scholarly journals The LIM-Homeodomain Proteins Isl-1 and Lhx3 Act with Steroidogenic Factor 1 to Enhance Gonadotrope-Specific Activity of the Gonadotropin-Releasing Hormone Receptor Gene Promoter

2006 ◽  
Vol 20 (9) ◽  
pp. 2093-2108 ◽  
Author(s):  
Anne Granger ◽  
Christian Bleux ◽  
Marie-Laure Kottler ◽  
Simon J. Rhodes ◽  
Raymond Counis ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Specific Activity ◽  
Receptor Gene ◽  
Marker Gene ◽  
Gene Promoter ◽  
Dominant Negative ◽  
R Gene ◽  
Specific Expression ◽  
Steroidogenic Factor 1 ◽  
Lim Homeodomain

Abstract The GnRH receptor (GnRH-R) plays a central role in mammalian reproductive function throughout adulthood. It also appears as an early marker gene of the presumptive gonadotrope lineage in developing pituitary. Here, using transient transfections combined with DNA/protein interaction assays, we have delineated cis-acting elements within the rat GnRH-R gene promoter that represent targets for the LIM-homeodomain (LIM-HD) proteins, Isl-1 and Lhx3. These factors, critical in early pituitary development, are thus also crucial for gonadotrope-specific expression of the GnRH-R gene. In heterologous cells, the expression of Isl-1 and Lhx3, together with steroidogenic factor 1 (SF-1), culminates in the activation of both the rat as well as human GnRH-R promoter, suggesting that this combination is evolutionarily conserved among mammals. The specificity of these LIM-HD factors is attested by the inefficiency of related proteins, including Lhx5 and Lhx9, to activate the GnRH-R gene promoter, as well as by the repressive capacity of a dominant-negative derivative of Lhx3. Accordingly, targeted deletion of the LIM response element decreases promoter activity. In addition, experiments with Gal4-SF-1 fusion proteins suggest that LIM-HD protein activity in gonadotrope cells is dependent upon SF-1 binding. Finally, using a transgenic model that allows monitoring of in vivo promoter activity, we show that the overlapping expression of Isl-1 and Lhx3 in the developing pituitary correlates with promoter activity. Collectively, these data suggest the occurrence of a specific LIM-HD pituitary code and designate the GnRH-R gene as the first identified transcriptional target of Isl-1 in the anterior pituitary.

scholarly journals Proximal cis-Acting Elements, Including Steroidogenic Factor 1, Mediate the Efficiency of a Distal Enhancer in the Promoter of the Rat Gonadotropin-Releasing Hormone Receptor Gene

2001 ◽  
Vol 15 (2) ◽  
pp. 319-337 ◽  
Author(s):  
Hanna Pincas ◽  
Karine Amoyel ◽  
Raymond Counis ◽  
Jean-Noël Laverrière
Keyword(s):  
Target Genes ◽  
Receptor Gene ◽  
Proximal Region ◽  
R Gene ◽  
Distal Enhancer ◽  
Mobility Shift ◽  
Related Factors ◽  
Specific Expression ◽  
Enhancer Activity ◽  
Steroidogenic Factor 1

Abstract The gonadotrope-specific and regulated expression of the GnRH receptor (GnRH-R) gene is dependent on multiple transcription factors that interact with the noncanonical GnRH-R activating sequence (GRAS), the activator protein-1 (AP-1) element, and the steroidogenic factor-1 (SF-1) binding site. However, these three elements are not sufficient to mediate the complete cell-specific expression of the rat GnRH-R gene. In the present study, we demonstrate, by transient transfection in gonadotrope-derived αT3–1 and LβT2 cell lines, the existence of a distal enhancer [GnRH-R- specific enhancer (GnSE)] that is highly active in the context of the GnRH-R gene promoter. We show that the GnSE activity (–1,135/–753) is mediated through a functional interaction with a proximal region (–275/–226) that includes the SF-1 response element. Regions of similar length containing either the AP-1 or GRAS elements are less active or inactive. Transfection assays using an artificial promoter containing two SF-1 elements fused to a minimal PRL promoter indicate that SF-1 is crucial in this interaction. In addition, by altering the promoter with deletion and block- replacement mutations, we have identified the active elements of GnSE within two distinct sequences at positions –983/–962 and –871/–862. Sequence analysis and electrophoretic mobility shift experiments suggest that GnSE response elements interact, in these two regions, with GATA- and LIM-related factors, respectively. Altogether, these data establish the importance of the GnSE in the GnRH-R gene expression and reveal a novel role for SF-1 as a mediator of enhancer activity, a mechanism that might regulate other SF-1 target genes.

