• Title, Summary, Keyword: piRNA

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A novel model of THO/TREX loading onto target RNAs in metazoan gene expression

  • Hur, Junho K.;Chung, Yun Doo
    • BMB Reports
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    • v.49 no.7
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    • pp.355-356
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    • 2016
  • The THO/TREX complex consists of several conserved subunits and is required for mRNA export. In metazoans, THO/TREX binds a subset of mRNAs during RNA splicing, and facilitates their nuclear export. How THO/TREX selects RNA targets is, however, incompletely understood. In our recent study, we reported that THO is loaded onto Piwi-interacting RNA (piRNA) precursor transcripts independent of splicing, and facilitates convergent transcription in Drosophila ovary. The precursors are later processed into mature piRNAs, small noncoding RNAs that silence transposable elements (TEs). We observed that piRNAs originating from dual-strand clusters, where precursors are transcribed from both strands, were specifically affected by THO mutation. Analysis of THO-bound RNAs showed enrichment of dual-strand cluster transcripts. Interestingly, THO loading onto piRNA precursors was dependent on Cutoff (Cuff), which comprises the Rhino-Deadlock-Cutoff (RDC) complex that is recruited to dual-strand clusters by recognizing H3K9me3 and licenses convergent transcription from he cluster. We also found that THO mutation affected transcription from dual-strand clusters. Therefore, we concluded that THO/TREX is recruited to dual-strand piRNA clusters, independent of splicing events, via multi-protein interactions with chromatin structure. Then, it facilitates transcription likely by suppressing premature termination to ensure adequate expression of piRNA precursors.

PIWI Proteins and piRNAs in the Nervous System

  • Kim, Kyung Won
    • Molecules and Cells
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    • v.42 no.12
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    • pp.828-835
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    • 2019
  • PIWI Argonaute proteins and Piwi-interacting RNAs (piRNAs) are expressed in all animal species and play a critical role in cellular defense by inhibiting the activation of transposable elements in the germline. Recently, new evidence suggests that PIWI proteins and piRNAs also play important roles in various somatic tissues, including neurons. This review summarizes the neuronal functions of the PIWI-piRNA pathway in multiple animal species, including their involvement in axon regeneration, behavior, memory formation, and transgenerational epigenetic inheritance of adaptive memory. This review also discusses the consequences of dysregulation of neuronal PIWI-piRNA pathways in certain neurological disorders, including neurodevelopmental and neurodegenerative diseases. A full understanding of neuronal PIWI-piRNA pathways will ultimately provide novel insights into small RNA biology and could potentially provide precise targets for therapeutic applications.

Changes of splenocyte $IFN-{\gamma}$ mRNA synthesis in rats infected with Paragonimus westermani

  • Cho, Jun-Kyong;KWon, Hye-Soo;Joo, Kyoung-Hwan;Lee, Joon-Sang;Cho, Sung-Weon
    • The Korean Journal of Parasitology
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    • v.37 no.4
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    • pp.285-287
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    • 1999
  • Changes in the expression level of splenocyte $IFN-{\gamma}$mRNA of Sprague-Dawley (SD) rats infected with Paragonimus westermani were analyzed by competitive reverse transcription-polymerase chain reaction (RT-PCR) followed by southern blot. The template RNA was extracted from the splenocytes of rats infected with 20 metacercariae of P. westermani. The products of competitive RT-PCR were subjected to southern blot and enhanced chemiluminescence (ECL), and analyzed with a densitometer. In comparison with that of uninfected control rat splenocytes (value of 1), the levels of mRNA expression of $IFN-{\gamma}$had changed to 0.747 at 1 week post infection (PI), 0.00175 at 2 week PI, 0.0217 at 3 week PI, 0.194 at 4 week PI and then to 0.537 at 5 week PI. The level at 7 week PI had returned to 1.25, comparable with that of uninfected rats. These results show that, when infected with p. westermani, the levels of $IFN-{\gamma}$ mRNA of SD rat splenocytes were remarkably reduced by more than 500 times at 2 week PI and restored to normal level at 7 week PI.

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Different Phosphate Transport in the Duodenum and Jejunum of Chicken Response to Dietary Phosphate Adaptation

  • Fang, Rejun;Xiang, Zhifeng;Cao, Manhu;He, Jia
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.10
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    • pp.1457-1465
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    • 2012
  • Intestinal phosphate (Pi) absorption across the apical membrane of small intestinal epithelial cells is mainly mediated by the type IIb Na-coupled phosphate co-transporter (NaPi-IIb), but its expression and regulation in the chicken remain unclear. In the present study, we investigated the mRNA and protein levels of NaPi-IIb in three regions of chicken small intestine, and related their expression levels to the rate of net phosphate absorption. Our results showed that maximal phosphate absorption occurs in the jejunum, however the highest expression levels of NaPi-IIb mRNA and protein occurs in the duodenum. In response to a low-Pi diet (TP 0.2%), there is an adaptive response restricted to the duodenum, with increased brush border membrane (BBM) Na-Pi transport activity and NaPi-IIb protein and mRNA abundance. However, when switched from a low-(TP 0.2%) to a normal diet (TP 0.6%) for 4 h, there is an increase in BBM NaPi-IIb protein abundance in the jejunum, but no changes in BBM NaPi-IIb mRNA. Therefore, our study indicates that Na-Pi transport activity and NaPi-IIb protein expression are differentially regulated in the duodenum vs the jejunum in the chicken.

