Ventral veinless, the gene encoding the Cf1a transcription factor, links positional information and cell differentiation during embryonic and imaginal development in Drosophila melanogaster

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3405-3416 ◽  
Author(s):  
J.F. de Celis ◽  
M. Llimargas ◽  
J. Casanova

The ventral veinless gene (vvl) encodes the previously identified Cf1a protein, a transcription factor containing a POU-domain. During embryonic development vvl function is required for the formation of the tracheal tree and in the patterning of the ventral ectoderm. During imaginal development vvl is required for cell proliferation and the differentiation of the wing veins. vvl expression is restricted to the regions where its function is required, and is dependent on the coordinate activities of signalling molecules such as decapentaplegic, wingless and hedgehog. vvl interacts with other genes involved in vein differentiation, including veinlet, thick veins, torpedo, decapentaplegic and Notch suggesting that vvl function may affect several cell-to-cell communication pathways. We propose that the gene vvl integrates information from different signalling molecules and regulates the expression of specific cell differentiation genes during tracheal development and vein differentiation.


2004 ◽  
Vol 24 (7) ◽  
pp. 2915-2922 ◽  
Author(s):  
Jane Goodall ◽  
Silvia Martinozzi ◽  
Timothy J. Dexter ◽  
Delphine Champeval ◽  
Suzanne Carreira ◽  
...  

ABSTRACT Constitutive activation of the Wnt/β-catenin signaling pathway is a notable feature of a large minority of cases of malignant melanoma, an aggressive and increasingly common cancer. The identification of target genes downstream from this pathway is therefore crucial to our understanding of the disease. The POU domain transcription factor Brn-2 has been implicated in control of proliferation and melanoma survival, and its expression is strongly upregulated in melanoma. We show here that in vivo Brn-2 is expressed in melanocytes but not in embryonic day 11.5 melanoblasts and that its expression is directly controlled by the Wnt/β-catenin signaling pathway in melanoma cell lines and in transgenic mice. Moreover, silent interfering RNA-mediated inhibition of Brn-2 expression in melanoma cells overexpressing β-catenin results in significantly decreased proliferation. These results, together with the observation that BRAF signaling also induces Brn-2 expression, reveal that Brn-2 is a focus for the convergence of two key melanoma-associated signaling pathways that are linked to cell proliferation.



Development ◽  
2001 ◽  
Vol 128 (21) ◽  
pp. 4165-4176 ◽  
Author(s):  
Heinz-Georg Belting ◽  
Giselbert Hauptmann ◽  
Dirk Meyer ◽  
Salim Abdelilah-Seyfried ◽  
Ajay Chitnis ◽  
...  

The vertebrate midbrain-hindbrain boundary (MHB) organizes patterning and neuronal differentiation in the midbrain and anterior hindbrain. Formation of this organizing center involves multiple steps, including positioning of the MHB within the neural plate, establishment of the organizer and maintenance of its regional identity and signaling activities. Juxtaposition of the Otx2 and Gbx2 expression domains positions the MHB. How the positional information is translated into activation of Pax2, Wnt1 and Fgf8 expression during MHB establishment remains unclear. In zebrafish spiel ohne grenzen (spg) mutants, the MHB is not established, neither isthmus nor cerebellum form, the midbrain is reduced in size and patterning abnormalities develop within the hindbrain. In spg mutants, despite apparently normal expression of otx2, gbx1 and fgf8 during late gastrula stages, the initial expression of pax2.1, wnt1 and eng2, as well as later expression of fgf8 in the MHB primordium are reduced. We show that spg mutants have lesions in pou2, which encodes a POU-domain transcription factor. Maternal pou2 transcripts are distributed evenly in the blastula, and zygotic expression domains include the midbrain and hindbrain primordia during late gastrulation. Microinjection of pou2 mRNA can rescue pax2.1 and wnt1 expression in the MHB of spg/pou2 mutants without inducing ectopic expression. This indicates an essential but permissive role for pou2 during MHB establishment. pou2 is expressed normally in noi/pax2.1 and ace/fgf8 zebrafish mutants, which also form no MHB. Thus, expression of pou2 does not depend on fgf8 and pax2.1. Our data suggest that pou2 is required for the establishment of the normal expression domains of wnt1 and pax2.1 in the MHB primordium.



Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1416-1416
Author(s):  
Grazia Fazio ◽  
Chiara Palmi ◽  
Greta Giordano Attianese ◽  
Andrea Biondi ◽  
Antonius Rolink ◽  
...  

