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GD2 expression is closely associated with neuronal differentiation of human umbilical cord blood-derived mesenchymal stem cells

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CELLULAR AND MOLECULAR LIFE SCIENCES 2010年第11期67卷 1845-1858页

作者： Jin, Hye Jin Nam, Hae Yun Bae, Yun Kyong Kim, Soo Yeon Im, I. Rang Oh, Wonil Yang, Yoon Sun Choi, Soo Jin Kim, Seong Who Univ Ulsan Coll Med Dept Biochem & Mol Biol Seoul 136736 South Korea Medipost Co Ltd Biomed Res Inst Seoul 136736 South Korea Mercersburg Acad Mercersburg PA 17236 USA

GD2 ganglioside has been identified as a key determinant of bone marrow-derived mesenchymal stem cells (BM-MSCs). Here, we characterized GD2 ganglioside expression and its implications in umbilical cord blood-derived MSCs (UCB-MSCs). Using immune-selection analysis, we showed that both GD2-positive and GD2-negative UCB-MSCs expressed general stem cell markers and possessed mesodermal lineage differentiation potential. Although the fraction of GD2-expressing cells was lower in UCB-MSC than in BM-MSC populations, inhibition of GD2 synthesis in UCB-MSCs suppressed neuronal differentiation and down-regulated basic helix-loop-helix (bHLH) transcription factors, which are involved in early stage neuronal differentiation. In addition, the levels of bHLH factors in neuronally induced UCB-MSCs were significantly higher in GD2-positive than GD2-negative cells. Our data demonstrate that GD2 ganglioside expression is associated with regulation of bHLH factors and identify neurogenic-capable UCB-MSCs, providing new insights into the potential clinical applications of MSC-based therapy.

关键词： Umbilical cord blood Mesenchymal stem cells Ganglioside GD2 Multi-lineage differentiation Neuronal differentiation basic helix-loop-helix

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Regional Expression of MTG Genes in the Developing Mouse Central Nervous System

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DEVELOPMENTAL DYNAMICS 2009年第8期238卷 2095-2102页

作者： Alishahi, Amin Koyano-Nakagawa, Naoko Nakagawa, Yasushi Univ Minnesota Sch Med Dept Neurosci Minneapolis MN 55455 USA Univ Minnesota Sch Med Stem Cell Inst Minneapolis MN 55455 USA

Myeloid translocation gene (MTG) proteins are transcriptional repressors that are highly conserved across species. We studied the expression of three members of this gene family, MTGR1, MTG8, and MTG16 in developing mouse central nervous system by in situ hybridization. All of these genes are detected as early as embryonic day 11.5. Because these genes are known to be induced by proneural genes during neurogenesis, we analyzed the expression of MTG genes in relation to two proneural genes, Neurog2 (also known as Ngn2 or Neurogenin 2) and Ascl1 (also known as Mash1). While MTGR1 are generally expressed in regions that also express Neurog2, MTG8 and MTG16 expression is associated more tightly with that of Ascl1-expressing neural progenitor cells. These results suggest the possibility that expression of MTG genes is differentially controlled by specific proneural genes during neurogenesis. Developmental Dynamics 238: 2095-2102, 2009. (C) 2009 Wiley-Liss, Inc.

关键词： MTG8 MTG16 MTGR1 CBFA2T1 CBFA2T2 CBFA2T3 ETO ETO-2 ETO-R EHT Neurog2 Ngn2 Neurogenin Ascl1 Mash1 achaete-scute homolog neurogenesis differentiation neuronal progenitor spinal cord telencephalon diencephalon thalamus retina central nervous system CNS lineage tracing basic helix-loop-helix bHLH transcription factor transcriptional repressor histone deacetylase HDAC N-CoR Sin3A AML acute myeloid leukemia Nvy nervy

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Tissue-specific and ubiquitous basic helix-loop-helix transcription factors in human placental trophoblasts

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PLACENTA 2005年第7期26卷 527-539页

作者： Meinhardt, G Husslein, P Knöfler, M Med Univ Vienna Dept Obstet & Gynecol AKH A-1090 Vienna Austria

