Publications by authors named "Eri Hasegawa"

16 Publications

  • Page 1 of 1

Drosophila miR-87 promotes dendrite regeneration by targeting the transcriptional repressor Tramtrack69.

PLoS Genet 2020 08 7;16(8):e1008942. Epub 2020 Aug 7.

Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

To remodel functional neuronal connectivity, neurons often alter dendrite arbors through elimination and subsequent regeneration of dendritic branches. However, the intrinsic mechanisms underlying this developmentally programmed dendrite regeneration and whether it shares common machinery with injury-induced regeneration remain largely unknown. Drosophila class IV dendrite arborization (C4da) sensory neurons regenerate adult-specific dendrites after eliminating larval dendrites during metamorphosis. Here we show that the microRNA miR-87 is a critical regulator of dendrite regeneration in Drosophila. miR-87 knockout impairs dendrite regeneration after developmentally-programmed pruning, whereas miR-87 overexpression in C4da neurons leads to precocious initiation of dendrite regeneration. Genetic analyses indicate that the transcriptional repressor Tramtrack69 (Ttk69) is a functional target for miR-87-mediated repression as ttk69 expression is increased in miR-87 knockout neurons and reducing ttk69 expression restores dendrite regeneration to mutants lacking miR-87 function. We further show that miR-87 is required for dendrite regeneration after acute injury in the larval stage, providing a mechanistic link between developmentally programmed and injury-induced dendrite regeneration. These findings thus indicate that miR-87 promotes dendrite regrowth during regeneration at least in part through suppressing Ttk69 in Drosophila sensory neurons and suggest that developmental and injury-induced dendrite regeneration share a common intrinsic mechanism to reactivate dendrite growth.
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http://dx.doi.org/10.1371/journal.pgen.1008942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7439810PMC
August 2020

Neural Circuitry that Evokes Escape Behavior upon Activation of Nociceptive Sensory Neurons in Drosophila Larvae.

Curr Biol 2017 Aug 10;27(16):2499-2504.e3. Epub 2017 Aug 10.

Department of Biological Sciences, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address:

Noxious stimuli trigger a stereotyped escape response in animals. In Drosophila larvae, class IV dendrite arborization (C4 da) sensory neurons in the peripheral nervous system are responsible for perception of multiple nociceptive modalities, including noxious heat and harsh mechanical stimulation, through distinct receptors [1-9]. Silencing or ablation of C4 da neurons largely eliminates larval responses to noxious stimuli [10-12], whereas optogenetic activation of C4 da neurons is sufficient to provoke corkscrew-like rolling behavior similar to what is observed when larvae receive noxious stimuli, such as high temperature or harsh mechanical stimulation [10-12]. The receptors and the regulatory mechanisms for C4 da activation in response to a variety of noxious stimuli have been well studied [13-23], yet how C4 da activation triggers the escape behavior in the circuit level is still incompletely understood. Here we identify segmentally arrayed local interneurons (medial clusters of C4 da second-order interneurons [mCSIs]) in the ventral nerve cord that are necessary and sufficient to trigger rolling behavior. GFP reconstitution across synaptic partners (GRASP) analysis indicates that C4 da axons form synapses with mCSI dendrites. Optogenetic activation of mCSIs induces the rolling behavior, whereas silencing mCSIs reduces the probability of rolling behavior upon C4 da activation. Further anatomical and functional studies suggest that the C4 da-mCSI nociceptive circuit evokes rolling behavior at least in part through segmental nerve a (SNa) motor neurons. Our findings thus uncover a local circuit that promotes escape behavior upon noxious stimuli in Drosophila larvae and provide mechanistic insights into how noxious stimuli are transduced into the stereotyped escape behavior in the circuit level.
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http://dx.doi.org/10.1016/j.cub.2017.06.068DOI Listing
August 2017

Insights into the phylogeny of Northern Hemisphere Armillaria: Neighbor-net and Bayesian analyses of translation elongation factor 1-α gene sequences.

Mycologia 2017 6;109(1):75-91. Epub 2017 Feb 6.

y Department of Forestry, Environment and Systems , Kookmin University , Seoul 02707 , Republic of Korea.

