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Notch-induced E2A ubiquitination and degradation are controlled by MAP kinase activities

EMBO JOURNAL 2003年第21期22卷 5780-5792页

作者： Nie, L Xu, M Vladimirova, A Sun, XH Oklahoma Med Res Fdn Immunobiol & Canc Program Oklahoma City OK 73104 USA

Notch signals are important for lymphocyte development but downstream events that follow Notch signaling are not well understood. Here, we report that signaling through Notch modulates the turnover of E2A proteins including E12 and E47, which are basic helix-loop-helix proteins crucial for B and T lymphocyte development. Notch-induced degradation requires phosphorylation of E47 by p42/p44 MAP kinases. Expression of the intracellular domain of Notch1 (N1-IC) enhances the association of E47 with the SCFSkp2 E3 ubiquitin ligase and ubiquitination of E47, followed by proteasome-mediated degradation. Furthermore, N1-IC induces E2A degradation in B and T cells in the presence of activated MAP kinases. Activation of endogenous Notch receptors by treatment of splenocytes with anti-IgM or anti-CD3 plus anti-CD28 also leads to E2A degradation, which is blocked by the inhibitors of Notch activation or proteasome function. Notch-induced E2A degradation depends on the function of its downstream effector, RBP-Jkappa, probably to activate target genes involved in the ubiquitination of E2A proteins. Thus we propose that Notch regulates lymphocyte differentiation by controlling E2A protein turnover.

关键词： basic helix-loop-helix cell fate development Notch ubiquitination

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Dynamic expression of basic helix-loop-helix Olig family members: implication of Olig2 in neuron and oligodendrocyte differentiation and identification of a new member, Olig3

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MECHANISMS OF DEVELOPMENT 2000年第1-2期99卷 143-148页

作者： Takebayashi, H Yoshida, S Sugimori, M Kosako, H Kominami, R Nakafuku, M Nabeshima, Y Kyoto Univ Grad Sch Med Dept Pathol & Tumor Biol Sakyo Ku Kyoto 6068501 Japan Univ Tokyo Grad Sch Med Dept Neurobiol Bunkyo Ku Tokyo 1130033 Japan Niigata Univ Sch Med Biochem Lab 1 Niigata 9518122 Japan

basic helix-loop-helix (bHLH) transcription factors have been shown to be essential for specification of various cell types. Here, we describe a novel bHLH family consisting of three members, two of which (Olig1, Olig2) are expressed in a nervous tissue-specific manner, whereas the third, Olig3 is found mainly in non-neural tissues. Olig1 and Olig2, which recently have been implicated in oligodendrogenesis, are expressed in the region of the ventral ventricular zone of late embryonic spinal cord where oligodendrocyte progenitors appear. In the embryonic brain, the Olig2 expression domain is broader than that of Olig1 and does not overlap with an oligodendrocyte progenitor marker, CNP. Furthermore, Olig2 is expressed in most cells in the ventral half of the early embryonic spinal cord, which do not yet express an early neuronal marker TuJ1. These results indicate that Olig2 expression is not limited to the oligodendrocyte lineage but includes immature neuronal progenitors and multipotential neuron/glia progenitors as well as embryonic olfactory neurons. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.

关键词： basic helix-loop-helix transcription factor Olig family Olig1 Olig2 Olig3 genomic mapping Mash1 TuJ1 differentiation Oligodendrocyte progenitor Oligodendrogenesis motor neuron olfactory neuron neurogenesis ganglionic eminence spinal cord mouse rat

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The cellular Pax-Hox-helix connection

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BIOCHIMICA ET BIOPHYSICA ACTA-GENE STRUCTURE AND EXPRESSION 2003年第1-3期1629卷 1-7页

