scholarly journals Xenopus laevis FGF16 activates the expression of genes coding for the transcription factors Sp5 and Sp5l

2019 ◽  
Vol 63 (11-12) ◽  
pp. 631-639
Author(s):  
Michael Elsy ◽  
Abigail Rowbotham ◽  
Hannah Lord ◽  
Harry V. Isaacs ◽  
Mary E. Pownall
Keyword(s):  
Transcription Factors ◽  
Xenopus Laevis ◽  
Mapk Pathway ◽  
In Situ Hybridisation ◽  
Dorsal Side ◽  
Otic Vesicle ◽  
Signalling Molecules ◽  
Expression Of Genes ◽  
Branchial Arches

Fibroblast growth factors (FGFs) comprise a family of signalling molecules with essential roles in early embryonic development across animal species. The role of FGFs in mesoderm formation and patterning in Xenopus has been particularly well studied. However, little is known about FGF16 in Xenopus. Using in situ hybridisation, we uncover the expression pattern of FGF16 during early Xenopus laevis development, which has not been previously described. We show that the zygotic expression of FGF16 is activated in the mesoderm of the early gastrula as a ring around the blastopore, with its first accumulation at the dorsal side of the embryo. Later, FGF16 expression is found in the otic vesicle, the branchial arches and the anterior pituitary, as well as in the chordal neural hinge region of the tailbud. In addition, we show that FGF16 can activate the MAPK pathway and expression of sp5 and sp5l. Like FGF16, sp5 is expressed in the otic vesicle and the branchial arches, with all three of these genes being expressed in the tailbud. These data provide evidence that FGF16 is present in the early mesoderm and can activate the expression of developmentally important transcription factors.

scholarly journals Expression patterns of signalling molecules and transcription factors in the early rabbit embryo and their significance for modelling amniote axis formation

2021 ◽  
Author(s):  
Ruben Plöger ◽  
Christoph Viebahn
Keyword(s):  
Transcription Factors ◽  
Expression Patterns ◽  
In Situ Hybridisation ◽  
Body Plan ◽  
The Body ◽  
Anchor Point ◽  
Axis Formation ◽  
Point Model ◽  
Signalling Molecules ◽  
Rabbit Embryo

AbstractThe anterior-posterior axis is a central element of the body plan and, during amniote gastrulation, forms through several transient domains with specific morphogenetic activities. In the chick, experimentally proven activity of signalling molecules and transcription factors lead to the concept of a ‘global positioning system’ for initial axis formation whereas in the (mammotypical) rabbit embryo, a series of morphological or molecular domains are part of a putative ‘three-anchor-point model’. Because circular expression patterns of genes involved in axis formation exist in both amniote groups prior to, and during, gastrulation and may thus be suited to reconcile these models, the expression patterns of selected genes known in the chick, namely the ones coding for the transcription factors eomes and tbx6, the signalling molecule wnt3 and the wnt inhibitor pkdcc, were analysed in the rabbit embryonic disc using in situ hybridisation and placing emphasis on their germ layer location. Peripheral wnt3 and eomes expression in all layers is found initially to be complementary to central pkdcc expression in the hypoblast during early axis formation. Pkdcc then appears — together with a posterior-anterior gradient in wnt3 and eomes domains — in the epiblast posteriorly before the emerging primitive streak is marked by pkdcc and tbx6 at its anterior and posterior extremities, respectively. Conserved circular expression patterns deduced from some of this data may point to shared mechanisms in amniote axis formation while the reshaping of localised gene expression patterns is discussed as part of the ‘three-anchor-point model’ for establishing the mammalian body plan.

scholarly journals HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

2021 ◽  
Vol 9 (1) ◽  
pp. 144
Author(s):  
Sung-Hun Son ◽  
Mi-Kyung Lee ◽  
Ye-Eun Son ◽  
Hee-Soo Park
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Phenotypic Analysis ◽  
Spore Viability ◽  
Fungal Development ◽  
Expression Of Genes ◽  
Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

scholarly journals Expression Characterization of Flavonoid Biosynthetic Pathway Genes and Transcription Factors in Peanut Under Water Deficit Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Ghulam Kubra ◽  
Maryam Khan ◽  
Faiza Munir ◽  
Alvina Gul ◽  
Tariq Shah ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Water Deficit ◽  
Biosynthetic Pathway ◽  
Correlational Analysis ◽  
Accumulation Pattern ◽  
Yield Production ◽  
Expression Of Genes ◽  
Flavonoid Biosynthetic Pathway ◽  
Wide Range