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence-based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine phylogenetic relationships of newly determined and existing tef1 sequences derived from diverse Armillaria species from across the Northern Hemisphere, with Southern Hemisphere Armillaria species included for reference. Based on the Bayesian analysis of tef1 sequences, Armillaria species from the Northern Hemisphere are generally contained within the following four superclades, which are named according to the specific epithet of the most frequently cited species within the superclade: (i) Socialis/Tabescens (exannulate) superclade including Eurasian A. ectypa, North American A. socialis (A. tabescens), and Eurasian A. socialis (A. tabescens) clades; (ii) Mellea superclade including undescribed annulate North American Armillaria sp. (Mexico) and four separate clades of A. mellea (Europe and Iran, eastern Asia, and two groups from North America); (iii) Gallica superclade including Armillaria Nag E (Japan), multiple clades of A. gallica (Asia and Europe), A. calvescens (eastern North America), A. cepistipes (North America), A. altimontana (western USA), A. nabsnona (North America and Japan), and at least two A. gallica clades (North America); and (iv) Solidipes/Ostoyae superclade including two A. solidipes/ostoyae clades (North America), A. gemina (eastern USA), A. solidipes/ostoyae (Eurasia), A. cepistipes (Europe and Japan), A. sinapina (North America and Japan), and A. borealis (Eurasia) clade 2. Of note is that A. borealis (Eurasia) clade 1 appears basal to the Solidipes/Ostoyae and Gallica superclades. The Neighbor-net analysis showed similar phylogenetic relationships. This study further demonstrates the utility of tef1 for global phylogenetic studies of Armillaria species and provides critical insights into multiple taxonomic issues that warrant further study.
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http://dx.doi.org/10.1080/00275514.2017.1286572DOI Listing
May 2018

Identification of excitatory premotor interneurons which regulate local muscle contraction during Drosophila larval locomotion.

Sci Rep 2016 07 29;6:30806. Epub 2016 Jul 29.

Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan.

We use Drosophila larval locomotion as a model to elucidate the working principles of motor circuits. Larval locomotion is generated by rhythmic and sequential contractions of body-wall muscles from the posterior to anterior segments, which in turn are regulated by motor neurons present in the corresponding neuromeres. Motor neurons are known to receive both excitatory and inhibitory inputs, combined action of which likely regulates patterned motor activity during locomotion. Although recent studies identified candidate inhibitory premotor interneurons, the identity of premotor interneurons that provide excitatory drive to motor neurons during locomotion remains unknown. In this study, we searched for and identified two putative excitatory premotor interneurons in this system, termed CLI1 and CLI2 (cholinergic lateral interneuron 1 and 2). These neurons were segmentally arrayed and activated sequentially from the posterior to anterior segments during peristalsis. Consistent with their being excitatory premotor interneurons, the CLIs formed GRASP- and ChAT-positive putative synapses with motoneurons and were active just prior to motoneuronal firing in each segment. Moreover, local activation of CLI1s induced contraction of muscles in the corresponding body segments. Taken together, our results suggest that the CLIs directly activate motoneurons sequentially along the segments during larval locomotion.
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http://dx.doi.org/10.1038/srep30806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4965782PMC
July 2016

Formation of Neuronal Circuits by Interactions between Neuronal Populations Derived from Different Origins in the Drosophila Visual Center.

Cell Rep 2016 Apr 7;15(3):499-509. Epub 2016 Apr 7.

Brain/Liver Interface Medicine Research Center, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan; Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan; Laboratory of Developmental Neurobiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan; CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan. Electronic address:

A wide variety of neurons, including populations derived from different origins, are precisely arranged and correctly connected with their partner to establish a functional neural circuit during brain development. The molecular mechanisms that orchestrate the production and arrangement of these neurons have been obscure. Here, we demonstrate that cell-cell interactions play an important role in establishing the arrangement of neurons of different origins in the Drosophila visual center. Specific types of neurons born outside the medulla primordium migrate tangentially into the developing medulla cortex. During their tangential migration, these neurons express the repellent ligand Slit, and the two layers that the neurons intercalate between express the receptors Robo2 and Robo3. Genetic analysis suggests that Slit-Robo signaling may control the positioning of the layer cells or their processes to form a path for migration. Our results suggest that conserved axon guidance signaling is involved in the interactions between neurons of different origins during brain development.
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http://dx.doi.org/10.1016/j.celrep.2016.03.056DOI Listing
April 2016

Brain-specific-homeobox is required for the specification of neuronal types in the Drosophila optic lobe.

Dev Biol 2013 May 27;377(1):90-9. Epub 2013 Feb 27.

Lab of Developmental Neurobiology, Brain/Liver Interface Medicine Research Center, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi Kanazawa-shi, Ishikawa 920-8641, Japan.

