NeuroM, a neural helix-loop-helix transcription factor, defines a new transition stage in neurogenesis

Development ◽  
1997 ◽  
Vol 124 (17) ◽  
pp. 3263-3272 ◽  
Author(s):  
T. Roztocil ◽  
L. Matter-Sadzinski ◽  
C. Alliod ◽  
M. Ballivet ◽  
J.M. Matter
Keyword(s):  
Nervous System ◽  
Transcription Factor ◽  
Mitotic Cycle ◽  
Ventricular Zone ◽  
Helix Loop Helix ◽  
E Box ◽  
Genes Encoding ◽  
Developing Nervous System

Genes encoding transcription factors of the helix-loop-helix family are essential for the development of the nervous system in Drosophila and vertebrates. Screens of an embryonic chick neural cDNA library have yielded NeuroM, a novel neural-specific helix-loop-helix transcription factor related to the Drosophila proneural gene atonal. The NeuroM protein most closely resembles the vertebrate NeuroD and Nex1/MATH2 factors, and is capable of transactivating an E-box promoter in vivo. In situ hybridization studies have been conducted, in conjunction with pulse-labeling of S-phase nuclei, to compare NeuroM to NeuroD expression in the developing nervous system. In spinal cord and optic tectum, NeuroM expression precedes that of NeuroD. It is transient and restricted to cells lining the ventricular zone that have ceased proliferating but have not yet begun to migrate into the outer layers. In retina, NeuroM is also transiently expressed in cells as they withdraw from the mitotic cycle, but persists in horizontal and bipolar neurons until full differentiation, assuming an expression pattern exactly complementary to NeuroD. In the peripheral nervous system, NeuroM expression closely follows cell proliferation, suggesting that it intervenes at a similar developmental juncture in all parts of the nervous system. We propose that availability of the NeuroM helix-loop-helix factor defines a new stage in neurogenesis, at the transition between undifferentiated, premigratory and differentiating, migratory neural precursors.

scholarly journals An activation domain of the helix-loop-helix transcription factor E2A shows cell type preference in vivo in microinjected zebra fish embryos.

1996 ◽  
Vol 16 (4) ◽  
pp. 1714-1721 ◽  
Author(s):  
F Argenton ◽  
Y Arava ◽  
A Aronheim ◽  
M D Walker
Keyword(s):  
Gene Expression ◽  
Nervous System ◽  
Transcription Factor ◽  
Transcription Activation ◽  
Cell Types ◽  
Zebra Fish ◽  
Reporter Plasmid ◽  
Activation Domains ◽  
Helix Loop Helix

The E2A protein is a mammalian transcription factor of the helix-loop-helix family which is implicated in cell-specific gene expression in several cell lineages. Mouse E2A contains two independent transcription activation domains, ADI and ADII; whereas ADI functions effectively in a variety of cultured cell lines, ADII shows preferential activity in pancreatic beta cells. To analyze this preferential activity in an in vivo setting, we adapted a system involving transient gene expression in microinjected zebra fish embryos. Fertilized one- to four-cell embryos were coinjected with an expression plasmid and a reporter plasmid. The expression plasmids used encode the yeast Gal4 DNA-binding domain (DBD) alone, or Gal4 DBD fused to ADI, ADII, or VP16. The reporter plasmid includes the luciferase gene linked to a promoter containing repeats of UASg, the Gal4-binding site. Embryo extracts prepared 24 h after injection showed significant luciferase activity in response to each of the three activation domains. To determine the cell types in which the activation domains were functioning, a reporter plasmid encoding beta-galactosidase and then in situ staining of whole embryos were used. Expression of ADI led to activation in all major groups of cell types of the embryo (skin, sclerotome, myotome, notochord, and nervous system). On the other hand, ADII led to negligible expression in the sclerotome, notochord, and nervous system and much more frequent expression in the myotome. Parallel experiments conducted with transfected mammalian cells have confirmed that ADII shows significant activity in myoblast cells but little or no activity in neuronal precursor cells, consistent with our observations in zebra fish. This transient-expression approach permits rapid in vivo analysis of the properties of transcription activation domains: the data show that ADII functions preferentially in cells of muscle lineage, consistent with the notion that certain activation domains contribute to selective gene activation in vivo.

scholarly journals The Basic Helix-Loop-Helix Transcription Factor NeuroD1 Facilitates Interaction of Sp1 with the Secretin Gene Enhancer