Drought is one of the hostile environmental stresses that limit the yield production of crop plants by modulating their growth and development. Peanut (Arachis hypogaea) has a wide range of adaptations to arid and semi-arid climates, but its yield is prone to loss due to drought. Other than beneficial fatty acids and micronutrients, peanut harbors various bioactive compounds including flavonoids that hold a prominent position as antioxidants in plants and protect them from oxidative stress. In this study, understanding of the biosynthesis of flavonoids in peanut under water deficit conditions was developed through expression analysis and correlational analysis and determining the accumulation pattern of phenols, flavonols, and anthocyanins. Six peanut varieties (BARD479, BARI2011, BARI2000, GOLDEN, PG1102, and PG1265) having variable responses against drought stress have been selected. Higher water retention and flavonoid accumulation have been observed in BARI2011 but downregulation has been observed in the expression of genes and transcription factors (TFs) which indicated the maintenance of normal homeostasis. ANOVA revealed that the expression of flavonoid genes and TFs is highly dependent upon the genotype of peanut in a spatiotemporal manner. Correlation analysis between expression of flavonoid biosynthetic genes and TFs indicated the role of AhMYB111 and AhMYB7 as an inhibitor for AhF3H and AhFLS, respectively, and AhMYB7, AhTTG1, and AhCSU2 as a positive regulator for the expression of Ah4CL, AhCHS, and AhF3H, respectively. However, AhbHLH and AhGL3 revealed nil-to-little relation with the expression of flavonoid biosynthetic pathway genes. Correlational analysis between the expression of TFs related to the biosynthesis of flavonoids and the accumulation of phenolics, flavonols, and anthocyanins indicated coregulation of flavonoid synthesis by TFs under water deficit conditions in peanut. This study would provide insight into the role of flavonoid biosynthetic pathway in drought response in peanut and would aid to develop drought-tolerant varieties of peanut.

Molecular Biology and the Major Psychoses

1997 ◽  
Vol 31 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Andrew Lloyd ◽  
Gavin Dixon ◽  
Xu Feng Huang ◽  
Phillip Ward ◽  
Stan Catts ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Messenger Rna ◽  
Potential Role ◽  
In Situ Hybridisation ◽  
Northern Analysis ◽  
Expression Of Genes ◽  
Expression Studies ◽  
Biological Studies

Objective:To highlight the potential role of molecular biological studies in examining the expression of genes of interest in brain tissue to elucidate the pathophysiological basis of the major psychoses. Method:To review the principles underlying the available techniques for expression studies. Results:Detection of messenger RNA by in situ hybridisation and quantitation by Northern analysis are powerful tools to detect abnormalities in gene expression in brain tissue. Conclusion:The availability of simple techniques to examine the expression of RNA and protein products of individual genes, including examination at the level of individual cells, offers a clear opportunity to define the molecular basis of the major psychoses.

Organization of chromatin in cancer cells: role of signalling pathways

1999 ◽  
Vol 77 (4) ◽  
pp. 265-275 ◽  
Author(s):  
J R Davie ◽  
S K Samuel ◽  
V A Spencer ◽  
L T Holth ◽  
D N Chadee ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Cancer Cells ◽  
Histone Deacetylase ◽  
Nuclear Matrix ◽  
Nuclear Dna ◽  
Mapk Pathway ◽  
Signalling Pathway ◽  
Signalling Pathways ◽  
Chemical Signalling

The role of mechanical and chemical signalling pathways in the organization and function of chromatin is the subject of this review. The mechanical signalling pathway consists of the tissue matrix system that links together the three-dimensional skeletal networks, the extracellular matrix, cytoskeleton, and nuclear matrix. Intermediate filament proteins are associated with nuclear DNA, suggesting that intermediate filaments may have a role in the organization of chromatin. In human hormone-dependent breast cancer cells, the interaction between cytokeratins and chromatin is regulated by estrogens. Transcription factors, histone acetyltransferases, and histone deacetylases, which are associated with the nuclear matrix, are components of the mechanical signalling pathway. Recently, we reported that nuclear matrix-bound human and chicken histone deacetylase 1 is associated with nuclear DNA in situ, suggesting that histone deacetylase has a role in the organization of nuclear DNA. Chemical signalling pathways such as the Ras/mitogen-activated protein kinase (Ras/MAPK) pathway stimulate the activity of kinases that modify transcription factors, nonhistone chromosomal proteins, and histones. The levels of phosphorylated histones are increased in mouse fibroblasts transformed with oncogenes, the products of which stimulate the Ras/MAPK pathway. Histone phosphorylation may lead to decondensation of chromatin, resulting in aberrant gene expression.Key words: histone acetylation, histone phosphorylation, nuclear matrix, cytoskeleton, histone deacetylase, cancer.

