A new class of carriers that transport selective cargo from the trans Golgi network to the cell surface

We have isolated a membrane fraction enriched in a class of transport carriers that form at the trans Golgi network (TGN) and are destined for the cell surface in HeLa cells. Protein kinase D (PKD) is required for the biogenesis of these carriers that contain myosin II, Rab6a, Rab8a, and synaptotagmin II, as well as a number of secretory and plasma membrane‐specific cargoes. Our findings reveal a requirement for myosin II in the migration of these transport carriers but not in their biogenesis per se. Based on the cargo secreted by these carriers we have named them CARTS for CAR riers of the T GN to the cell S urface. Surprisingly, CARTS are distinct from the carriers that transport vesicular stomatitis virus (VSV)‐G protein and collagen I from the TGN to the cell surface. Altogether, the identification of CARTS provides a valuable means to understand TGN to cell surface traffic.     

High-resolution spatiotemporal transcriptome analyses during cellularization of rice endosperm unveil the earliest gene regulation critical for aleurone and starchy endosperm cell fate specification

Journal of Plant Research - The major tissues of the cereal endosperm are the starchy endosperm (SE) in the inner and the aleurone layer (AL) at the outer periphery. The fates of the cells that...     

Identification of Stmm3 locus Conferring Resistance to Late-stage Chemically Induced Skin Papillomas on Mouse Chromosome 4 by Congenic Mappingand Allele-specific Alteration Analysis

Genome-wide association studies have revealed that many low-penetrance cancer susceptibility loci are located throughout the genome; however, a very limited number of genes have been identified so far. Using a forward genetics approach to map such loci in a mouse skin cancer model, we previously identified strong genetic loci conferring resistance to chemically induced skin papillomas on chromosome 4 and 7 with a large number of [(FVB/N × MSM/Ms) F₁ × FVB/N] backcross mice. In this report, we describe a combination of congenic mapping and allele-specific alteration analysis of the loci on chromosome 4. We used linkage analysis and a congenic mouse strain, FVB.MSM-Stmm3 to refine the location of Stmm3 (Skin tumor modifier of MSM 3) locus within a physical interval of about 34 Mb on distal chromosome 4. In addition, we used patterns of allele-specific imbalances in tumors from N₂ and N₁₀ congenic mice to narrow down further the region of Stmm3 locus to a physical distance of about 25 Mb. Furthermore, immunohistochemical analysis showed papillomas from congenic mice had less proliferative activity. These results suggest that Stmm3 responsible genes may have an influence on papilloma formation in the two-stage skin carcinogenesis by regulating papilloma growth rather than development.     

Identification of a multi-component berberine 11-hydroxylase from Burkholderia sp. strain CJ1

ABSTRACT

Berberine (BBR) is a protoberberine alkaloid extracted from plants such as Coptis japonica (Ranunculaceae). In a previous report, we demonstrated the existence of a 11-hydroxylation pathway employed by BBR-utilizing bacteria for metabolism of BBR. In the present study, we report the identification of the genes brhA, brhB, and brhC as encoding a multicomponent BBR 11-hydroxylase in Burkholderia sp. strain CJ1. BrhA is belonging to the Rieske non-heme iron oxygenase (RO) family, a class of enzymes known to catalyze the first step in bacterial aromatic-ring hydroxylation. We further demonstrate that BrhA activity requires BrhB (ferredoxin reductase) and BrhC (ferredoxin) as electron transport chain components. A BLAST search revealed that BrhA exhibits 38% and 33% sequence identity to dicamba O-demethylase (DdmC; AY786443) and chloroacetanilide herbicides N-dealkylase (CndA; KJ461679), respectively. To our knowledge, this work represents the first report of a bacterial oxygenase catalyzing the metabolism of a polycyclic aromatic-ring alkaloid.

Abbreviations: BBR: berberine; D-BBR: demethyleneberberine; H-BBR: 11-hydroxyberberine; HD-BBR: 11-hydroxydemethyleneberberine; HDBA: 2-hydroxy-3,4-dimethoxybenzeneacetic acid; PAL: palmatine; H-PAL: 11-hydroxypalmatine; BRU: berberrubine; Fd: ferredoxin; FdR: ferredoxin reductase; ETC: electron transport chain     

Topological persistency found in aggregations of coastal sea skater,Halobates japonicus Esaki, 1924 (Hemiptera: Gerridae), based on genetic relationships amongst three aggregations in Ishigaki Island,Japan

Sea skaters, genus Halobates Eschscholtz, 1822, are the only marine insects living in mangrove beds and the tide pools of coral reefs, both of which provide dramatically variable habitats daily by virtue of tide-driven changes in surface level. Females of H. japonicus Esaki, 1924 were collected from three distinct aggregations in a single bay (24°27′5″N, 124°8′40″E) on 1–5 November 2006. Two aggregations were formed in respective tide pools of the coral reef and one was formed in the mangrove beds. Amplified fragment length polymorphism markers were used to detect the persistency of each aggregation at a mesoscale. The results suggested that H. japonicus repeatedly immigrated from outside the bay to establish a meta-population of several deme groups. Aggregations along the coastline had some persistency to the line itself and had little tendency to cross to the opposite shore, even when the distance was short.     