2007 ◽  
Vol 27 (22) ◽  
pp. 7839-7847 ◽  
Author(s):  
Subir K. Ray ◽  
Andrew B. Leiter
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Target Genes ◽  
Zinc Fingers ◽  
Homeodomain Proteins ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Gene Enhancer ◽  
Genes Encoding

ABSTRACT The basic helix-loop-helix transcription factor NeuroD1 is required for late events in neuronal differentiation, for maturation of pancreatic β cells, and for terminal differentiation of enteroendocrine cells expressing the hormone secretin. NeuroD1-null mice demonstrated that this protein is essential for expression of the secretin gene in the murine intestine, and yet it is a relatively weak transcriptional activator by itself. The present study shows that Sp1 and NeuroD1 synergistically activate transcription of the secretin gene. NeuroD1, but not its widely expressed dimerization partner E12, physically interacts with the C-terminal 167 amino acids of Sp1, which include its DNA binding zinc fingers. NeuroD1 stabilizes Sp1 DNA binding to an adjacent Sp1 binding site on the promoter to generate a higher-order DNA-protein complex containing both proteins and facilitates Sp1 occupancy of the secretin promoter in vivo. NeuroD-dependent transcription of the genes encoding the hormones insulin and proopiomelanocortin is potentiated by lineage-specific homeodomain proteins. The stabilization of binding of the widely expressed transcription factor Sp1 to the secretin promoter by NeuroD represents a distinct mechanism from other NeuroD target genes for increasing NeuroD-dependent transcription.

scholarly journals Drosophila laminin: sequence of B2 subunit and expression of all three subunits during embryogenesis.

1989 ◽  
Vol 109 (5) ◽  
pp. 2441-2453 ◽  
Author(s):  
D J Montell ◽  
C S Goodman
Keyword(s):  
Nervous System ◽  
In Situ Hybridization ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cdna Sequence ◽  
Drosophila Embryogenesis ◽  
Substrate Adhesion ◽  
Genes Encoding ◽  
Developing Nervous System

In a previous study, we described the cloning of the genes encoding the three subunits of Drosophila laminin, a substrate adhesion molecule, and the cDNA sequence of the B1 subunit (Montell and Goodman, 1988). This analysis revealed the similarity of Drosophila laminin with the mouse and human complexes in subunit composition, domain structure, and amino acid sequence. In this paper, we report the deduced amino acid sequence of the B2 subunit. We then describe the expression and tissue distribution of the three subunits of laminin during Drosophila embryogenesis using both in situ hybridization and immunolocalization techniques, with particular emphasis on its expression in and around the developing nervous system.

A chicken achaete-scute homolog (CASH-1) is expressed in a temporally and spatially discrete manner in the developing nervous system

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 769-783 ◽  
Author(s):  
C.L. Jasoni ◽  
M.B. Walker ◽  
M.D. Morris ◽  
T.A. Reh
Keyword(s):  
Nervous System ◽  
Amino Acid ◽  
Progenitor Cell ◽  
Sequence Similarity ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Neuronal Progenitor ◽  
Discrete Manner ◽  
Developing Nervous System

We have identified a basic helix-loop-helix encoding cDNA from embryonic chicken retina which shares sequence similarity with the achaete-scute family of genes of Drosophila. The deduced amino acid sequence of this chicken achaete-scute homolog (CASH-1) is identical, over the region encoding the basic helix-loop-helix domain, to the recently identified mammalian achaete-scute homolog (MASH-1) and to the Xenopus homolog (XASH1), and 70% identical, over the same region, to Drosophila achaete-scute complex members. The expression of CASH-1 is restricted to subsets of neuronal progenitor cells in the developing chicken nervous system, similar in distribution to that reported for MASH-1 and XASH1. In addition, in situ localization in the retina reveals a dynamic character of expression of the gene in a particular region of the CNS, and suggests that the expression of CASH-1 may be important in defining a particular stage in the progenitor cell necessary for the differentiation of particular neuronal phenotypes.

scholarly journals Targeting the Microphthalmia Basic Helix-Loop-Helix–Leucine Zipper Transcription Factor to a Subset of E-Box Elements In Vitro and In Vivo

1998 ◽  
Vol 18 (12) ◽  
pp. 6930-6938 ◽  
Author(s):  
I. Aksan ◽  
C. R. Goding
Keyword(s):  
Transcription Factor ◽  
Leucine Zipper ◽  
Pigment Cells ◽  
Specific Gene ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
P Gene ◽  
E Box