The Drosophila optic lobe comprises a wide variety of neurons forming laminar and columnar structures similar to the mammalian brain. The Drosophila optic lobe may provide an excellent model to investigate various processes of brain development. However, it is poorly understood how neuronal specification is regulated in the optic lobe to form a complicated structure. Here we show that the Brain-specific-homeobox (Bsh) protein, which is expressed in the lamina and medulla ganglia, is involved in specifying neuronal identity. Bsh is expressed in L4 and L5 lamina neurons and in Mi1 medulla neurons. Analyses of loss-of-function and gain-of-function clones suggest that Bsh is required and largely sufficient for Mi1 specification in the medulla and L4 specification in the lamina. Additionally, Bsh is at least required for L5 specification. In the absence of Bsh, L5 is transformed into glial cells.
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http://dx.doi.org/10.1016/j.ydbio.2013.02.012DOI Listing
May 2013

Inhibitory effect of protopanaxatriol ginseng metabolite M4 on the production of corticosteroids in ACTH-stimulated bovine adrenal fasciculata cells.

Life Sci 2013 Apr 1;92(12):687-93. Epub 2013 Feb 1.

Department of Bio-Analytical Chemistry, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.

Aims: We investigated the pharmacological effects of saponins isolated from ginseng root and their metabolites, which occur by hydrolysis of the sugar moieties connecting the aglycone of saponins in the digestive tract, on the production of corticosteroids in bovine adrenal fasciculata cells in vitro.

Main Methods: The levels of corticosteroids produced from adrenal corticotropic hormone (ACTH)-stimulated bovine adrenal fasciculata cells were determined under the presence or absence of ginseng saponins (ginsenosides) and their metabolites using fluorometry, gas-chromatography-mass spectrometry, and sweeping-micellar electrokinetic capillary chromatography.

Key Findings: An end metabolite of the protopanaxatriol saponins in ginseng, 20(s)-protopanaxatriol (M4), strongly reduced ACTH-stimulated cortisol production. M4 significantly inhibited the production of cortisol induced by different stimuli, alamethicin, dibutyryl cyclic AMP, forskolin, and 22(R)-hydroxycholesterol, a membrane-permeable cholesterol. However, it did not affect the production of cortisol by either pregnenolone, a precursor of cortisol synthesis, or cyclic AMP. Furthermore, M4 significantly inhibited the production of pregnenolone, progesterone, deoxycorticosterone, cortisol, and corticosterone in a dose-dependent manner.

Significance: Results strongly suggest that protopanaxatriol saponins in ginseng are prodrugs metabolized in the digestive tract so that the end metabolite, M4, produces inhibitory activity of corticosteroid production in the adrenal fasciculata cells in vivo. The results also suggest that M4 inhibits the conversion from cholesterol to pregnenolone because the production of pregnenolone was reduced.
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http://dx.doi.org/10.1016/j.lfs.2013.01.023DOI Listing
April 2013

Effect of polyphenols on production of steroid hormones from human adrenocortical NCI-H295R cells.

Biol Pharm Bull 2013 ;36(2):228-37

Department of Bio-Analytical Chemistry, Niigata University of Pharmacy and Applied Life Sciences, 265–1 igashijima, Akiha-ku, Niigata 956–8603, Japan.

Modulating steroid hormone levels is a curative and preventive measure for Cushing's syndrome, aldosteronism, and various stress-triggered symptoms. Polyphenols have been reported to inhibit steroidogenic enzymes such as 3β-hydroxysteroid dehydrogenase (3β-HSD) and aromatase. However, evidence for their inhibitory effects is fragmentary because it has been determined in studies with small groups of steroid hormones. To investigate the effects of steroids on complete steroidogenic pathways, comprehensive analysis of steroid hormones is necessary. Here we cultured forskolin-stimulated NCI-H295R, a human adrenocortical carcinoma cell line, in the presence of a polyphenol and employed GC-MS to simultaneously determine the levels of nine steroid hormones (pregnenolone, progesterone, deoxycorticosterone, aldosterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone, and estradiol) in cell culture supernatant. We found that daidzein, genistein, apigenin, hesperetin, naringenin, and eriodictyol significantly reduced deoxycorticosterone and androstenedione levels (p<0.05), suggesting inhibition of 3β-HSD by these polyphenols. Apigenin was more potent than other polyphenols in increasing the levels of pregnenolone and 17α-hydroxyprogesterone, suggesting that it inhibits cytochrome P450 (CYP) 17 and CYP21, as well as 3β-HSD. Real-time reverse transcription polymerase chain reaction showed that apigenin significantly downregulated the expression levels of 3β-HSD, CYP17, and CYP21 mRNA (p<0.05). This is the first study to demonstrate the inhibitory effects of apigenin on CYP17 and CYP21.
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http://dx.doi.org/10.1248/bpb.b12-00627DOI Listing
August 2013

Oxysterol changes along with cholesterol and vitamin D changes in adult phenylketonuric patients diagnosed by newborn mass-screening.

