Functional interactions of an upstream enhancer of the mouse glycoprotein hormone α-subunit gene with proximal promoter sequences

1998 ◽  
Vol 142 (1-2) ◽  
pp. 141-152 ◽  
Author(s):  
William M Wood ◽  
Janet M Dowding ◽  
Virginia D Sarapura ◽  
Michael T McDermott ◽  
David F Gordon ◽  
...  
1991 ◽  
Vol 7 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y. Kato ◽  
T. Ezashi ◽  
T. Hirai ◽  
T. Kato

ABSTRACT The gene for the common α subunit of the porcine anterior pituitary glycoprotein hormones was cloned from a genomic library constructed in EMBL3. The nucleotide sequence of the entire coding sequence of the porcine common α-subunit gene was determined in addition to one intron and 1059 and 160 bp of the 5′-and 3′-flanking regions respectively. Southern blot analysis of the porcine genomic DNA indicated that the common α-subunit gene is present as a single copy. The transcriptional unit of the porcine common α subunit spanned about 14kb and contained four exons interrupted by three introns of about 11.5, 1.2 and 0.4kb. The short untranslated sequence in the first exon and the location of the exon/intron junctions at amino acid residues +9/+10 and +71/+72 were highly conserved among the rat, human and bovine common α-subunit genes. In the proximal portion of the 5′-flanking region, one TATA box and one CCAAT box were present. A steroid-responsive element was not found up to 1059 bases upstream from the transcription start site. The potential AP-1 and AP-2 factor-responsive elements were present at three and one positions respectively in the 5′-flanking region. This feature suggests that hypothalamic gonadotrophin-releasing hormone stimulates the expression of the common α-subunit gene predominantly by a signal-transduction system, with the protein kinase C cascade and factors AP-1 and AP-2 as mediators. The cyclic AMP-responsive element was also present at two positions, but a single base substitution was found in each sequence compared with the consensus sequence. The porcine common α-subunit gene has a structure distinct from its counterparts, the porcine FSH-β and LH-β genes, reflecting differential control of their synthesis during gametogenesis.


1990 ◽  
Vol 4 (10) ◽  
pp. 1480-1487 ◽  
Author(s):  
Robert A. Fenstermaker ◽  
Todd A. Farmerie ◽  
Colin M. Clay ◽  
Debora L. Hamernik ◽  
John H. Nilson

1990 ◽  
Vol 4 (4) ◽  
pp. 573-582 ◽  
Author(s):  
Bogi Andersen ◽  
Giulia Catignani Kennedy ◽  
Debora L. Hamernik ◽  
Joseph A. Bokar ◽  
Robert Bohinski ◽  
...  

2000 ◽  
Vol 20 (10) ◽  
pp. 3331-3344 ◽  
Author(s):  
Mark S. Roberson ◽  
Makiko Ban ◽  
Tong Zhang ◽  
Jennifer M. Mulvaney

ABSTRACT The aim of these studies was to elucidate a role for epidermal growth factor (EGF) signaling in the transcriptional regulation of the glycoprotein hormone α subunit gene, a subunit of chorionic gonadotropin. Studies examined the effects of EGF and the adenylate cyclase activator forskolin on the expression of a transfected α subunit reporter gene in a human choriocarcinoma cell line (JEG3). At maximal doses, administration of EGF resulted in a 50% increase in a subunit reporter activity; forskolin administration induced a fivefold activation; the combined actions of EGF and forskolin resulted in synergistic activation (greater than eightfold) of the α subunit reporter. Mutagenesis studies revealed that the cyclic AMP response elements (CRE) were required and sufficient to mediate EGF-forskolin-induced synergistic activation. The combined actions of EGF and forskolin resulted in potentiated activation of extracellular signal-regulated kinase (ERK) enzyme activity compared with EGF alone. Specific blockade of ERK activation was sufficient to block EGF-forskolin-induced synergistic activation of the α subunit reporter. Pretreatment of JEG3 cells with a p38 mitogen-activated protein kinase inhibitor did not influence activation of the α reporter. However, overexpression of c-Jun N-terminal kinase (JNK)-interacting protein 1 as a dominant interfering molecule abolished the synergistic effects of EGF and forskolin on the α subunit reporter. CRE binding studies suggested that the CRE complex consisted of CRE binding protein and EGF-ERK-dependent recruitment of c-Jun–c-Fos (AP-1) to the CRE. A dominant negative form of c-Fos (A-Fos) that specifically disrupts c-Jun–c-Fos DNA binding inhibited synergistic activation of the α subunit. Thus, synergistic activation of the α subunit gene induced by EGF-forskolin requires the ERK and JNK cascades and the recruitment of AP-1 to the CRE binding complex.


Endocrinology ◽  
1990 ◽  
Vol 127 (3) ◽  
pp. 1352-1361 ◽  
Author(s):  
VIRGINIA D. SARAPURA ◽  
WILLIAM M. WOOD ◽  
DAVID F. GORDON ◽  
KENNETH W. OCRAN ◽  
MARILEE Y. KAO ◽  
...  

1998 ◽  
Vol 12 (5) ◽  
pp. 622-633 ◽  
Author(s):  
Michelle L. Brinkmeier ◽  
David F. Gordon ◽  
Janet M. Dowding ◽  
Thomas L. Saunders ◽  
Susan K. Kendall ◽  
...  

Abstract The glycoprotein hormone α-subunit gene is expressed and differentially regulated in pituitary gonadotropes and thyrotropes. Previous gene expression studies suggested that cell specificity may be regulated by distinct DNA elements. We have identified an enhancer region between −4.6 and −3.7 kb that is critical for high level expression in both gonadotrope and thyrotrope cells of transgenic mice. Fusion of the enhancer to −341/+43 mouseα -subunit promoter results in appropriate pituitary cell specificity and transgene expression levels that are similar to levels observed with the intact −4.6 kb/+43 construct. Deletion of sequences between− 341 and −297 resulted in a loss of high level expression and cell specificity, exhibited by ectopic transgene activation in GH-, ACTH-, and PRL-producing pituitary cells as well as in other peripheral tissues. Consistent with these results, transient cell transfection studies demonstrated that the enhancer stimulated activity of a− 341/+43 α-promoter in both αTSH and αT3 cells, but it did not enhance α-promoter activity significantly in CV-1 cells. Removal of sequences between −341 and −297 allowed the enhancer to function in heterologous cells. Loss of high level expression and cell specificity may be due to loss of sequences required for binding of the LIM homeoproteins or the α-basal element 1. These data demonstrate that the enhancer requires participation by both proximal and distal sequences for high level expression and suggests that sequences from− 341 to −297 are critical for restricting expression to the anterior pituitary.


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