scholarly journals The Role of Some Transcription Factors in Expression of GyrA and GyrB Following Exposure to Ciprofloxacin

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Razieh Pourahmad Jaktaji ◽  
Seyed Mohammad Lesani ◽  
Hoda Akhavan ◽  
Maryam Tanhaei
Keyword(s):  
Transcription Factors ◽  
Dna Supercoiling ◽  
Transcription Activator ◽  
Expression Of Genes ◽  
Polymerase Chain ◽  
Presence And Absence ◽  
Theoretical Results ◽  
Different Levels ◽  
Soxs Gene

Background: GyrA and gyrB genes encode DNA gyrase subunits. This enzyme regulates DNA supercoiling. Inhibitors of this enzyme, such as ciprofloxacin, may change the level of supercoiling and the expression level of genes, including gyrA and gyrB. Objectives: The aims of this research were first to select some transcription factors, which regulate the expression of gyrA and gyrB. Secondly, the effect of these transcription factors was investigated on the expression of these genes in Escherichia coli mutants with different levels of resistance to ciprofloxacin in the presence and absence of these transcription factors. Methods: For this purpose, the online software called Promoter Analyzer in Virtual Footprint version 3 was used to find and select some transcription factors. The relative expression of genes was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Results: Theoretical results showed that CspA, FhlA, and SoxS transcription factors (with a score of match higher than 6), could be selected for further analysis. The expression of gyrA and gyrB genes remained unchanged in the presence and absence of CspA and FhlA transcription factors following exposure to the low amount of ciprofloxacin. However, SoxS transcription activator might have indirect effects on the expression of these genes, as soxS gene was overexpressed following treatment with a higher amount of ciprofloxacin. Conclusions: It is concluded that overexpression of gyrA and gyrB genes is not dependent on CspA and FhlA transcription factors, but may be dependent indirectly on regulatory proteins involved in oxidative stress following exposure to ciprofloxacin.

Overexpression of a cellular retinoic acid binding protein (xCRABP) causes anteroposterior defects in developing Xenopus embryos

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 973-985
Author(s):  
E.J. Dekker ◽  
M.J. Vaessen ◽  
C. van den Berg ◽  
A. Timmermans ◽  
S. Godsave ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Xenopus Laevis ◽  
Target Genes ◽  
Hox Genes ◽  
Binding Protein ◽  
In Situ Hybridisation ◽  
Brain Structures ◽  
Dorsal Side ◽  
Reading Frame ◽  
Acid Binding Protein

We have isolated the first Xenopus laevis cDNA coding for a cellular retinoic acid binding protein (xCRABP). xCRABP contains a single open reading frame, coding for an approximately 15 × 10(3) M(r) protein. Northern blot analysis shows that this cDNA hybridizes to a mRNA that is expressed both maternally and zygotically and which already reaches maximal expression during gastrulation (much earlier than previously described CRABP genes from other species). In situ hybridisation showed that at the onset of gastrulation, xCRABP mRNA is localised at the dorsal side of the embryo, in the ectoderm and in invaginating mesoderm. xCRABP expression then rapidly resolves into two domains; a neural domain, which becomes localised in the anterior hindbrain, and a posterior domain in neuroectoderm and mesoderm. These two domains were already evident by the mid-gastrula stage. We investigated the function of xCRABP by injecting fertilized eggs with an excess of sense xCRABP mRNA and examined the effects on development. We observed embryos with clear antero-posterior defects, many of which resembled the effects of treating Xenopus gastrulae with all-trans retinoic acid. Notably, the heart was deleted, anterior brain structures and the tail were reduced, and segmentation of the hindbrain was inhibited. The effects of injecting xCRABP transcripts are compatible with the idea that xCRABP overexpression modulates the action of an endogenous retinoid, thereby regulating the expression of retinoid target genes, such as Hox genes. In support of this, we showed that the expression of two Xenopus Hoxb genes, Hoxb-9 and Hoxb-4, is strongly enhanced by xCRABP over-expression. These results suggest that xCRABP expression may help to specify the anteroposterior axis during the early development of Xenopus laevis.