作者： Westerman, BA Murre, C Oudejans, CBM Vrije Univ Amsterdam Med Ctr Mol Biol Lab Dept Clin Chem NL-1081 HV Amsterdam Netherlands Univ Calif San Diego Dept Biol La Jolla CA 92093 USA

basic helix-loop-helix (bHLH) transcription factors are important regulators of lineage determination during embryogenesis. Initial experiments in Drosophila showed that early neural selection and specification are dependent on atonal (ato) and members of the achaete-scute complex (as-c). In mammals, transcription factors homologous to as-c and ato are causally involved during development of organs throughout the body. Development of subsets of lineages in intestine, stomach, pancreas, lung, thyroid and placenta have been shown to be regulated by members of the as-c and ato families. These functional studies show that an individual bHLH transcription factor can regulate multiple developmental processes throughout the mammalian body, which implicates that extant as-c and ato transcription factors play a distinct function dependent on their cellular context. Based on the synergistic activation of the insulin, POMC and Pax4 promotors by bHLH and homeobox (Hex) protein complexes, we hypothesize that the underlying cellular function-modulating factors include members of the Hox and paired box (Pax) multigene families. These examples indicate that unique combinations of bHLH and Hex proteins, mediated by protein-protein interactions, might be responsible for activating cell-specific sets of target genes. (C) 2003 Elsevier B.V All rights reserved.

关键词： basic helix-loop-helix homeobox transcription factor mammal protein-protein interaction

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A New Twist on Twist Modulation of the NF-κB Pathway

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CELL CYCLE 2003年第2期2卷 76-78页

作者： Sosic, Drazen Olson, Eric N. Univ Texas SW Med Ctr Dallas Dept Mol Biol 6000 Harry Hines Blvd Dallas TX 75390 USA

No abstract available.

关键词： Cachexia Cytokines basic helix-loop-helix NF-kappa B Mesoderm

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MyoR is expressed in nonmyogenic cells and can inhibit their differentiation

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EXPERIMENTAL CELL RESEARCH 2003年第1期289卷 162-173页

作者： Yu, LM Mikloucich, J Sangster, N Perez, A McCormick, PJ Univ Albany Ctr Funct Genom Rensselaer NY 12144 USA SUNY Albany Dept Biol Sci Albany NY 12222 USA

The development of skeletal muscle in mammals is promoted by the muscle-specific basic helix-loop-helix transcription factors of the MyoD family. Evidence also suggests that there are basic helix-loop-helix proteins that specifically inhibit skeletal myogenesis, including Mtwist, Mist1, and the most recently described, MyoR. It has been suggested that MyoR expression is limited to the precursors of the skeletal muscle lineage and acts as a transcriptional repressor of the muscle differentiation program. However, our results demonstrate that MyoR is expressed in several different, nonmuscle adult tissues. Furthermore, MyoR is expressed in the embryonic ectoderm of blastocyst stage mouse embryos, well before skeletal muscle specification and even before delineation of the mesodermal germ layer. Using embryonic ectoderm analogous stem cells, we demonstrate that in these nonmuscle cells, as in skeletal muscle precursor cells, expression of MyoR is inversely correlated with the extent of cellular differentiation as induced by retinoic acid. Our preliminary results indicate that overexpression of exogenous MyoR inhibits retinoic-acid-induced differentiation in EC cells and is lethal to early mouse embryos. Our results suggest a much broader role for MyoR in the repression and/or determination of embryonic cell differentiation. (C) 2003 Elsevier Science (USA). All rights reserved.

关键词： MyoR myogenesis basic helix-loop-helix musculin retinoic acid embryonal carcinoma trichostatin aA

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Novel transcriptional potentiation of BETA2/NeuroD on the secretin gene promoter by the DNA-binding protein Finb/RREB-1

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MOLECULAR AND CELLULAR BIOLOGY 2003年第1期23卷 259-271页

作者： Ray, SK Nishitani, J Petry, MW Fessing, MY Leiter, AB Tufts Univ New England Med Ctr Sch Med Div Gastroenterol 218GRASP Digest Dis Ctr Boston MA 02111 USA