Clin Chim Acta 2013 Feb 17;416:54-9. Epub 2012 Nov 17.

Department of Pediatrics, Takarazuka City Hospital, Takarazuka, Japan.

Background: Phenylketonuria (PKU) possibly leads to hypocholesterolemia and lowered vitamin D (VD) status. Metabolism of oxysterols linking with those of cholesterol and VD has never been examined in PKU.

Methods: Blood oxysterols along with blood phenylalanine, lipids and VD were examined for 33 PKU adults aged 21-38 years and 20 age-matched healthy controls.

Results: Total- and low-density cholesterols, and 25-hydroxy VD(3) were decreased significantly in the PKU group (cholesterols, 10% decrease; 25-hydroxy VD(3) 35% decrease vs. the control group). 24S-hydroxycholesterol (24S-OHC) eliminating brain cholesterol, and 27-OHC and 7α-hydroxycholesterol (7α-OHC) representing peripheral and hepatic cholesterol elimination, respectively, were significantly decreased in PKU group: 24S-OHC, 25% decrease, p<.01; 27-OHC and 7α-OHC, 35-40% decrease, p<.001. 7β-Hydroxycholesterol (7β-OHC) reflecting oxidative stress was increased significantly in PKU group (p<.05). 7α-OHC and 27-OHC levels in PKU group always showed similar values, regardless of other parameters while the 24S-OHC and 7β-OHC levels decreased and increased, respectively, showing significant correlations with phenylalanine level (p<.005). 27-OHC level showed a significant positive correlation with the 25-hydroxy VD(3) level in this group (p<.001).

Conclusion: Blood oxysterol changes predominate over blood cholesterol changes and influence on VD status in adult PKU patients.
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http://dx.doi.org/10.1016/j.cca.2012.10.011DOI Listing
February 2013

Prevalence of chronic kidney disease and blood pressure control status in elderly hypertensive patients.

Intern Med 2012 15;51(12):1473-8. Epub 2012 Jun 15.

Division of Hypertension, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Japan.

Objective: Hypertension guidelines recommend strict blood pressure (BP) control to less than 130/80 mmHg in patients complicated with chronic kidney disease (CKD). However, it is unclear whether this target BP level is applicable to the elderly hypertensive patients. The aim of this study was to assess the prevalence of CKD and BP control status in elderly hypertensive patients.

Methods: Subjects were 675 hypertensive patients (65.5 ± 11.7 years, 290 males and 385 females). Prevalence of CKD and BP control status were compared between elderly and young/middle-age patients.

Results: Average BP of elderly and young/middle-age patients were 134 ± 10/71 ± 9 mmHg and 131 ± 11/78 ± 9 mmHg, respectively. CKD was more prevalent in the elderly than in the young/middle-age patients (35.5% and 24.5%, respectively). The elderly patients with CKD were more likely to be males and older. They also required a greater number of antihypertensive drugs than those without CKD (2.4 ± 1.2 vs. 2.0 ± 1.1, p<0.01). Elderly patients without CKD who achieved a target BP of <140/90 mmHg were 73.2%. Similarly, 78.5% of the patients with CKD achieved BP of <140/90 mmHg, while those who achieved <130/80 mmHg were only 29.6%.

Conclusion: Our results suggest that CKD is frequently complicated in elderly hypertensive patients, and many of them failed to achieve strict BP goal in spite of the average use of 2.4 antihypertensive drugs.
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http://dx.doi.org/10.2169/internalmedicine.51.7285DOI Listing
November 2012

The effect of low-dose corticosteroids on short- and long-term renal outcome in patients with cholesterol crystal embolism.

Ren Fail 2011 ;33(3):298-306

Division of Nephrology and Clinical Research Institute, Department of Internal Medicine, National Kyushu Medical Center Hospital, Fukuoka, Japan.

Background: The effect of corticosteroids on renal cholesterol crystal embolism (CCE) remains uncertain. The aim of the present study was to elucidate the effect of steroid therapy on short- and long-term renal outcome in CCE patients.

