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81.
MCPIP1 ribonuclease antagonizes dicer and terminates microRNA biogenesis through precursor microRNA degradation 总被引:2,自引:0,他引:2
Suzuki HI Arase M Matsuyama H Choi YL Ueno T Mano H Sugimoto K Miyazono K 《Molecular cell》2011,44(3):424-436
MicroRNAs (miRNAs) are versatile regulators of gene expression and undergo complex maturation processes. However, the mechanism(s) stabilizing or reducing these small RNAs remains poorly understood. Here we identify mammalian immune regulator MCPIP1 (Zc3h12a) ribonuclease as a broad suppressor of miRNA activity and biogenesis, which counteracts Dicer, a central ribonuclease in miRNA processing. MCPIP1 suppresses miRNA biosynthesis via cleavage of the terminal loops of precursor miRNAs (pre-miRNAs). MCPIP1 also carries a vertebrate-specific oligomerization domain important for pre-miRNA recognition, indicating its recent evolution. Furthermore, we observed potential antagonism between MCPIP1 and Dicer function in human cancer and found a regulatory role of MCPIP1 in the signaling axis comprising miR-155 and its target c-Maf. These results collectively suggest that the balance between processing and destroying ribonucleases modulates miRNA biogenesis and potentially affects pathological miRNA dysregulation. The presence of this abortive processing machinery and diversity of MCPIP1-related genes may imply a dynamic evolutional transition of the RNA silencing system. 相似文献
82.
Species of predatory Coleoptera have become abundant in new geographic regions recently, raising concerns for invaded ecosystems.
We address this topic by focusing on invasive alien ladybird beetles (Coccinellidae; known also as ladybugs). Humans appear
directly or indirectly responsible for all or most ladybird invasions. Factors hypothesized to have promoted ladybird invasions
include genetic diversity (e.g., for polymorphism), phenotypic plasticity, adaptation and genetic shift, generalized diet
and habitat preferences, flexible life history and reproduction, large body size, and release from enemies. Factors such as
climate, habitat and prey availability, and biotic resistance may sometimes prevent or slow ladybird invasions. Indigenous
species (e.g., herbivores) may suffer from invasions, and biological control programs may be affected. Species of indigenous
ladybirds throughout the world are reported to have declined in abundance following ladybird invasions, with increased competition
and/or intraguild predation most often hypothesized or inferred. Similar recent studies especially of ground beetles (Carabidae)
also make clear the potential of invasive alien predatory Coleoptera to disrupt invaded natural and agricultural ecosystems. 相似文献
83.
Morimoto T Kojima Y Toki T Komeda Y Yoshiyama M Kimura K Nirasawa K Kadowaki T 《Ecology and evolution》2011,1(2):201-217
The honey bee is a major insect used for pollination of many commercial crops worldwide. Although the use of honey bees for pollination can disrupt the habitat, the effects on their physiology have never been determined. Recently, honey bee colonies have often collapsed when introduced in greenhouses for pollination in Japan. Thus, suppressing colony collapses and maintaining the number of worker bees in the colonies is essential for successful long-term pollination in greenhouses and recycling of honey bee colonies. To understand the physiological states of honey bees used for long-term pollination in greenhouses, we characterized their gene expression profiles by microarray. We found that the greenhouse environment changes the gene expression profiles and induces immune-suppression and oxidative stress in honey bees. In fact, the increase of the number of Nosema microsporidia and protein carbonyl content was observed in honey bees during pollination in greenhouses. Thus, honey bee colonies are likely to collapse during pollination in greenhouses when heavily infested with pathogens. Degradation of honey bee habitat by changing the outside environment of the colony, during pollination services for example, imposes negative impacts on honey bees. Thus, worldwide use of honey bees for crop pollination in general could be one of reasons for the decline of managed honey bee colonies. 相似文献
84.
85.
Blinks and saccades cause transient interruptions of visual input. To investigate how such effects influence our perceptual
state, we analyzed the time courses of blink and saccade rates in relation to perceptual switching in the Necker cube. Both
time courses of blink and saccade rates showed peaks at different moments along the switching process. A peak in blinking
rate appeared 1,000 ms prior to the switching responses. Blinks occurring around this peak were associated with subsequent
switching to the preferred interpretation of the Necker cube. Saccade rates showed a peak 150 ms prior to the switching response.
The direction of saccades around this peak was predictive of the perceived orientation of the Necker cube afterwards. Peak
blinks were followed and peak saccades were preceded by transient parietal theta band activity indicating the changing of
the perceptual interpretation. Precisely-timed blinks, therefore, can initiate perceptual switching, and precisely-timed saccades
can facilitate an ongoing change of interpretation. 相似文献
86.
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88.
Jodo A Kitahashi T Taniyama S Bhandari RK Ueda H Urano A Ando H 《Zoological science》2005,22(12):1331-1338
Seasonal variation in the expression of five subtypes of gonadotropin-releasing hormone receptor (GnRH-R) genes, designated as msGnRH-R1, -R2, -R3, -R4, and -R5, was examined in the brain of masu salmon (Oncorhynchus masou). In addition, responses of these genes to GnRH were examined in a GnRH analog (GnRHa) implantation experiment. Brain samples were collected one week after the implantation every month from immaturity through spawning. The absolute amount of GnRH-R mRNA in single forebrains was determined by real-time PCR assays. Among the five genes, R4 and R5 were dominantly expressed in both sexes. R1, R4, and R5 mRNAs showed similar changes throughout the experimental period in both sexes. Levels tended to be high in winter and low in the pre-spawning season, followed by elevations in the spawning period. The mRNA levels had weak to moderate negative correlations with the plasma level of estradiol-17beta (E2) in females. The effects of GnRHa on msGnRH-R mRNAs were not apparent for all the subtypes. These results indicate that the msGnRH-R1, -R4, and -R5 genes are synchronously expressed during sexual maturation. There was a trend toward decreased levels of their expression prior to the spawning period and then increased levels at spawning, possibly causing GnRH target neurons to sensitize to a GnRH stimulus. Furthermore, E2 may be involved in msGnRH-R gene expression in the brain of female masu salmon during sexual maturation. 相似文献
89.
Tadano M Edamatsu H Minamisawa S Yokoyama U Ishikawa Y Suzuki N Saito H Wu D Masago-Toda M Yamawaki-Kataoka Y Setsu T Terashima T Maeda S Satoh T Kataoka T 《Molecular and cellular biology》2005,25(6):2191-2199
Phospholipase Cepsilon is a novel class of phosphoinositide-specific phospholipase C, identified as a downstream effector of Ras and Rap small GTPases. We report here the first genetic analysis of its physiological function with mice whose phospholipase Cepsilon is catalytically inactivated by gene targeting. The hearts of mice homozygous for the targeted allele develop congenital malformations of both the aortic and pulmonary valves, which cause a moderate to severe degree of regurgitation with mild stenosis and result in ventricular dilation. The malformation involves marked thickening of the valve leaflets, which seems to be caused by a defect in valve remodeling at the late stages of semilunar valvulogenesis. This phenotype has a remarkable resemblance to that of mice carrying an attenuated epidermal growth factor receptor or deficient in heparin-binding epidermal growth factor-like growth factor. Smad1/5/8, which is implicated in proliferation of the valve cells downstream of bone morphogenetic protein, shows aberrant activation at the margin of the developing semilunar valve tissues in embryos deficient in phospholipase Cepsilon. These results suggest a crucial role of phospholipase Cepsilon downstream of the epidermal growth factor receptor in controlling semilunar valvulogenesis through inhibition of bone morphogenetic protein signaling. 相似文献
90.