The basic helix-loop-helix protein BETA2/NeuroD activates transcription of the secretin gene and is essential for terminal differentiation of secretin-producing enteroendocrine cells. However, in heterodimeric complexes with its partner basic helix-loop-helix proteins, BETA2 does not appear to be a strong activator of transcription by itself. Mutational analysis of a proximal enhancer in the secretin gene identified several cis-acting elements in addition to the E-box binding site for BETA2. We identified by expression cloning the zinc finger protein RREB-1, also known to exist as a longer form, Finb, as the protein binding to one of the mutationally sensitive elements. Finb/RREB-1 lacks an intrinsic activation domain and by itself did not activate secretin gene transcription. Here we show that Finb/RREB-1 can associate with BETA2 to enhance its transcription-activating function. Both DNA binding and physical interaction of Finb/RREB-1 with BETA2 are required to potentiate transcription. Thus, Finb/RREB-1 does not function as a classical activator of transcription that recruits an activation domain to a DNA-protein complex. Finb/RREB-1 may be distinguished from coactivators, which increase transcription without sequence- specific DNA binding. We suggest that Finb/RREB-1 should be considered a potentiator of transcription, representing a distinct category of transcription-regulating proteins.

关键词： .binding site Gene Promoter DNA-binding basic helix-loop-helix potentiation enteroendocrine BETA NeuroD Finb/RREB

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Expression of a novel bHLH-Zip gene in human testis

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Asian Journal of Andrology 2003年第2期5卷 83-88页

作者： Jia-HaoSHA Zuo-MinZHOU Jian-MinLI MingLIN: HuiZHU HuZHU Ya-DongZHOU Li-LongWANG Yi-QuanWAIG Kai-YaZHOU Keylaboratoryofreproductivemedicine NanjingmedicalUniversityNanjing210029China Instituteofgeneticresources NanjingnormalUniversityNanjing210029China

Aim: To identify specifically expressed genes in the adult and fetal testes. Methods: A human testis cDNA microarray was established. Then the mRNA of adult and fetal testis was purified and probes were prepared by a reverse transcription reaction with the testis mRNA as template. The microarray was hybridized with probes of adult and fetal testes. The nucleic sequences of differentially expressed genes were determined and homologies were searched in the databases of the GenBank. Results: When hybridized with adult or fetal testis probes, the positive clones were 96.8 % and 95.4 %, respectively. Among these genes, one was a new testis-specific gene, which was named TSP1. TSP1 was highly expressed in human adult testis. The cDNA of TSP1 was 1,484 bp in length. The cDNA sequence of this clone was deposited in the Genbank (AF333098). TSP1 was also determined as Interim Gen Symbol (Unigene, No. Hs.98266). Protein analysis showed that TSP1 contained two functional domains: an N-terminal basic helix-loop-helix (bHLH) and a C-terminal leucine zipper (Zip). Homologous analysis showed that the 430 amino acid sequences deduced from the 1,293 bp open reading frame (ORF) had a homology with the human gene FLJ2509 (AK098575). TSP1 had also a sequence homology with Spz 1 protein of mouse. Expression profiles showed that TSP1 was specifically and strongly expressed in the testis. Conclusion: TSP1 is a gene highly expressed in adult testis. It may play an important role in spermatogenesis in the humans.

关键词： basic helix-loop-helix leucine zipper testis spermatogenesis DNA microarrays

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DNazyme-mediated cleavage of Twist transcripts and increase in cellular apoptosis

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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 2003年第1期300卷 178-181页

作者： Hjiantoniou, E Iseki, S Uney, JB Phylactou, LA Cyprus Inst Neurol & Genet CY-1683 Nicosia Cyprus Tokyo Med & Dent Univ Grad Sch Sect Mol Craniofacial Embryol Bunkyo Ku Tokyo 1138549 Japan URCN Bristol BS2 8HW Avon England Univ Bristol Div Med MRC Ctr Synapt Plast Bristol BS2 8HW Avon England

DNazymes is a group of catalytic nucleic acids that can be designed to cleave target mRNA molecules in a base-specific way. Twist is a basic helix-loop-helix transcription factor that is involved in the regulation of cellular differentiation and apoptosis. Moreover, it was shown to function in skull development and cause craniosynostosis. DZ-TWT DNuzyme as designed to downregulate Twist expression. The ability of DZ-TWT to cleave mouse Twist mRNA was first shown in a cell-free environment against full-length Twist mRNA. Following transfections of the DZ-TWT in C3H10T1/2 cells a significant reduction of Twist mRNA levels was observed. This was accompanied by a significant rise in p21 mRNA levels. Finally. DZ-TWT transfections resulted in an increase of cellular apoptosis, demonstrating the importance of Twist in apoptotic pathways. These results prove the Usefulness of DNazymes to characterize Twist gene function and further experiments in animals should demonstrate its complete physiological role. (C) 2002 Elsevier Science (USA). All rights reserved.

