Characterization and imprinting status of OBPH1/Obph1 gene: implications for an extended imprinting domain in human and mouse

Human 11p15.5, as well as its orthologous mouse 7F4/F5, is known as the imprinting domain extending from IPL/Ipl to H19. OBPH1 and Obph1 are located beyond the presumed imprinting boundary on the IPL/Ipl side. We determined full-length cDNAs and complete genomic structures of both orthologues. We also investigated their precise imprinting and methylation status. The orthologues resembled each other in genomic structure and in the position of the 5' CpG island and were expressed ubiquitously. OBPH1 and Obph1 were predominantly expressed from the maternal allele only in placenta, with hypo- and not differentially methylated 5' CpG islands in both species. These results suggested that the imprinting domain would extend beyond the presumed imprinting boundary and that methylation of the 5' CpG island was not associated with the imprinting status in either species. It remains to be elucidated whether the gene is under the control of the KIP2/LIT1 subdomain or is regulated by a specific mechanism. Analysis of the precise genomic sequence around the region should help resolve this question.     

Isolation and identification of EG-VEGF/prokineticins as cognate ligands for two orphan G-protein-coupled receptors

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF, identical to prokineticin 1) is a novel peptide recently identified as a selective mitogen for endocrine gland endothelial cells. The present study demonstrates that EG-VEGF/prokineticin 1 and a peptide closely related to EG-VEGF, prokineticin 2, are cognate ligands of two orphan G-protein-coupled receptors designated ZAQ (=EG-VEGF/PK-R1) and I5E (=EG-VEGF/PK-R2). EG-VEGF/prokineticin 1 and prokineticin 2 induced a transient increase in intracellular calcium ion concentration ([Ca(2+)](i)) with nanomolar potency in Chinese hamster ovary (CHO) cells expressing EG-VEGF/PK-R1 and -R2 and bind to these cells with high affinity and with different receptor selectivity. EG-VEGF/prokineticins provoke rapid phosphorylation of p44/42 MAP kinase and DNA synthesis in the bovine adrenal capillary endothelial cells (BACE). The mRNAs of both EG-VEGF/PK-R1 and -R2 were expressed in BACE. The identification of the receptors for EG-VEGF/prokineticins may provide a novel molecular basis for the regulation of angiogenesis in endocrine glands.     

The obesity in bilateral ovariectomized rats is related to a decrease in the expression of leptin receptors in the brain.

We investigated the expression levels of leptin receptors in the brain of ovariectomized (OVX) rats. The mean expression level of ob mRNA in adipose tissues of OVX rats was significantly (P < 0.01) lower than that in the SHAM operation group rats, and the mean body weight of OVX rats was significantly (P < 0.01) greater than that in the SHAM group rats. However, there were no differences between serum leptin concentrations in these two groups. The mean level of leptin receptor (OB-R) mRNA expression in the brain tissue and the mean level of long form type OB-R (OB-RL) mRNA expression in the hypothalamus of the OVX rats were significantly (P < 0.05) lower than those in the SHAM group rats. These changes were cancelled by supplementation with 17 beta-estradiol in OVX rats. These results suggested that not only changes in the expression level of ob mRNA in adipose tissue and the serum leptin concentration but also changes in the OB-R mRNA in the brain are involved in the body weight increase in OVX rats and that a decrease in OB-R makes transmission of signals to suppress the amount of food intake difficult, thus leading to an increase in body weight.     

Characterization of Epstein-Barr virus (EBV)-positive NK cells isolated from hydroa vacciniforme-like eruptions

Recently, the involvement of Epstein-Barr virus (EBV) in hydroa vacciniforme (HV)-like eruptions has been suggested. To elucidate the role of EBV in this disease, we isolated EBV-infected cell clones from peripheral blood mononuclear cells (PBMC) and the skin lesions of a patient with HV-like eruptions; cells isolated from PBMC were designated SNK-12, and those from the eruption SNK-11. Both cells expressed CD16, CD56, and HLA-DR and had germline configurations of the T-cell receptor and the immunoglobulin genes, indicating that the cell clones were of NK cell lineage. The analysis of EBV terminal repeats indicated that the cells were monoclonal, had identical clonality, and originated from EBV-positive cells in the PBMC and eruption. Both clones expressed EBNA-1, but not EBNA-2. Although LMP-1 was weakly detected in SNK-11, no LMP-1 was detected in SNK-12. Interestingly, EBV-infected cells required less IL-2 for in vitro growth in the later phase of this disease and this appeared to correlate with the expression of LMP-1, suggesting that the proliferative capacity of the EBV-positive NK cells increased during the time course of the disease, and LMP-1 expression might be responsible for that. This is the first report of the isolation of EBV-infected cells from the skin lesions of HV-like eruptions and strongly suggests that the HV-like eruption in the patient was caused by clonal NK cells with latent EBV infection.     