Tissue-specific class B basic helix- loop-helix (bHLH) transcription factors, dimerising with ubiquitously produced class A bHLH proteins, play a major role in murine trophoblast development. Here, we investigated expression patterns of class A and B bHLH factors in the human placenta and different trophoblast culture systems. Semi-quantitative RT-PCR and RNase protection assay revealed expression of the tissue-restricted factors Hash-2, I-mfa and Stra13 in placentae of early and late pregnancy, in purified villous trophoblasts as well as in invasive trophoblasts isolated from first trimester villous explant cultures. Accordingly I RNA in situ hvbridisation localised Hash-2, I-mfa and Stra13 to the trophoblast epithelium, cell columns and extravillous trophoblasts invading maternal decidua. Villous stromal cells in situ and cultivated placental fibroblasts also produced I-mfa and Stra13 but failed to express Hash-2. The widely expressed class A proteins, E12/E47 were absent from all placental cell types while ITF-2 was restricted to placental stromal cells of early and late gestation. In contrast, HEB was identified in all trophoblast cell types using RT-PCR, Western blotting and immunohistochemistry. The negative HLH-regulators Id-1 and Id-2 lacking the DNA-binding domain, were detected in villous stromal cells and different cytotrophoblast subtypes but were absent from the syncytium. The data suggest that a complex interplay of activators (Hash-2, HEB) and repressors (Stral3, I-mfa) could be involved in extravillous trophoblast differentiation whereas downregulation of Id proteins could play a role in syncytialisation.. (c) 2004 Elsevier Ltd. All rights reserved.

关键词： human placenta trophoblast transcription factor basic helix-loop-helix

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Expression of the basic helix-loop-factor Olig2 in the developing retina: Olig2 as a new marker for retinal progenitors and late-born cells

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GENE EXPRESSION PATTERNS 2007年第1-2期7卷 57-65页

作者： Shibasaki, Koi Takebayashi, Hirohide Ikenaka, Kazuhiro Feng, Liang Gan, Lin Univ Rochester Sch Med Ctr Aging & Dev Biol Rochester NY 14642 USA Natl Inst Nat Sci Okazaki Inst Integrat Biosci Sect Cell Signaling Okazaki Aichi 4448787 Japan Natl Inst Physiol Sci Div Neurobiol & Bioinformat Okazaki Aichi 4448787 Japan

In this study, we examined the spatiotemporal expression patterns of Olig2, a basic helix-loop-helix transcription factor, in the developing mouse retina. Expression of Olig2 was initially detected on embryonic day 12.5 (E12.5). The majority of Olig2-positive cells were identified as retinal progenitor cells throughout embryogenesis. During later embryonic stages, the number of Olig2-positive retinal progenitor cells increased, and Olig2-positive cells were confined only to the neuroblast layer (NBL). Olig2 expression was not observed in the ganglion cell layer (GCL) nor in the inner nuclear layer (INL) that contain the differentiated retinal cell types, indicating that Olig2 is not expressed in differentiated cells in prenatal retina. In later postnatal stages, Olig2 expression was retained in mature neurons and glial cells, namely retinal ganglion cells (RGCs), amacrine cells (ACs), horizontal cells, bipolar cells and Muller glial cells. Thus, Olig2 is an marker both for retinal progenitor cells during embryonic stages, and also for differentiated retinal subpopulations within the GCL and INL during postnatal stages. (c) 2006 Elsevier B.V. All rights reserved.

关键词： retina neurogenesis basic helix-loop-helix transcription factor progenitor Olig2 differentiation cell specification homeobox development

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Novel Nuclear Protein ALC-INTERACTING PROTEIN1 is Expressed in Vascular and Mesocarp Cells in Arabidopsis

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Journal of Integrative Plant Biology 2008年第7期50卷 918-927页

作者： Fang Wang Dong-Qiao Shi Jie Liu Wei-Cai Yang Key Laboratory of Molecular and Developmental Biology National Centre for Plant Gene Research Institute of Genetics and Developmental Biology the Chinese Academy of Sciences Beijing 100101 China Graduate University the Chinese Academy of Sciences Beijing 100039 China

Pod shattering is an agronomical trait that is a result of the coordinated action of cell differentiation and separation. In Arabidopsis, pod shattering is controlled by a complex genetic network in which ALCATRAZ （ALC）, a member of the basic helix-loop-helix family, is critical for cell separation during fruit dehiscence. Herein, we report the identification of ALC-INTERACTING PROTEIN1 （ACI1） via the yeast two-hybrid screen. ACll encodes a nuclear protein with a lysine-rich domain and a C-terminal serine-rich domain. ACI1 is mainly expressed in the vascular system throughout the plant and mesocarp of the valve in siliques. Our data showed that ACI1 interacts strongly with the N-terminal portion of ALC in yeast cells and in plant cells in the nucleus as demonstrated by bimolecular fluorescence complementaUon assay. Both ACI1 and ALC share an overlapping expression pattern, suggesting that they likely function together in planta. However, no detectable phenotype was found in plants with reduced ACll expression by RNA interference technology, suggesting that ACll may be redundant. Taken together, these data indicate that ALC may interact with ACI1 and its homologs to control cell separation during fruit dehiscence in Arabidopsis.

