Characterization of a notochord-specific enhancer from the Brachyury promoter region of the ascidian, Ciona intestinalis

Development ◽  
1997 ◽  
Vol 124 (3) ◽  
pp. 589-602 ◽  
Author(s):  
J.C. Corbo ◽  
M. Levine ◽  
R.W. Zeller

We present evidence that the embryo of the ascidian, Ciona intestinalis, is an easily manipulated system for investigating the establishment of basic chordate tissues and organs. Ciona has a small genome, and simple, well-defined embyronic lineages. Here, we examine the regulatory mechanisms underlying the differentiation of the notochord. Particular efforts center on the regulation of a notochord-specific Ciona Brachyury gene (Ci-Bra). An electroporation method was devised for the efficient incorporation of transgenic DNA into Ciona embryos. This method permitted the identification of a minimal, 434 bp enhancer from the Ci-Bra promoter region that mediates the notochord-restricted expression of both GFP and lacZ reporter genes. This enhancer contains a negative control region that excludes Ci-Bra expression from inappropriate embryonic lineages, including the trunk mesenchyme and tail muscles. Evidence is presented that the enhancer is activated by a regulatory element which is closely related to the recognition sequence of the Suppressor of Hairless transcription factor, thereby raising the possibility that the Notch signaling pathway plays a role in notochord differentiation. We discuss the implications of this analysis with regard to the evolutionary conservation of integrative enhancers, and the subdivision of the axial and paraxial mesoderm in vertebrates.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Amita Mohan ◽  
Amandeep K. Dhaliwal ◽  
Ragupathi Nagarajan ◽  
Kulvinder S. Gill

AbstractAuxin is an important phytohormone that regulates response, differentiation, and development of plant cell, tissue, and organs. Along with its local production, long-distance transport coordinated by the efflux/influx membrane transporters is instrumental in plant development and architecture. In the present study, we cloned and characterized a wheat (Triticum aestivum) auxin efflux carrier ABCB1. The TaABCB1 was physically localized to the proximal 15% of the short arm of wheat homoeologous group 7 chromosomes. Size of the Chinese spring (CS) homoeologs genomic copies ranged from 5.3–6.2 kb with the 7A copy being the largest due to novel insertions in its third intron. The three homoeologous copies share 95–97% sequence similarity at the nucleotide, 98–99% amino acid, and overall Q-score of 0.98 at 3-D structure level. Though detected in all analyzed tissues, TaABCB1 predominantly expressed in the meristematic tissues likely due to the presence of meristem-specific activation regulatory element identified in the promoter region. RNAi plants of TaABCB1 gene resulted in reduced plant height and increased seed width. Promoter analysis revealed several responsive elements detected in the promoter region including that for different hormones as auxin, gibberellic acid, jasmonic acid and abscisic acid, light, and circadian regulated elements.


1992 ◽  
Vol 267 (36) ◽  
pp. 26011-26016 ◽  
Author(s):  
Y.S. Li ◽  
R.M. Hoffman ◽  
M.M. Le Beau ◽  
R Espinosa ◽  
N.A. Jenkins ◽  
...  

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1335-1341
Author(s):  
Izabela Noll ◽  
Steffen Müller ◽  
Albrecht Klein

Abstract Methanococcus voltae harbors genetic information for two pairs of homologous [NiFe]-hydrogenases. Two of the enzymes contain selenocysteine, while the other two gene groups encode apparent isoenzymes that carry cysteinyl residues in the homologous positions. The genes coding for the selenium-free enzymes, frc and vhc, are expressed only under selenium limitation. They are transcribed out of a common intergenic region. A series of deletions made in the intergenic region localized a common negative regulatory element for the vhc and frc promoters as well as two activator elements that are specific for each of the two transcription units. Repeated sequences, partially overlapping the frc promoter, were also detected. Mutations in these repeated heptanucleotide sequences led to a weak induction of a reporter gene under the control of the frc promoters in the presence of selenium. This result suggests that the heptamer repeats contribute to the negative regulation of the frc transcription unit.


2019 ◽  
Vol 29 (1) ◽  
pp. 32157
Author(s):  
Luciane Madureira Almeida ◽  
Elisa Flávia Luiz Cardoso Bailão ◽  
Illana Reis Pereira ◽  
Fabrício Alves Ferreira ◽  
Patrícia Lima D'Abadia ◽  
...  

AIMS: To perform a physicochemical and phytochemical characterization of Jatropha curcas latex and to investigate its antiangiogenic potential. METHODS: We performed an initial physicochemical characterization of J. curcas latex using thermal gravimetric analyses and Fourier Transform Infrared spectroscopy. After that, phenols, tannins and flavonoids were quantified. Finally, the potential of J. curcas latex to inhibit angiogenesis was evaluated using the chick chorioallantoic membrane model. Five groups of 20 fertilized chicken eggs each had the chorioallantoic membrane exposed to the following solutions: (1) water, negative control; (2) dexamethasone, angiogenesis inhibitor; (3) Regederm®, positive control; (4) 25% J. curcas latex diluted in water; (5) 50% J. curcas latex diluted in water; and (6) J. curcas crude latex. Analysis of the newly-formed vascular net was made through captured images and quantification of the number of pixels. Histological analyses were performed to evaluate the inflammation, neovascularization, and hyperemia parameters. The results were statically analyzed with a significance level set at p ˂0.05.RESULTS: Physicochemical characterization showed that J. curcas latex presented a low amount of cis-1.4-polyisoprene, which reduced its elasticity and thermal stability. Phytochemical analyses of J. curcas latex identified a substantial amount of phenols, tannins, and flavonoids (51.9%, 11.8%, and 0.07% respectively). Using a chick chorioallantoic membrane assay, we demonstrated the antiangiogenic potential of J. curcas latex. The latex induced a decrease in the vascularization of the membranes when compared with neutral and positive controls (water and Regederm®). However, when compared with the negative control (dexamethasone), higher J. curcas latex concentrations showed no significant differences.CONCLUSIONS: J. curcas latex showed low thermal stability, and consisted of phenols, tannins, and flavonoids, but little or no rubber. Moreover, this latex demonstrated a significant antiangiogenic activity on a chick chorioallantoic membrane model. The combination of antimutagenic, cytotoxic, antioxidant and antiangiogenic properties makes J. curcas latex a potential target for the development of new drugs.


1995 ◽  
Vol 92 (26) ◽  
pp. 12515-12519 ◽  
Author(s):  
N. Pillet ◽  
C. Bonny ◽  
D. F. Schorderet
Keyword(s):  

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