scholarly journals GATA2-Induced Silencing and LIM-Homeodomain Protein-Induced Activation Are Mediated by a Bi-Functional Response Element in the Rat GnRH Receptor Gene

2013 ◽  
Vol 27 (1) ◽  
pp. 74-91 ◽  
Author(s):  
Anne-Laure Schang ◽  
Anne Granger ◽  
Bruno Quérat ◽  
Christian Bleux ◽  
Joëlle Cohen-Tannoudji ◽  
...  
Keyword(s):  
Cell Fate ◽  
Promoter Activity ◽  
Receptor Gene ◽  
Gnrh Receptor ◽  
Expression Vectors ◽  
Homeodomain Protein ◽  
Homeodomain Proteins ◽  
Enhancer Activity ◽  
Response Element ◽  
Lim Homeodomain

GATA2 transcription factor and LIM homeodomain proteins Islet1 (ISL1) and LIM homeobox 3 (LHX3) are suspected to be involved in gonadotrope cell fate and maintenance. The GnRH receptor gene (Gnrhr), crucial for gonadotrope function, is expressed in the pituitary gland from embryonic day 13.5 onward, well before LH and FSH β-subunits. This expression pattern together with the presence of WGATAR and TAAT motifs in Gnrhr promoter sequences suggests the involvement of early transcription factors in promoter activation. In this study, using a well-characterized transgenic mouse model, GATA2 was found colocalized with Gnrhr promoter activity in the pituitary. Transient transfection of Gnrhr promoter luciferase fusion constructs together with either GATA2 expression vectors or small interfering RNA in gonadotrope cell lines indicated that GATA2, which typically acts as a trans-activator, unexpectedly repressed Gnrhr promoter activity. Using DNA chromatography affinity and EMSA, we demonstrated that GATA2 operates via a response element containing a peculiar palindromic GATA motif that overlaps a critical TAAT motif involved in LHX3/ISL1 trans-activation. Indeed, despite the inhibitory action of GATA2, this element displayed a clear-cut enhancer activity in gonadotrope cells. Chromatin immunoprecipitation assays indicated that GATA2, LHX3, and ISL1 interact with a Gnrhr promoter fragment encompassing this element. The trans-repressive action of GATA2 on Gnrhr promoter activity is likely balanced or even hindered by trans-activating effects of LIM homeodomain proteins via this novel bifunctional LIM/GATA response element. Such a hierarchical interplay may contribute to finely adjust Gnrhr gene expression in gonadotrope cell lineage during pituitary development as well as in the adult animal.

Identification and Analysis of Two Novel Sites of Rat GnRH Receptor Gene Promoter Activity: The Pineal Gland and Retina

2012 ◽  
Vol 97 (2) ◽  
pp. 115-131 ◽  
Author(s):  
Anne-Laure Schang ◽  
Christian Bleux ◽  
Marie-Claude Chenut ◽  
Valérie Ngô-Muller ◽  
Bruno Quérat ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Promoter Activity ◽  
Receptor Gene ◽  
Gene Promoter ◽  
Gnrh Receptor

scholarly journals Hypoxic activation of the atrial natriuretic peptide gene promoter through direct and indirect actions of hypoxia-inducible factor-1

2003 ◽  
Vol 370 (1) ◽  
pp. 149-157 ◽  
Author(s):  
Yang-Sook CHUN ◽  
Ju-Yeon HYUN ◽  
Yong-Geun KWAK ◽  
In-San KIM ◽  
Chan-Hyung KIM ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Promoter Activity ◽  
Hypoxia Inducible Factor ◽  
Gene Promoter ◽  
Ventricular Myocardium ◽  
Dominant Negative ◽  
Hypoxia Inducible Factor 1 ◽  
Binding Sequence ◽  
Atrial Natriuretic

Atrial natriuretic peptide (ANP) is a cardiac peptide, the transcription of which is up-regulated in the ischaemic ventricle. However, the molecular mechanism of ANP induction is unclear. This study demonstrated that ANP mRNA expression in rat ventricular myocardium is induced in an early phase of ischaemia, preceded by hypoxia-inducible factor-1 (HIF-1) α expression. The ANP gene was also induced by hypoxia or HIF-1 inducers such as CoCl2 and desferrioxamine in H9c2 and neonatal cardiomyocytes. The 2307bp 5′-flanking region of the rat ANP gene was cloned and fused to the luciferase gene. Evidence of the promoter activity was only apparent in the myocytes and was induced by hypoxia and HIF-1 inducers. The overexpression of HIF-1α markedly enhanced ANP promoter activity, and a dominant-negative isoform completely suppressed it. We demonstrated that the promoter regions are essential for hypoxic ANP induction. One promoter region, containing the HIF-1-binding sequence, is regulated directly by HIF-1. The other region is also activated by HIF-1 despite having no HIF-1-binding sequence. These results suggest that HIF-1 enhances the transactivation of the ANP gene in hypoxic myocytes, implying that stimulation of the ANP promoter by HIF-1 may in fact be responsible for the induction of the ANP gene in ischaemic ventricular myocardium.