Differential contributions of condensin I and condensin II to mitotic chromosome architecture in vertebrate cells

The canonical condensin complex (henceforth condensin I) plays an essential role in mitotic chromosome assembly and segregation from yeast to humans. We report here the identification of a second condensin complex (condensin II) from vertebrate cells. Condensins I and II share the same pair of structural maintenance of chromosomes (SMC) subunits but contain different sets of non-SMC subunits. siRNA-mediated depletion of condensin I- or condensin II-specific subunits in HeLa cells produces a distinct, highly characteristic defect in chromosome morphology. Simultaneous depletion of both complexes causes the severest defect. In Xenopus egg extracts, condensin I function is predominant, but lack of condensin II results in the formation of irregularly shaped chromosomes. Condensins I and II show different distributions along the axis of chromosomes assembled in vivo and in vitro. We propose that the two condensin complexes make distinct mechanistic contributions to mitotic chromosome architecture in vertebrate cells.     

Sculpting the cardiac outflow tract

The cardiac outflow tract is the site of anomalies that affect a substantial proportion of individuals with congenital heart defects. The morphogenesis of this site is complex, and requires coordinated development of many cell types and tissues. It is therefore not surprising that developmental mistakes arise here, and that the steps and mechanisms of morphogenesis are still controversial and poorly understood, despite advances in molecular techniques. Recent findings have provided new insight into mechanisms of outflow tract morphogenesis, including clarification of its origins and the fate of cardiomyocytes, as well as invading cell populations. Application of new and old techniques and a wide range of approaches to tackle the unanswered questions about the outflow tract calls for collaboration among investigators from different disciplines including anatomists, physiologists, and molecular biologists.     

The spindle pole body of the pathogenic yeast Exophiala dermatitidis: variation in morphology and positional relationship to the nucleolus and the bud in interphase cells

The spindle pole body (SPB) in the interphase cell of the pathogenic yeast Exophiala dermatitidis was studied in detail. The SPB was located on the outer nuclear envelope and was 342 +/- 86 nm long in a haploid strain. It consisted of two disk elements that measured 151 +/- 43 nm in diameter and 103 +/- 17 nm in thickness, connected by a rod-shaped midpiece that measured 56 +/- 20 nm in length and 37 +/- 9 nm in diameter. There were considerable variations in size and morphology of interphase SPB. Some disk elements appeared spherical but others were more flattened, and there was variation in electron density. A few SPBs did not have the midpiece. The SPB of a diploid strain was 486 +/- 118 nm long, thus significantly bigger than that of the haploid strain. The SPB tended to be localized away from the nucleolus (110 +/- 48 degrees), but close to the bud (78 +/- 45 degrees). The present study highlights the necessity of observing a large number of micrographs in three-dimensions to describe accurately the ultrastructure of the SPB in yeast.     

Community-level flowering phenology and fruit set: Comparative study of 25 woody species in a secondary forest in Japan

We investigated the flowering phenology, pollinator visitation, and fruit set of 25 animal-pollinated woody species in a warm temperate secondary forest in Japan. Various species flowered sequentially from February to October. The principal pollinators were bumblebees, honey-bees, flies and/or beetles and birds; bumblebees and flies/beetles pollinated most trees. The duration of flowering was shorter for species that bloomed in the middle of the season than it was for species that bloomed earlier or later in the season. The timing of flowering was more synchronous within species that had a shorter flowering duration; this was also detected when phylogenetically independent contrasts were calculated. This could be important for the effective pollination of species with a short flowering duration because such species bloom sequentially over a short period of less than 1month around May. Fruit set was related not to pollinator type, sex expression, flowering sequence (in order of the date of peak flowering) or flowering duration, but to the relative abundance of the species in the forest. This correlation was detected for fly- and beetle-pollinated species but not for bumblebee-pollinated species. Thus, relatively rare plant species with opportunistic pollinators might experience limited fruit set because of insufficient pollinator services. Bagging experiments conducted on eight hermaphrodite species revealed that the fruit set of bagged flowers was nearly zero, lower than that of control flowers. These results indicate the importance of pollinators for successful reproduction and thus for the coexistence of plants in this secondary forest.     

Polyphenols from some foodstuffs as inhibitors of ovalbumin permeation through caco-2 cell monolayers

Some spices showed high inhibitory activity against ovalbumin permeation through Caco-2 cell monolayers. Pimentol from allspice, rosmarinic acid and luteolin-7-O-beta-glucuronide from thyme, quercetin-3-O-beta-glucuronide from coriander and rutin from tarragon were identified as the active principles. A structure-activity relationship study among the active isolates and their related compounds indicated that the presence of a catechol structure played an important role in the inhibitory activity of each compound.