Abstract The PAX5/TEL chimeric gene was cloned from the translocation t(9;12)(q11;p13) in an ALL patient. Recent data indicate that the PAX5/TEL fusion defines the cytogenetic entity dic(9;12)(p13;p13), which accounts for about 1% of childhood ALL, almost exclusively B-progenitor ALL. PAX5/TEL is likely to be an aberrant transcription factor, resulting from joining the 5′ region of PAX5 (a transcription factor essential for B cell development) to the 3′ region of TEL/ETV6, containing the Ets-family DNA binding domain. We have cloned the FLAG-full length chimeric PAX5/TEL cDNA in the retroviral vector pMSCV-IRES-GFP (MigR1) to transduce target cells. We have demonstrated a specific nuclear localization of the chimeric protein in NIH3T3 by immunofluorescence analysis. Moreover, we observed a PAX5/TEL dependent decrease of the cellular growth rate in IL-3 dependent murine proB Ba/F3 cells. We further investigated the function of the PAX5/TEL chimeric protein as a potential oncoprotein in murine preBI cells, as a more physiological model. Murine PAX5 −/− preBI cells and wild type preBI cells were purified as B220+/c-KIT+ cells from mouse fetal liver and they were cultured on OP9 and DL1-OP9 stroma cells in presence of IL-7. The OP9 stroma supports B cell proliferation and survival; the DL1-OP9 stroma expresses Delta-like1, one of the Notch ligands, and it’s important to support T cell development. Both PAX5 −/− preBI cells and wild type preBI cells were transduced with the retroviral construct pMSCV-PAX5/TEL-IRES-GFP to analyze cell proliferation, differentiation and growth-dependence on IL-7. Wild type preBI cells expressing PAX5/TEL showed down modulation of CD19 when cultured on OP9 stroma in presence of IL-7; an inverse correlation was observed between the levels of expression of GFP and of CD19. The down modulation of CD19 can be involved in driving the preBI cell into differentiation block. A possible explanation of CD19 repression can rely on a potential competition between PAX5/TEL and endogenous PAX5 to bind PAX5 consensus region on DNA. On OP9 stroma, PAX5/TEL preBI cells are resistant to TGFbeta anti-proliferative and apoptotic effects, with a three-fold increased growth rate than control cells. Although the specific mechanism of PAX5/TEL disruption of TGFbeta signalling pathway remains to be investigated, we propose the TGFbeta resistance by PAX5/TEL as a way to evade the immunosurveillance. PAX5/TEL-preBI cells cultured on DL1-OP9 showed a different phenotype, with up-regulation of c-KIT and down-regulation of CD44. PAX5−/− preBI cells infected with PAX5TEL and grown on OP9 were CD19 negative even in the presence of PAX5TEL. On DL1-OP9 stroma, PAX5TEL cells were able to differentiate maintaining the developmental plasticity of PAX5 −/− preBI cells. These preliminary results indicate a role of PAX5/TEL as a transcription factor, potentially with a suppressor function, down regulating CD19 expression, thus suggesting a function on B cell differentiation. The chimera is able to interfere with TGFbeta pathway, inducing resistance and conferring an advantage in cell survival, evading the immunosurveillance. PAX5TEL do not replace PAX5 functions in PAX5−/− cells, it cannot activate PAX5 target genes as CD19, important for restoring B cell differentiation. Further analyeis are needed to better evaluate the role of PAX5/TEL protein, both in vivo and in vitro models.





Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3839-3850 ◽  
Author(s):  
K. Briegel ◽  
P. Bartunek ◽  
G. Stengl ◽  
K.C. Lim ◽  
H. Beug ◽  
...  

The tissue-specific transcription factor GATA-1 is a key regulator of red blood cell differentiation. One seemingly contradictory aspect of GATA-1 function is that, while it is abundant in erythroid progenitor cells prior to the onset of overt differentiation, it does not significantly activate known GATA-1 target genes in those cells. To investigate the mechanisms underlying GATA-1 function during the transition from early to late erythropoiesis, we have examined its expression and activity in normal avian erythroid progenitor cells before and after induction of differentiation. In these primary progenitor cells, GATA-1 protein was predominantly located in the cytoplasm, while induction of differentiation caused its rapid relocalization to the nucleus, suggesting that nuclear translocation constitutes an important regulatory step in GATA-1 activation. As an alternative way of addressing the same question, we also ectopically expressed a GATA-1/estrogen receptor fusion protein (GATA-1/ER) in red blood cell progenitors, where nuclear translocation of, and transcriptional activation by, this hybrid factor are conditionally controlled by estrogen. We found that hormone-activated GATA-1/ER protein accelerated red blood cell differentiation, and concomitantly suppressed cell proliferation. These phenotypic effects were accompanied by a simultaneous suppression of c-myb and GATA-2 transcription, two genes thought to be involved in the proliferative capacity of hematopoietic progenitor cells. Thus, GATA-1 appears to promote differentiation in committed erythroid progenitor cells both by inducing differentiation-specific genes and by simultaneously suppressing genes involved in cell proliferation.



