U6 promoter-driven siRNAs with four uridine 3' overhangs efficiently suppress targeted gene expression in mammalian cells

The first evidence for gene disruption by double-stranded RNA (dsRNA) came from careful analysis in Caenorhabditis elegans. This phenomenon, called RNA interference (RNAi), was observed subsequently in various organisms, including plants, nematodes, Drosophila, and protozoans. Very recently, it has been reported that in mammalian cells, 21- or 22-nucleotide (nt) RNAs with 2-nt 3' overhangs (small inhibitory RNAs, siRNAs) exhibit an RNAi effect. This is because siRNAs are not recognized by the well-characterized host defense system against viral infections, involving dsRNA-dependent inhibition of protein synthesis. However, the current method for introducing synthetic siRNA into cells by lipofection restricts the range of applications of RNAi as a result of the low transfection efficiencies in some cell types and/or short-term persistence of silencing effects. Here, we report a vector-based siRNA expression system that can induce RNAi in mammalian cells. This technical advance for silencing gene expression not only facilitates a wide range of functional analysis of mammalian genes but might also allow therapeutic applications by means of vector-mediated RNAi.     

Induction of the differentiation of human HL-60 promyelocytic leukemia cell line by succinoyl trehalose lipids

Four analogs of succinoyl trehalose lipid-3 (STL-3)with saturated even-number or odd-number carbonchains, and unsaturated or halogenated fatty acidswere examined for their ability to inhibit the growthand induce the differentiation of HL-60 humanpromyelocytic leukemia cells. The optimalconcentration of STL-3 at which such activities wererecognized was closed to the critical micelleconcentration of STL-3. Analog of STL-3 witheven-number or odd-number carbon chain and unsaturatedfatty acids strongly inhibited growth and induced thedifferentiation of HL-60 cells, as evaluated in termsof nitroblue tetrazilium-reducing activity and theappearance of the CD36 antigen. An analog of STL-3with halogenated fatty acids significantly inhibitedproliferation but only induced the differentiation ofHL-60 cells. Our results indicate that the effects ofSTL-3 and its analogs on HL-60 cells depend on thestructure of the hydrophobic moiety of STL-3.These authors contributed equally to this work     

A New Lanternshark <Emphasis Type="Italic">Etmopterus splendidus</Emphasis> from the East China Sea and Java Sea

A new species of the lanternshark Etmopterus splendidus is described. This new species is distinguished from the congeners by the combination of the following characters: distance from snout tip to 1st dorsal spine much less than distance from the spine to upper caudal origin; caudal fin short, much less than head length; dermal denticles on lateral side of trunk with very small, erect thornlike, conical crowns, those on trunk arranged in regular longitudinal rows, and distinctly arranged on interdorsal area and on lateral trunk of interspace between 2nd dorsal and caudal, but not arranged in regular longitudinal rows on dorsal surface of interorbital and o abdomen; color in life purplish-black above and with inconspicuous bluish-black flank marks and three other bluish-black marks at base of caudal fin and along its axis; shape of flank marks narrow anterior to, but broader posterior to pelvic fins.     

Interfractional diaphragm changes during breath-holding in stereotactic body radiotherapy for liver cancer

Aim and background

IGRT based on bone matching may produce a large target positioning error in terms of the reproducibility of expiration breath-holding on SBRT for liver cancer. We evaluated the intrafractional and interfractional errors using the diaphragm position at the end of expiration by utilising Abches and analysed the factor of the interfractional error.

Occurrence of aneuploid progenies from an asynaptic amphidiploid ofScilla scilloides (lindley) druce II. Mechanism of production of the various aneuploid progenies

The mechanism of production of the various aneuploid progenies was clarified in the asynaptic amphidiploid plants (2n=34+4f+2F, AABB) ofScilla scilloides. Its asynaptic nature and chromosomal stickiness lead to the unequal segregation at anaphase I (AI) in PMC's. The observed values in 18 segregation patterns, 17:17 to 0: 34, were different from the expected values estimated from random segregation of chromosomes. Nevertheless, the preferential transmission of special chromosomes among genomes A (x=8=a₁−a₈) and B (x=9=b₁−b₉) had not occurred. As the result of unequal segregation, the pollen grains with various chromosome numbers were observed. Almost all of the 200 pollen grains contained chromosome numbers more than 17 (range 8 to 34). The observed values of each chromosome number were roughly similar to the expected values of containing the complete set of genome A or B in the random distribution without preferential segregation of chromosomes at AI. The difference between the index of polien mitosis and the pollen fertility was significant in the Wilcoxon matched-pairs signed rank test and suggested the selection for some genomically unbalanced pollen grains during maturation. Consequently, viable pollen grains with various chromosome constitutions are a few (mean pollen fertility of 5.8%) but might produce many aneuploids by self- and cross-pollination.     

Activation of human bitter taste receptors by polymethoxylated flavonoids

Tangeretin and nobiletin are polymethoxylated flavonoids in citrus peel. Both tangeretin and nobiletin are bitter; however, their bitterness has not been evaluated using human bitter taste receptors (hTAS2Rs). We screened 25 kinds of hTAS2Rs and found that hTAS2R14 and hTAS2R46 received both compounds.     

Hermaphroditism in the lantern sharkEtmopterus unicolor (Squalidae,chondrichthyes)

Of the 70 specimens of the lantern shark,Etmopterus unicolor, collected in Suruga Bay and adjacent waters 22.9% were abnormal hermaphrodites, 30.0% normal males, and 47.1% normal females. Fifteen hermaphrodites had female reproductive organs composed of normal ovaries, oviducts, nidamentai glands and uteri as well as claspers. The clasper lengths of these hermaphrodites increased rapidly after the sharks reached 510 mm TL, the length about equal to the size at maturity for normal females. The ovary and uterus of abnormal females became mature at a total length greater than 500 mm, whereas the size at maturity was about 500 mm TL for normal females compared to 460 mm TL for normal males. In one specimen, the left gonad contained both ovarian and testicular tissues, the bulk of which was testicular.     

A global double-fluorescent Cre reporter mouse

The Cre/loxP system has been used extensively for conditional mutagenesis in mice. Reporters of Cre activity are important for defining the spatial and temporal extent of Cre-mediated recombination. Here we describe mT/mG, a double-fluorescent Cre reporter mouse that expresses membrane-targeted tandem dimer Tomato (mT) prior to Cre-mediated excision and membrane-targeted green fluorescent protein (mG) after excision. We show that reporter expression is nearly ubiquitous, allowing visualization of fluorescent markers in live and fixed samples of all tissues examined. We further demonstrate that mG labeling is Cre-dependent, complementary to mT at single cell resolution, and distinguishable by fluorescence-activated cell sorting. Both membrane-targeted markers outline cell morphology, highlight membrane structures, and permit visualization of fine cellular processes. In addition to serving as a global Cre reporter, the mT/mG mouse may also be used as a tool for lineage tracing, transplantation studies, and analysis of cell morphology in vivo.