactivation activity. We show that signal transducers of transforming growth factor beta superfamily receptors, Smads, interact with RUNX2 in vivo and in vitro and enhance the transactivation ability of this factor. The truncated RUNX2 protein failed to interact with and respond to Smads and was unable to induce the osteoblast-like phenotype in C2C12 myoblasts on stimulation by bone morphogenetic protein. Therefore, the pathogenesis of CCD may be related to the impaired Smad signaling of transforming growth factor beta/bone morphogenetic protein pathways that target the activity of RUNX2 during bone formation.