Methods: Fifty-one patients diagnosed with renal CCE were included in this retrospective study. The patients were divided into two groups according to whether or not they had received steroid therapy (steroid therapy (+), n = 32; (-), n = 19). Corticosteroids were administered at an initial dose of 10-20 mg/day after CCE diagnosis. The values of the estimated glomerular filtration rate (eGFR) in the two groups were examined at CCE diagnosis, 4 weeks after diagnosis and the last follow-up. Additionally, the % change in eGFR at 4 weeks after diagnosis and % change per year in eGFR at the last follow-up were calculated for each patient.

Results: The median values of eGFR at diagnosis in patients with and without steroid therapy were 16.4 and 17.9 mL/min/1.73 m(2), respectively. The median % change in eGFR between diagnosis and 4 weeks after diagnosis was 24% in patients with steroid therapy and 5% in those without, and this difference was statistically significant. On the other hand, there was no significant difference between the two groups in the % change in eGFR per year between diagnosis and the last follow-up.

Conclusions: During the short period after CCE diagnosis, steroid therapy showed a good renal outcome in CCE patients. However, this treatment did not have a favorable effect on long-term renal outcome.
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http://dx.doi.org/10.3109/0886022X.2011.560403DOI Listing
July 2011

Concentric zones, cell migration and neuronal circuits in the Drosophila visual center.

Development 2011 Mar;138(5):983-93

Frontier Science Organization, Kanazawa University, 13-1 Takaramachi Kanazawa-shi, Ishikawa, Japan.

The Drosophila optic lobe comprises a wide variety of neurons, which form laminar neuropiles with columnar units and topographic projections from the retina. The Drosophila optic lobe shares many structural characteristics with mammalian visual systems. However, little is known about the developmental mechanisms that produce neuronal diversity and organize the circuits in the primary region of the optic lobe, the medulla. Here, we describe the key features of the developing medulla and report novel phenomena that could accelerate our understanding of the Drosophila visual system. The identities of medulla neurons are pre-determined in the larval medulla primordium, which is subdivided into concentric zones characterized by the expression of four transcription factors: Drifter, Runt, Homothorax and Brain-specific homeobox (Bsh). The expression pattern of these factors correlates with the order of neuron production. Once the concentric zones are specified, the distribution of medulla neurons changes rapidly. Each type of medulla neuron exhibits an extensive but defined pattern of migration during pupal development. The results of clonal analysis suggest homothorax is required to specify the neuronal type by regulating various targets including Bsh and cell-adhesion molecules such as N-cadherin, while drifter regulates a subset of morphological features of Drifter-positive neurons. Thus, genes that show the concentric zones may form a genetic hierarchy to establish neuronal circuits in the medulla.
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http://dx.doi.org/10.1242/dev.058370DOI Listing
March 2011

Clustering of cardiovascular risk factors and blood pressure control status in hypertensive patients.

Intern Med 2010 2;49(15):1483-7. Epub 2010 Aug 2.

Division of Hypertension, Clinical Research Institute, National Kyushu Medical Center, Fukuoka.

Objective: Hypertensive patients have multiple risk factors such as chronic kidney disease (CKD) and hyperuricemia in addition to components of metabolic syndrome. The morbidity of cardiovascular diseases is expected to increase synergistically by clustering of them. In the present study, we assessed the clustering of cardiovascular risk factors and blood pressure (BP) control status in hypertensive patients.

Methods And Patients: Subjects were 699 treated hypertensive patients (mean age: 65 +/- 12 years; males 297, females 402) who had been followed at National Kyushu Medical Center, Fukuoka, Japan. We assessed the status of BP control and the presence of comorbidity including obesity, diabetes mellitus (DM), dyslipidemia, CKD and hyperuricemia.

Results: Average BP level and the number of antihypertensive drugs were 133 +/- 11/74 +/- 10 mmHg and 2.0 +/- 1.1, respectively and the average number of cardiovascular risk factors was 1.5 +/- 1.1. No comorbid risk factors were found in 18.7% of the patients. On the other hand, 34.2%, 28.9% and 18.2% of the patients had one, two or more than three risk factors, respectively. There were no significant differences in BP among these groups, while patients with three or more risk factors needed a greater number of antihypertensive drugs than those with other groups. Patients with three or more risk factors group showed significantly higher body mass index, serum LDL cholesterol, triglyceride, plasma glucose and serum uric acid levels compared to those with other groups (p<0.05, respectively). They also showed significantly lower serum HDL cholesterol and estimated GFR levels compared to those in other groups (p<0.05, respectively).