scholarly journals Otic Neurogenesis in Xenopus laevis: Proliferation, Differentiation, and the Role of Eya1

2021 ◽  
Vol 15 ◽  
Author(s):  
Suad Hamdan Almasoudi ◽  
Gerhard Schlosser
Keyword(s):  
Xenopus Laevis ◽  
Neuronal Differentiation ◽  
Underlying Mechanism ◽  
Otic Vesicle ◽  
Transcriptional Coactivator ◽  
Differentiation Markers ◽  
Apicobasal Polarity ◽  
Ganglion Neurons ◽  
Peripheral Cells

Using immunostaining and confocal microscopy, we here provide the first detailed description of otic neurogenesis in Xenopus laevis. We show that the otic vesicle comprises a pseudostratified epithelium with apicobasal polarity (apical enrichment of Par3, aPKC, phosphorylated Myosin light chain, N-cadherin) and interkinetic nuclear migration (apical localization of mitotic, pH3-positive cells). A Sox3-immunopositive neurosensory area in the ventromedial otic vesicle gives rise to neuroblasts, which delaminate through breaches in the basal lamina between stages 26/27 and 39. Delaminated cells congregate to form the vestibulocochlear ganglion, whose peripheral cells continue to proliferate (as judged by EdU incorporation), while central cells differentiate into Islet1/2-immunopositive neurons from stage 29 on and send out neurites at stage 31. The central part of the neurosensory area retains Sox3 but stops proliferating from stage 33, forming the first sensory areas (utricular/saccular maculae). The phosphatase and transcriptional coactivator Eya1 has previously been shown to play a central role for otic neurogenesis but the underlying mechanism is poorly understood. Using an antibody specifically raised against Xenopus Eya1, we characterize the subcellular localization of Eya1 proteins, their levels of expression as well as their distribution in relation to progenitor and neuronal differentiation markers during otic neurogenesis. We show that Eya1 protein localizes to both nuclei and cytoplasm in the otic epithelium, with levels of nuclear Eya1 declining in differentiating (Islet1/2+) vestibulocochlear ganglion neurons and in the developing sensory areas. Morpholino-based knockdown of Eya1 leads to reduction of proliferating, Sox3- and Islet1/2-immunopositive cells, redistribution of cell polarity proteins and loss of N-cadherin suggesting that Eya1 is required for maintenance of epithelial cells with apicobasal polarity, progenitor proliferation and neuronal differentiation during otic neurogenesis.

RNA helicase Ddx39 is expressed in the developing central nervous system, limb, otic vesicle, branchial arches and facial mesenchyme of Xenopus laevis

2010 ◽  
Vol 10 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Jonathan M. Wilson ◽  
Reyna I. Martinez-De Luna ◽  
Heithem M. El Hodiri ◽  
Rosamund Smith ◽  
Michael W. King ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Xenopus Laevis ◽  
Rna Helicase ◽  
Otic Vesicle ◽  
Branchial Arches

scholarly journals The “Janus” Role of C/EBPs Family Members in Cancer Progression

2020 ◽  
Vol 21 (12) ◽  
pp. 4308 ◽  
Author(s):  
Manlio Tolomeo ◽  
Stefania Grimaudo
Keyword(s):  
Transcription Factors ◽  
Cancer Progression ◽  
Tumor Suppressors ◽  
Cellular Response ◽  
Cellular Proliferation ◽  
Cell Types ◽  
Tumor Promoters ◽  
Expression Of Genes ◽  
Molecular Aspects

CCAAT/enhancer-binding proteins (C/EBPs) constitute a family of transcription factors composed of six members that are critical for normal cellular differentiation in a variety of tissues. They promote the expression of genes through interaction with their promoters. Moreover, they have a key role in regulating cellular proliferation through interaction with cell cycle proteins. C/EBPs are considered to be tumor suppressor factors due to their ability to arrest cell growth (contributing to the terminal differentiation of several cell types) and for their role in cellular response to DNA damage, nutrient deprivation, hypoxia, and genotoxic agents. However, C/EBPs can elicit completely opposite effects on cell proliferation and cancer development and they have been described as both tumor promoters and tumor suppressors. This “Janus” role of C/EBPs depends on different factors, such as the type of tumor, the isoform/s expressed in cells, the type of dimerization (homo- or heterodimerization), the presence of inhibitory elements, and the ability to inhibit the expression of other tumor suppressors. In this review, we discuss the implication of the C/EBPs family in cancer, focusing on the molecular aspects that make these transcription factors tumor promoters or tumor suppressors.

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