关键词： DNazyme Twist apoptosis basic helix-loop-helix

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Mechanisms of neuroendocrine differentiation in pulmonary neuroendocrine cells and small cell carcinoma

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ENDOCRINE PATHOLOGY 2003年第2期14卷 133-139页

作者： Ito, T Udaka, N Okudela, K Yazawa, T Kitamura, H Yokohama City Univ Dept Pathol Sch Med Yokohama Kanagawa 232 Japan

We review the significance of a network of proneural basic helix-loop-helix (bHLH) factors. Immunohistochemically, pulmonary neuroendocrine cells (PNECs) are positive for Mash1, one of the activator bHLHs, and non-PNECs such as Clara cells are positive for Hes1, one of the repressor bHLHs. Since mice deficient for the Mash1 gene do not possess PNEC and mice deficient for the Hes1 gene have many PNECs, it is suggested that a network of bHLHs work in cell fate determination of lung epithelium. Moreover, the Notch pathway could play a role in cell differentiation mechanisms in the lung because this signaling pathway has been reported to work in various tissues. PNECs have been reported to modulate various nonneoplastic human lung diseases. We demonstrate that PNECs in usual interstitial pneumonia and hASH1 (human homolog of Mash1) are upregulated in diseased lung tissues. Moreover, studies of small cell carcinoma and non-small cell carcinoma suggest that neuroendocrine differentiation could be regulated by hASH1. In non-small cell carcinoma, Hes1 and Notch signaling may have roles in maintaining cell differentiation. Thus, a network of bHLHs and Notch signaling are important in cell differentiation of normal and pathologic lung epithelial cells.

关键词： basic helix-loop-helix pulmonary neuroendocrine cells notch signaling neuroendocrine differentiation

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Identification of BOIP, a novel cDNA highly expressed during spermatogenesis that encodes a protein interacting with the orange domain of the hairy-related transcription factor HRT1/Hey1 in Xenopus and mouse

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DEVELOPMENTAL DYNAMICS 2003年第4期228卷 716-725页

作者： Van Wayenbergh, R Taelman, V Pichon, B Fischer, A Kricha, S Gessler, M Christophe, D Bellefroid, EJ Free Univ Brussels IBMM Lab Embryol Mol B-6041 Gosselies Belgium Free Univ Brussels IRIBHM B-6041 Gosselies Belgium Univ Wurzburg Theodor Boveri Inst Bioctr Inst Physiol Chem 1 Wurzburg Germany

Hairy-related transcription factor (HRT/Hey) genes encode a novel subfamily of basic helix-loop-helix (bHLH) transcription factors related to the Drosophila hairy and Enhancer-of-split (E(spl)) and the mammalian HES proteins that function as downstream mediators of Notch signaling. Using the yeast two-hybrid approach, a previously uncharacterized protein was identified in Xenopus that interacts with XHRT1 (originally referred to as bc8), one member of the HRT/Hey subclass. This protein is evolutionarily conserved in chordates. It binds to sequences adjacent to the bHLH domain of XHRT1 known as the Orange domain and has been named bc8 Orange interacting protein (BOIP). BOW shows a rather uniform subcellular localization and is recruited to the nucleus upon binding to XHRT1. In Xenopus, XBOIP mRNA is detected by RNase protection analysis throughout embryogenesis. In the adult, the strongest expression is detected in testis. In the mouse, high levels of BOIP mRNA are also found in adult testis. No expression is detected in the embryo and in any of the other adult organs tested. In situ, hybridization revealed that BOIP transcripts were detected almost exclusively in round spermatids and that this expression overlaps with that of Hey1 (HRT1), which is expressed throughout spermatogenesis. In view of the importance of the Orange domain for HRT/Hey function, the newly identified BOIP proteins may serve as regulators specifically of HRT1/Hey1 activity. (C) 2003 Wiley-Liss, Inc.

关键词： BOIP basic helix-loop-helix hairy-related transcription factor (HRT) HRT1 Hey1 mouse Xenopus spermatogenesis

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