Conclusion: These results suggest that the majority of the treated hypertensive patients are complicated with additional cardiovascular risk factors and the patients with clustering risk factors required a greater number of antihypertensive drugs. Integrative management of BP as well as comorbid risk factors should be encouraged.
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http://dx.doi.org/10.2169/internalmedicine.49.3406DOI Listing
May 2011

Sequence-based identification of Japanese Armillaria species using the elongation factor-1 alpha gene.

Mycologia 2010 Jul-Aug;102(4):898-910

Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyutaro-68, Momoyama, Fushimi, Kyoto 612-0855, Japan.

We analyzed the sequences of three DNA regions-the translation elongation factor-1 alpha (EF-1 alpha) gene and the internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of ribosomal DNA-to compare their accuracy in identifying species of Japanese Armillaria. We studied 49 isolates of eight Armillaria species, A. mellea, A. ostoyae, A. nabsnona, A. cepistipes, A. gallica, A. sinapina, A. tabescens and the biological species Nagasawa E (Nag. E). Phylogenetic analyses of the ITS and IGS data helped in identifying A. mellea, A. ostoyae, A. nabsnona, A. tabescens and Nag. E but could not be used to identify A. gallica, A. cepistipes and A. sinapina. Nevertheless our analysis showed that the EF-1 alpha gene was clearly different in the eight examined species. Restriction fragment length polymorphisms (RFLP) of the IGS-1 region could be used to distinguish most species, but the RFLP profiles of some isolates of A. cepistipes and A. sinapina were the same even with four different restriction enzymes. In conclusion, among the techniques examined in this study, analyzing the EF-1 alpha sequence was found to be the most suitable method for identifying different species of Japanese Armillaria.
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http://dx.doi.org/10.3852/09-238DOI Listing
August 2010

Neuroblast entry into quiescence is regulated intrinsically by the combined action of spatial Hox proteins and temporal identity factors.

Development 2008 Dec 23;135(23):3859-69. Epub 2008 Oct 23.

Center for Frontier Research, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.

Neural stem cell quiescence is an important feature in invertebrate and mammalian central nervous system development, yet little is known about the mechanisms regulating entry into quiescence, maintenance of cell fate during quiescence, and exit from quiescence. Drosophila neural stem cells (called neuroblasts) provide an excellent model system for investigating these issues. Drosophila neuroblasts enter quiescence at the end of embryogenesis and resume proliferation during larval stages; however, no single neuroblast lineage has been traced from embryo into larval stages. Here, we establish a model neuroblast lineage, NB3-3, which allows us to reproducibly observe lineage development from neuroblast formation in the embryo, through quiescence, to the resumption of proliferation in larval stages. Using this new model lineage, we show a continuous sequence of temporal changes in the neuroblast, defined by known and novel temporal identity factors, running from embryonic through larval stages, and that quiescence suspends but does not alter the order of neuroblast temporal gene expression. We further show that neuroblast entry into quiescence is regulated intrinsically by two independent controls: spatial control by the Hox proteins Antp and Abd-A, and temporal control by previously identified temporal transcription factors and the transcription co-factor Nab.
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http://dx.doi.org/10.1242/dev.025189DOI Listing
December 2008

C. elegans CPB-3 interacts with DAZ-1 and functions in multiple steps of germline development.

Dev Biol 2006 Jul 7;295(2):689-99. Epub 2006 Apr 7.

Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.

Cytoplasmic polyadenylation element-binding proteins (CPEBs) are well-conserved RNA-binding proteins, which regulate mRNA translation mainly through control of poly(A) elongation. Here, we show that CPB-3, one of the four CPEB homologs in C. elegans, positively regulates multiple aspects of oocyte production. CPB-3 protein was highly expressed in early meiotic regions of the hermaphrodite gonad. Worms deficient in cpb-3 were apparently impaired in germ cell proliferation and differentiation including sperm/oocyte switching and progression of female meiosis. We also show that cpb-3 is likely to promote the meiotic entry in parallel with gld-3, a component of one of the redundant but essential genetic pathways for the entry to and progression through meiosis. Taken together, CPEB appears to have a conserved role in the early phase of meiosis and in the sperm/oocyte specification, in addition to its reported function during meiotic progression.
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http://dx.doi.org/10.1016/j.ydbio.2006.04.002DOI Listing
July 2006
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