关键词： ALC-INTERACTING PROTEIN1 ALCATRAZ Arabidopsis basic helix-loop-helix nuclear protein transcription factor.

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AhR/Arnt:XRE interaction:: Turning false negatives into true positives in the modified yeast one-hybrid assay

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ANALYTICAL BIOCHEMISTRY 2008年第2期382卷 101-106页

作者： Chen, Gang Shin, Jumi A. Univ Toronto Dept Chem Mississauga ON L5L 1C6 Canada Univ Toronto Inst Biomat & Biomed Engn Toronto ON M5S 3G9 Canada

Given the frequent occurrence of false negatives in yeast genetic assays, it is both interesting and practical to address the possible mechanisms of false negatives and, more important, to turn false negatives into true positives. We recently developed a modified yeast one-hybrid system (MY1H) useful for investigation of simultaneous protein-protein and protein:DNA interactions in vivo. We coexpressed the basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) domains of aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt)-namely NAhR and NArnt, respectively-which are known to form heterodimers and bind the cognate xenobiotic response element (XRE) sequence both in vitro and in vivo, as a positive control in the study of XRE-binding proteins in the MY1H system. However, we observed negative results, that is, no positive signal detected from binding of the NAhR/NArnt heterodimer and XRE site. We demonstrate that by increasing the copy number of XRE sites integrated into the yeast genome and using double GAL4 activation domains, the NAhR/NArnt heterodimer forms and specifically binds the cognate XRE sequence, an interaction that is now clearly detectable in the MY1H system. This methodology may be helpful in troubleshooting and correcting false negatives that arise from unproductive transcription in yeast genetic assays. (C) 2008 Elsevier Inc. All Fights reserved.

关键词： aryl hydrocarbon receptor basic helix-loop-helix xenobiotic response element protein-protein interaction protein : DNA interaction yeast one-hybrid

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Transcriptional cascade from Math1 to Mbh1 and Mbh2 is required for cerebellar granule cell differentiation

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DEVELOPMENTAL BIOLOGY 2008年第2期322卷 345-354页

作者： Kawauchi, Daisuke Saito, Tetsuichiro Chiba Univ Grad Sch Med Dept Dev Biol Chuo Ku Chiba 2608670 Japan

Cerebellar granule cells (CGCs) are the most abundant neuronal type in the mammalian brain, and their differentiation is regulated by the basic helix-loop-helix gene, math1. However, little is known about downstream genes of Math1 and their functions in the cerebellum. To investigate them, we have here established an electroporation-based in vivo gene transfer method in the developing mouse cerebellum. Misexpression of Math1 ectopically induced expression of Bar-class homeobox genes, Mbh1 and Mbh2, which are expressed by CGCs. Conversely, their expression was repressed in CGCs by knockdown of math1. These findings, taken together with chromatin immunoprecipitation assays, suggest that math1 directly regulates the Mbh genes in CGCs. Furthermore, a dominant-negative form of the Mbh proteins disrupted proper formation of the external granule layer and differentiation of CGCs, whereas misexpression of the Mbh genes ectopically induced expression of a CGC marker in nonneuronal cells, indicating that the Mbh proteins are required for the differentiation of CGCs. (C) 2008 Elsevier Inc. All rights reserved.

关键词： Cerebellar granule cells Purkinje cells basic helix-loop-helix Homeobox Math1 Ptf1a Mbh1 Mbh2 In vivo electroporation

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Molecular mechanism of transforming growth factor-β-mediated inhibition of growth arrest and differentiation in a myoblast cell line

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DEVELOPMENT GROWTH & DIFFERENTIATION 2008年第2期50卷 121-130页

作者： Murakami, Masanori Ohkuma, Mizue Nakamura, Masataka Tokyo Med & Dent Univ Human Gene Sci Ctr Tokyo 1138510 Japan

Transforming growth factor-beta (TGF-beta) has been demonstrated to inhibit myogenesis in myoblasts. Here we report that transcriptional upregulation of p21(WAF1/Cip1) and muscle creatinine kinase (MCK) genes in C2C12 cells, which are associated with growth arrest at the G1 phase and representative cell-lineage-specific expression during myogenesis, was inhibited by TGF-beta treatment. C2C12 cells expressed TWIST2, but not TWIST1, which was downregulated in myogenic differentiation in response to low-serum cultures. We further found that TGF-beta prevented differentiation-associated downregulation of TWIST2 transcription, resulting in maintaining TWIST2 mRNA expression as high as that in growing C2C12 cells. Ectopic TWIST2 suppressed the p21 and MCK promoters activated by the exogenous addition of E2A and MyoD and this inhibitory effect of TWIST2 was cancelled by the introduction of short hairpin RNA (shRNA) against TWIST2. On the other hand, TWIST2 shRNA failed to recover endogenous promoter activities from TGF-beta-mediated repression. The results clearly indicate that TGF-beta inhibits G1 arrest and maintains TWIST2 expression in C2C12 cells. Our data however suggest that the TGF-beta signaling pathway may not involve TWIST2 to inhibit p21 and MCK expression.