ABSTRACT The development of melanocytes, which are pigment-producing cells responsible for skin, hair, and eye color, is absolutely dependent on the action of the microphthalmia basic helix-loop-helix–leucine zipper (bHLH-LZ) transcription factor (Mi); mice lacking a functional Mi protein are entirely devoid of pigment cells. Mi has been shown to activate transcription of the tyrosinase,TRP-1, TRP-2, and QNR-71 genes through specific E-box elements, most notably the highly conserved M box. We investigated the mechanism which enables Mi to be recruited specifically to a restricted subset of E boxes in target promoters while being prevented from binding E-box elements in other promoters. We show both in vitro and in vivo that the presence of a T residue flanking a CATGTG E box is an essential determinant of the ability of Mi to bind DNA, and we successfully predict that the CATGTG E box from the P gene would not bind Mi. In contrast, no specific requirement for the sequences flanking a CACGTG E box was observed, and no binding to an atypical E box in the c-Kit promoter was detected. The relevance of these observations to the control of melanocyte-specific gene expression was highlighted by the fact that the E-box elements located in thetyrosinase, TRP-1, TRP-2, andQNR-71 promoters without exception possess a 5′ flanking T residue which is entirely conserved between species as diverse as man and turtle. The ability of Mi to discriminate between different E-box motifs provides a mechanism to restrict the repertoire of genes which are likely to be regulated by Mi and provides insight into the ability of bHLH-LZ transcription factors to achieve the specificity required for the precise coordination of transcription during development.

Developmental programmes of growth and survival in early sensory neurons

1991 ◽  
Vol 331 (1261) ◽  
pp. 259-262
Keyword(s):  
Nervous System ◽  
Sensory Neurons ◽  
Neurotrophic Factor ◽  
Target Distance ◽  
Trophic Factor ◽  
Growth And Survival ◽  
Target Field ◽  
Developing Nervous System

In the developing vertebrate nervous system the survival of neurons becomes dependent on the supply of a neurotrophic factor from their targets when their axons reach these targets. To determine how the onset of neurotrophic factor dependency is coordinated with the arrival of axons in the target field, we have studied the growth and survival of four populations of cranial sensory neurons whose axons have markedly different distances to grow to reach their targets. Axonal growth rate both in vivo and in vitro is related to target distance; neurons with more distant targets grow faster. The onset trophic factor dependency in culture is also related to target distance; neurons with more distant targets survive longer before becoming trophic factor dependent. These data suggest that programmes of growth and survival in early neurons play an important role in coordinating the timing of trophic interactions in the developing nervous system.

scholarly journals Comparative Transcriptome Profiling Reveals Defense-Related Genes against Meloidogyne incognita Invasion in Tobacco

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 2081 ◽  
Author(s):  
Xiaohui Li ◽  
Xuexia Xing ◽  
Pei Tian ◽  
Mingzhen Zhang ◽  
Zhaoguang Huo ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Meloidogyne Incognita ◽  
Resistance Mechanism ◽  
Transcriptome Profiling ◽  
Ethylene Response Factor ◽  
Sequencing Analysis ◽  
Cell Wall Modification ◽  
Resistance Response ◽  
Helix Loop Helix ◽  
Genes Encoding

Root-knot nematodes Meloidogyne incognita are one of the most destructive pathogens, causing severe losses to tobacco productivity and quality. However, the underlying resistance mechanism of tobacco to M. incognita is not clear. In this study, two tobacco genotypes, K326 and Changbohuang, which are resistant and susceptible to M. incognita, respectively, were used for RNA-sequencing analysis. An average of 35 million clean reads were obtained. Compared with their expression levels in non-infected plants of the same genotype, 4354 and 545 differentially expressed genes (DEGs) were detected in the resistant and susceptible genotype, respectively, after M. incognita invasion. Overall, 291 DEGs, involved in diverse biological processes, were common between the two genotypes. Genes encoding toxic compound synthesis, cell wall modification, reactive oxygen species and the oxidative burst, salicylic acid signal transduction, and production of some other metabolites were putatively associated with tobacco resistance to M. incognita. In particular, the complex resistance response needed to overcome M. incognita invasion may be regulated by several transcription factors, such as the ethylene response factor, MYB, basic helix–loop–helix transcription factor, and indole acetic acid–leucine-resistant transcription factor. These results may aid in the identification of potential genes of resistance to M. incognita for tobacco cultivar improvement.

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