Effects of 3-methylcholanthrene on the Expression of Drug Metabolizing Enzyme Genes in Monkey Intestine (원숭이 소장 약물대사효소 유전자 발현에 미치는 3-methylcholanthrene 영향)

  • 이경원;아사오카;신윤용
    • Environmental Mutagens and Carcinogens
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    • v.24 no.1
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    • pp.19-24
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    • 2004
  • In order to understand the mechanism of the regulation of drug metabolizing enzyme gene expression, we have studied the induction of CYP1A1 and $GST\alpha,$ $\mu,$ $\pi$ enzymes in Japanese monkey and rhesus monkey after the treatment with 3-methylcholanthrene (3MC) and di-n-butyl phthalate (DBP) and bisphenol A (BPA). The levels of mRNA were measured by RT-PCR in brain, intestine and liver. In the case of adult monkey, treatment with 3MC induced CYP1A1 mRNA in intestine by 11-fold. The treatment with DBP induced CYP1A1 mRNA. Effects of 3MC and DBP on GST mRNA expression was not clear. But $GST\mu$ was slightly inhibited by the treatment with 3MC and DBP. $GST\alpha$ was induced in intestine by 1.5-fold. $GST\pi$ was slightly induced by the treatment with 3MC and DBP in intestine. In the case of fetus monkey, the basal levels of fetus CYP1A1 mRNA and GSTs mRNA were relatively low compared to adult monkey. As the age of monkey increased, the basal levels of CYP1A1 mRNA were also increased. 3MC induced the expression of CYP1A1 mRNA didn't significantly induce CYP1A1 mRNA in intestine. The levels of $GST\mu$ and $GST\pi$ were not changed by the treatment with 3MC and DBP. $GST\pi$ was slightly induced by the treatment with 3MC and DBP.

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The Influence of Dietary Calcium and Phosphorus Imbalance on Intestinal NaPi-IIb and Calbindin mRNA Expression and Tibia Parameters of Broilers

  • Li, Jianhui;Yuan, Jianmin;Guo, Yuming;Sun, Qiujuan;Hu, Xiaofei
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.4
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    • pp.552-558
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    • 2012
  • A $2{\times}2$ factorial experiment was conducted to study the effect of dietary calcium and non-phytate phosphorus (nPP) imbalance on calbindin and NaPi-IIb mRNA levels in the small intestine and tibia parameters of broiler chicks. One hundred and forty four 1-d-old Arbor Acres male broiler chicks were divided into four treatments consisted of six replicates with six chicks each. The two dietary calcium levels were 1.10% and 0.60%, and two dietary nPP levels were 0.50% and 0.27%. Results showed that a high Ca/nPP ratio diet (4.07:1) significantly depressed feed intake and weight gain of broilers (p<0.05), but a lower Ca:nPP ratio (1.2:1) had no influence (p>0.05). Low-Ca with low-P diet resulted in low tibia minerals and tibia breaking strength of broilers, and all the tibia parameters were further decreased when the dietary ratio of Ca to P was relative higher. Low dietary Ca or P up-regulated the calbindin and NaPi-IIb mRNA expression levels. Low Ca with normal P diet up-regulated duodenal calbindin mRNA expression level to the greatest extent. Low P with a normal Ca diet significantly enhanced NaPi-IIb mRNA expression level to the highest extent. These results suggest that the calbindin and NaPi-IIb mRNA expression were enhanced by the imbalance between dietary Ca and nPP, and their expression were not only influenced by Ca or nPP level, but also the ratio of Ca:nPP.

Effects of TAM (Taraxacum mongolicum) on Th2 Cytokine Production in MC/9 Mast Cells (포공영(蒲公英)이 MC/9 mast cell에서의 Th2 cytokine 발현에 미치는 영향)