1995 ◽  
Vol 128 (6) ◽  
pp. 1197-1208 ◽  
Author(s):  
I Västrik ◽  
A Kaipainen ◽  
T L Penttilä ◽  
A Lymboussakis ◽  
R Alitalo ◽  
...  

Mad is a basic region helix-loop-helix leucine zipper transcription factor which can dimerize with the Max protein and antagonize transcriptional activation by the Myc-Max transcription factor heterodimer. While the expression of Myc is necessary for cell proliferation, the expression of Mad is induced upon differentiation of at least some leukemia cell lines. Here, the expression of the mad gene has been explored in developing mouse tissues. During organogenesis in mouse embryos mad mRNA was predominantly expressed in the liver and in the mantle layer of the developing brain. At later stages mad expression was detected in neuroretina, epidermis, and whisker follicles, and in adult mice mad was expressed at variable levels in most organs analyzed. Interestingly, in the skin mad was highly expressed in the differentiating epidermal keratinocytes, but not in the underlying proliferating basal keratinocyte layer. Also, in the gut mad mRNA was abundant in the intestinal villi, where cells cease proliferation and differentiate, but not in the crypts, where the intestinal epithelial cells proliferate. In the testis, mad expression was associated with the completion of meiosis and early development of haploid cells. In cell culture, Mad inhibited colony formation of a mouse keratinocyte cell line and rat embryo fibroblast transformation by Myc and Ras. The pattern of mad expression in tissues and its ability to inhibit cell growth in vitro suggests that Mad can cause the cessation of cell proliferation associated with cell differentiation in vivo.



Inflammation ◽  
2021 ◽  
Author(s):  
Yang Yang ◽  
Jianhua Xue ◽  
Lili Qin ◽  
Jiaxuan Zhang ◽  
Jiajia Liu ◽  
...  

Abstract Sepsis is considered to be a systemic inflammatory response, which results in organ dysfunction. LncRNA nuclear-enriched abundant transcript 1 (NEAT1) involved in sepsis progression has been reported. However, the underlying mechanism of NEAT1 in sepsis-induced inflammatory response remains to be revealed. In this study, NEAT1 and POU domain class 2 transcription factor 1 (POU2F1) were highly expressed in LPS-induced septic RAW264.7 cells, opposite to miR-31-5p expression. Furthermore, we found that NEAT1 silencing inhibited LPS-induced inflammatory response and cell proliferation, and promoted cell apoptosis. Subsequently, we found that miR-31-5p interacted with NEAT1 and targeted the 3′UTR of POU2F1, and in LPS-induced RAW264.7 cells, the inhibition of NEAT1 silencing was reversed by miR-31-5p knockdown, while POU2F1 downregulation could cover the functions of miR-31-5p knockdown. In a word, this study indicates that NEAT1 inhibits the LPS-induced progression of sepsis in RAW264.7 cells by modulating miR-31-5p/POU2F1 axis, suggesting that NEAT1 will be the potential therapeutic target for sepsis.



2007 ◽  
Vol 157 (suppl_1) ◽  
pp. S3-S14 ◽  
Author(s):  
Daniel Kelberman ◽  
Mehul Tulsidas Dattani

The anterior pituitary gland is a central regulator of growth, reproduction and homeostasis, and is the end-product of a carefully orchestrated pattern of expression of signalling molecules and transcription factors leading to the development of this complex organ secreting six hormones from five different cell types. Naturally occurring and transgenic murine models have demonstrated a role for many of these molecules in the aetiology of combined pituitary hormone deficiency (CPHD). These include the transcription factors HESX1, PROP1, POU1F1, LHX3, LHX4, TBX19, SOX2 and SOX3. The expression pattern of these transcription factors dictates the phenotype that results when the gene encoding the relevant transcription factor is mutated. The highly variable phenotype may consist of isolated hypopituitarism, or more complex disorders such as septo-optic dysplasia and holoprosencephaly. Since mutations in any one transcription factor are uncommon, and since the overall incidence of mutations in known transcription factors is low in patients with CPHD, it is clear that many genes remain to be identified, and the characterization of these will further elucidate the pathogenesis of these complex conditions and also shed light on normal pituitary development.



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