关键词： basic helix-loop-helix myogenesis p21(WAF1/Cip1) transforming growth factor-beta TWIST2

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Light-induced phosphorylation and degradation of the negative regulator PHYTOCHROME-INTERACTING FACTOR1 from Arabidopsis depend upon its direct physical interactions with photoactivated phytochromes

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PLANT CELL 2008年第6期20卷 1586-1602页

作者： Shen, Hui Zhu, Ling Castillon, Alicia Majee, Manoj Downie, Bruce Huq, Enamul Univ Texas Austin Sect Mol Cell & Dev Biol Austin TX 78712 USA Univ Texas Austin Inst Cellular & Mol Biol Austin TX 78712 USA Univ Kentucky Dept Hort Lexington KY 40546 USA Univ Kentucky Seed Biol Grp Lexington KY 40546 USA

The phytochrome (phy) family of photoreceptors regulates changes in gene expression in response to red/far-red light signals in part by physically interacting with constitutively nucleus-localized phy-interacting basic helix-loop-helix transcription factors (PIFs). Here, we show that PIF1, the member with the highest affinity for phys, is strongly sensitive to the quality and quantity of light. phyA plays a dominant role in regulating the degradation of PIF1 following initial light exposure, while phyB and phyD and possibly other phys also influence PIF1 degradation after prolonged illumination. PIF1 is rapidly phosphorylated and ubiquitinated under red and far-red light before being degraded with a half-life of;1 to 2 min under red light. Although PIF1 interacts with phyB through a conserved active phyB binding motif, it interacts with phyA through a novel active phyA binding motif. phy interaction is necessary but not sufficient for the light-induced phosphorylation and degradation of PIF1. Domain-mapping studies reveal that the phy interaction, light-induced degradation, and transcriptional activation domains are located at the N-terminal 150-amino acid region of PIF1. Unlike PIF3, PIF1 does not interact with the two halves of either phyA or phyB separately. Moreover, overexpression of a light-stable truncated form of PIF1 causes constitutively photomorphogenic phenotypes in the dark. Taken together, these data suggest that removal of the negative regulators (e. g., PIFs) by light-induced proteolytic degradation might be sufficient to promote photomorphogenesis.

关键词： .constitutively regulator negative phytochromes PhyA basic helix-loop-helix light-induced phyB light signals PIFs photoactivated Direct Physical Phosphorylation and Degradation phytochrome-interacting

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Synthesis of nicotianamine and deoxymugineic acid is regulated by OsIRO2 in Zn excess rice plants

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SOIL SCIENCE AND PLANT NUTRITION 2008年第3期54卷 417-423页

作者： Ishimaru, Yasuhiro Suzuki, Motofumi Ogo, Yuko Takahashi, Michiko Nakanishi, Hiromi Mori, Satoshi Nishizawa, Naoko K. Univ Tokyo Dept Global Agr Sci Grad Sch Agr & Life Sci Bunkyo Ku Tokyo 1138657 Japan Univ Tokyo Dept Appl Biol Chem Grad Sch Agr & Life Sci Tokyo 1138657 Japan

Zinc (Zn) excess has significant toxicity to biological systems through metal-based cytotoxic reactions. Nicotianamine (NA) and deoxymugineic acid (DMA) are low-molecular-weight, high-affinity transition metal chelators. Studies have shown that NA may have a role in the tolerance of excess Zn. We show that a gene coding the iron (Fe)-regulated DNA-binding transcription factor (OsIRO2) and the downstream genes of OsIRO2, such as NA synthase, DMA synthase and the DMA-Fe3+ transporter, were induced in rice roots by excess Zn. Consistent with the expression of these genes, the amounts of endogenous NA, endogenous DMA and DMA secretion increased in the excess Zn roots. Although the Fe concentration in the excess Zn roots was much higher than that in the control, rice ferritin gene, OsFer1, was downregulated in Zn excess roots. OsIRT1, which is upregulated by Fe deficiency, was not induced in Zn excess roots, suggesting that OsIRO2 may not be induced simply by the Fe deficiency caused by excess Zn. The data indicate that the induction of OsIRO2 by excess Zn is responsible for the production of NA and DMA, which may play a role in maintaining cellular Zn availability.

关键词： basic helix-loop-helix deoxymugineic acid nicotianamine transcriptional factor zinc excess

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