  • Jang, Moon-Hee;Choi, Jae-Song;Bae, Na-Young;Ahn, Teak-Won
    • Journal of Sasang Constitutional Medicine
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    • v.24 no.1
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    • pp.54-65
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    • 2012
  • 1. Objective : The purpose of this study is to investigate the effects of TAM (Taraxacum mongolicum) on Th2 cytokine production in MC/9 mast cells. 2. Methods : The effects of TAM was analyzed by ELISA and Real-time PCR in MC/9 mast cells. Levels of IL-5, IL-13 were measured using enzyme-linked immunosorbent assays(ELISA). mRNA levels of IL-4, IL-5, IL-6, IL-13 were analyzed with Real-time PCR. 3. Results : 1) TAM inhibited the IL-4 production significantly in comparison to PI-control group at concentration of $50{\mu}g/ml$, $100{\mu}g/ml$, $200{\mu}g/ml$. 2) TAM inhibited the IL-13 production significantly in comparison to PI-control group at concentration of $50{\mu}g/ml$, $100{\mu}g/ml$, $200{\mu}g/ml$. 3) TAM inhibited the IL-4 mRNA expression significantly in comparison to PI-control group at concentration of $100{\mu}g/ml$. 4) TAM inhibited the IL-5 mRNA expression significantly in comparison to PI-control group at concentration of $50{\mu}g/ml$, $100{\mu}g/ml$. 5) TAM inhibited the IL-6 mRNA expression significantly in comparison to PI-control group at concentration of $100{\mu}g/ml$. 6) TAM inhibited the IL-13 mRNA expression significantly in comparison to PI-control group at concentration of $100{\mu}g/ml$. 4. Conclusions : These results indicate that TAM (Taraxacum mongolicum) has the effect of decreasing the Th2 cytokine production in the MC/9 mast cell.

Roles for the lipid-signaling enzyme MitoPLD in mitochondrial dynamics, piRNA biogenesis, and spermatogenesis

  • Gao, Qun;Frohman, Michael A.
    • BMB Reports
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    • v.45 no.1
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    • pp.7-13
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    • 2012
  • Phospholipase D (PLD), a superfamily of signaling enzymes that most commonly generate the lipid second messenger Phosphatidic Acid (PA), is found in diverse organisms from bacteria to man and functions in multiple cellular pathways. A fascinating member of the family, MitoPLD, is anchored to the mitochondrial surface and has two reported roles. In the first role, MitoPLD-generated PA regulates mitochondrial shape through facilitating mitochondrial fusion. In the second role, MitoPLD performs a critical function in a pathway that creates a specialized form of RNAi required by developing spermatocytes to suppress transposon mobilization during meiosis. This spermatocyte-specific RNAi, known as piRNA, is generated in the nuage, an electron-dense accumulation of RNA templates and processing proteins that localize adjacent to mitochondria in a structure also called intermitochondrial cement. In this review, we summarize recent findings on these roles for MitoPLD functions, highlighting directions that need to be pursued to define the underlying mechanisms.

Identification of piRNAs in Hela cells by massive parallel sequencing

  • Lu, Yilu;Li, Chao;Zhang, Kun;Sun, Huaqin;Tao, Dachang;Liu, Yunqiang;Zhang, Sizong;Ma, Yongxin
    • BMB Reports
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    • v.43 no.9
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    • pp.635-641
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    • 2010
  • Piwi proteins and Piwi-interacting RNAs (piRNAs) have been implicated in transposon control in germline from Drosophila to mammals. To examine the profile of small RNA expression in human cancer cells and explore difference in small RNA transcriptome, small RNA libraries prepared from wildtype, HILI overexpressed and HILI knockdowned Hela cells were sequenced using Solexa technology. piRNAs and other repeat-associated small RNAs were observed in Hela cells. By using in situ hybridization, piR-49322 was localized in the nucleolus and around the periphery of nuclear membrane in Hela cells. Following the overexpression of HILI, the retrotransposon elements LINE1 was significantly repressed, while LINE1-associated small RNAs decreased in abundance. The present study demonstrated that HILI along with piRNAs plays a role in LINE1 suppression in Hela cancer cell line.

Comparison of Glutathione S-transferase-${\pi}$ Content in Drug-resistant and -sensitive Cancer Cells

  • Hong, Soon-Duck;Lee, Sang-Han
    • Journal of Life Science
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    • v.9 no.1
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    • pp.40-44
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    • 1999
  • Glutathione S-transferase (GST) is a multifunctional protein that catalyzes the catalyzes the conjugation of glutathione with electrophilic compounds. It exists in a variety of isoenzy-matic froms with a wide range of substrate specificity and plays a pivotal role in detoxification of various drugs. In order to elucidate the GST-${\pi}$'s involvement of multidrug resistance (MDR) in drug-resistant tumor cell lines, we determined GST-${\pi}$ content by "1 step sandwich method". Consequently, adriamycin resistant cells of MCF-7 (MCF-7/ADM) have 7-fold increase of GST-${\pi}$ content than that of MCF-7 cells, while its {TEX}$IC_{50}${/TEX} was 116-fold greater than parent cell line. By northrn blotting, we compared whether MCF-7/ADM cells express GST-${\pi}$ mRNA. The GST-${\pi}$ mRNA expression in these cells was not inducible, but constitutive when treated for 24 h with a concentration of 0, 20, 200, and 2000 nM of adriamycin, respectively. Taken together, these results suggest that GST-${\pi}$ may not be directly associated with multidrug resistance in these human cancer cell lines.ell lines.

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