Laboratory breeding of the red-backed vole (Clethrionomys rufocanus bedfordiae)]

Laboratory matings were attempted to establish breeding colonies of red-backed voles (Clethrionomys rufocanus bedformidae) as experimental animals. For these mating, 10 pairs of red-backed voles which were captured in the Tohbetsu region of Hokkaido, Japan and their litters were used. In the results for two years, 1987 to 1988, the rates of pregnancy, birth and weaning were 35.4%, 94.5% and 79.5%, respectively. The mean litter size was 5:1 +/- 1.6 with a range of 1 to 9. The mean gestation period was 20.0 +/- 0.7 days with a range of 18 to 22. These results suggest that planned production of red-backed voles in the laboratory is possible. To determine intraregional variations of red-backed voles with a view to the establishment of a strain by inbreeding, restriction patterns of mitochondrial DNAs using seven restriction endonucleases were compared. Four different patterns were obtained from wild red-backed voles used in the present study.     

Lung Surfactant Levels are Regulated by Ig-Hepta/GPR116 by Monitoring Surfactant Protein D

Lung surfactant is a complex mixture of lipids and proteins, which is secreted from the alveolar type II epithelial cell and coats the surface of alveoli as a thin layer. It plays a crucial role in the prevention of alveolar collapse through its ability to reduce surface tension. Under normal conditions, surfactant homeostasis is maintained by balancing its release and the uptake by the type II cell for recycling and the internalization by alveolar macrophages for degradation. Little is known about how the surfactant pool is monitored and regulated. Here we show, by an analysis of gene-targeted mice exhibiting massive accumulation of surfactant, that Ig-Hepta/GPR116, an orphan receptor, is expressed on the type II cell and sensing the amount of surfactant by monitoring one of its protein components, surfactant protein D, and its deletion results in a pulmonary alveolar proteinosis and emphysema-like pathology. By a coexpression experiment with Sp-D and the extracellular region of Ig-Hepta/GPR116 followed by immunoprecipitation, we identified Sp-D as the ligand of Ig-Hepta/GPR116. Analyses of surfactant metabolism in Ig-Hepta^+/+ and Ig-Hepta^−/− mice by using radioactive tracers indicated that the Ig-Hepta/GPR116 signaling system exerts attenuating effects on (i) balanced synthesis of surfactant lipids and proteins and (ii) surfactant secretion, and (iii) a stimulating effect on recycling (uptake) in response to elevated levels of Sp-D in alveolar space.     

WUSCHEL-RELATED HOMEOBOX4 Is Involved in Meristem Maintenance and Is Negatively Regulated by the CLE Gene FCP1 in Rice

The shoot apical meristem is the ultimate source of the cells that constitute the entire aboveground portion of the plant body. In Arabidopsis thaliana, meristem maintenance is regulated by the negative feedback loop of WUSCHEL-CLAVATA (WUS-CLV). Although CLV-like genes, such as FLORAL ORGAN NUMBER1 (FON1) and FON2, have been shown to be involved in maintenance of the reproductive meristems in rice (Oryza sativa), current understanding of meristem maintenance remains insufficient. In this article, we demonstrate that the FON2-LIKE CLE PROTEIN1 (FCP1) and FCP2 genes encoding proteins with similar CLE domains are involved in negative regulation of meristem maintenance in the vegetative phase. In addition, we found that WUSCHEL-RELATED HOMEOBOX4 (WOX4) promotes the undifferentiated state of the meristem in rice and that WOX4 function is associated with cytokinin action. Consistent with similarities in the shoot apical meristem phenotypes caused by overexpression of FCP1 and downregulation of WOX4, expression of WOX4 was negatively regulated by FCP1 (FCP2). Thus, FCP1/2 and WOX4 are likely to be involved in maintenance of the vegetative meristem in rice.     

Expression and localization of aquaporins in rat gastrointestinal tract

A family of water-selective channels, aquaporins (AQP), has beendemonstrated in various organs and tissues. However, the localizationand expression of the AQP family members in the gastrointestinal tracthave not been entirely elucidated. This study aimed to demonstrate theexpression and distribution of several types of the AQP family and tospeculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1-5 and AQP8 was examined in various portions through the gastrointestinal tract.AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon,and their expression was relatively intense in the small intestine andcolon. In contrast, AQP4 mRNA was selectively expressed in the stomachand small intestine and AQP8 mRNA in the jejunum and colon.Immunohistochemistry and in situ hybridization demonstrated cellularlocalization of these AQP in these portions. AQP1 was localized onendothelial cells of lymphatic vessels in the submucosa and laminapropria throughout the gastrointestinal tract. AQP3 was detected on thecircumferential plasma membranes of stratified squamous epithelialcells in the esophagus and basolateral membranes of cardiac glandepithelia in the lower stomach and of surface columnar epithelia in thecolon. However, AQP3 was not apparently detected in the smallintestine. AQP4 was present on the basolateral membrane of the parietalcells in the lower stomach and selectively in the basolateral membranesof deep intestinal gland cells in the small intestine. AQP8 mRNAexpression was demonstrated in the absorptive columnar epithelial cellsof the jejunum and colon by in situ hybridization. These findings mayindicate that water crosses the epithelial layer through these waterchannels, suggesting a possible role of the transcellular route forwater intake or outlet in the gastrointestinal tract.