scholarly journals Transcriptional and posttranscriptional regulation of the expression of the erythropoietin receptor gene in human erythropoietin-responsive cell lines

Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3760-3769 ◽  
Author(s):  
AR Migliaccio ◽  
Y Jiang ◽  
G Migliaccio ◽  
S Nicolis ◽  
S Crotta ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Lines ◽  
Gene Transcription ◽  
Receptor Gene ◽  
Erythropoietin Receptor ◽  
Tumor Promoter ◽  
Target Cells ◽  
R Gene ◽  
Specific Expression ◽  
Responsive Cell

Abstract With erythroid differentiation, committed progenitor cells acquire the ability to respond to erythropoietin (Epo). Epo interacts with target cells through the Epo receptor (Epo-R), whose expression is tightly regulated in a lineage-specific fashion. Epo-R expression is presumed to be progressively activated or repressed as cells progress along the erythroid or the myeloid pathway, respectively. Little is known of the mechanisms that underlie the erythroid-specific expression of the Epo-R gene. GATA-1, the major known transcription factor involved in Epo-R gene regulation, is not erythroid-specific. We have studied the regulation of the expression of the Epo-R gene in two related human Epo- responsive cell lines, UT-7 and UT-7 Epo. These lines express Epo-R at high levels because of amplification of the endogenous gene, which is apparently not rearranged. Treatment for 6 to 24 hours with the tumor promoter, phorbol myristate acetate (PMA), or 24 hours of growth factor starvation (Epo or granulocyte/macrophage colony-stimulating factor [GM- CSF]) decreased or increased the levels of Epo-R mRNA, respectively. In the case of growth factor starvation, the increase (approximately equal to threefold) in the level of Epo-R mRNA correlated directly with an increase in the rate of Epo-R gene transcription as measured by run-off assay. Both increases were observed as early as 3 hours after the growth factor was withdrawn and were reversible; levels of mRNA and transcription rates returned to baseline 3 hours after the cells were reexposed to growth factors. The changes in Epo-R expression after growth factor starvation were coordinated with changes in the level of expression of GATA-1 that were detected both at the mRNA and at the gene transcription level under these conditions (suggesting that GATA-1 was responsible for this upregulation). During PMA treatment, after a transient increase in Epo-R mRNA at 1 hour, a progressive decline in the level of Epo-R mRNA was observed; the level of Epo-R mRNA decreased by 50%, and fell below the level of detection by 6 and 24 hours, respectively. This decrement was explained in part by a fourfold reduction in the rate of gene transcription as well as a reduction (measured as levels of Epo-R mRNA in the presence of actinomycin D) in mRNA stability. The changes in transcription rate occurred in the absence of changes in the level of GATA-1 binding activity.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Identification of an Embryonic Cell-Specific Region within the Pineapple SERK1 Promoter

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 883 ◽  
Author(s):  
Luan ◽  
He ◽  
Xie ◽  
Chen ◽  
Mao ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
Transcription Initiation ◽  
Promoter Activity ◽  
Specific Activity ◽  
Marker Gene ◽  
Immature Embryo ◽  
Embryonic Cell ◽  
Regulatory Sequence ◽  
Regulatory Sequences ◽  
Embryonic Callus

Plant tissue culture methods, such as somatic embryogenesis, are attractive alternatives to traditional breeding methods for plant propagation. However, they often suffer from limited efficiency. Somatic embryogenesis receptor kinase (SERK)1 is a marker gene of early somatic embryogenesis in several plants, including pineapple. It can be selectively induced and promotes a key step in somatic embryogenesis. We investigated the embryonic cell-specific transcriptional regulation of AcSERK1 by constructing a series of vectors carrying the GUS（Beta-glucuronidase） reporter gene under the control of different candidate cis-regulatory sequences. These vectors were transfected into both embryonic and non-embryonic callus, and three immature embryo stages and the embryonic-specific activity of the promoter fragments was analyzed. We found that the activity of the regulatory sequence of AcSERK1 lacking −983 nt ~−880 nt, which included the transcription initiation site, was significantly reduced in the embryonic callus of pineapple, accompanied by the loss of embryonic cell-specific promoter activity. Thus, this fragment is an essential functional segment with highly specific promoter activity for embryonic cells, and it is active only from the early stages of somatic embryo development to the globular embryo stage. This study lays the foundation for identifying mechanisms that enhance the efficiency of somatic embryogenesis in pineapple and other plants.

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