Cofactor CLIM2 promotes the repressive action of LIM homeodomain transcription factor Lhx2 in the expression of porcine pituitary glycoprotein hormone α subunit gene

2006 ◽  
Vol 1759 (8-9) ◽  
pp. 403-409 ◽  
Author(s):  
Takao Susa ◽  
Takanobu Sato ◽  
Tetsuo Ono ◽  
Takako Kato ◽  
Yukio Kato
Keyword(s):  
Transcription Factor ◽  
Subunit Gene ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Homeodomain Transcription Factor ◽  
Lim Homeodomain

scholarly journals Activation of the Thyroid-Stimulating Hormone β-Subunit Gene by LIM Homeodomain Transcription Factor Lhx2

Endocrinology ◽  
2007 ◽  
Vol 148 (7) ◽  
pp. 3468-3476 ◽  
Author(s):  
Kee K. Kim ◽  
Seok B. Song ◽  
Kwang I. Kang ◽  
Myungchull Rhee ◽  
Kyoon Eon Kim
Keyword(s):  
Transcription Factor ◽  
Reporter Gene ◽  
Thyroid Stimulating Hormone ◽  
Β Subunit ◽  
Subunit Gene ◽  
Mobility Shift ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Homeodomain Transcription Factor ◽  
Lim Homeodomain

Although there is evidence that the LIM homeodomain transcription factor, Lhx2, can stimulate transcription of the glycoprotein hormone α-subunit gene, the role of Lhx2 in regulating TSH β-subunit has not been established. In the present studies, the ability of Lhx2 to regulate transcription of the TSH β-subunit gene was examined. In the thyrotrope-derived TαT1 cell line, Lhx2 expression was found to be induced by treatment with either TRH or cAMP, consistent with the possibility that Lhx2 may play a role in mediating the ability of this signaling pathway to stimulate TSH gene expression. Transient, forced overexpression of Lhx2 stimulated activity of a TSH β-subunit reporter gene. Deletion studies provided evidence that the −177 to −79 region of the TSH β-subunit promoter was necessary for stimulation of reporter gene activity by Lhx2. A gel mobility shift assay provided the evidence that Lhx2 can bind to this region of DNA. DNase I footprinting studies demonstrated that two distinct regions of the TSHβ promoter, −118 to −108 and −86 to −68, are protected by Lhx2 from nuclease digestion. These regions contain repeats of the sequence, 5′-(G/T)CAAT(T/A)-3′. Mutation of this sequence, especially in the −86 to −68 region, substantially decreased Lhx2 responsiveness of the TSH β-subunit reporter gene. In addition, a DNA fragment containing the −177 to −79 region of the TSHβ promoter was found to confer Lhx2 responsiveness to a minimal promoter. These results provide multiple lines of evidence consistent with a role for Lhx2 in modulating expression of the TSH β-subunit gene.

scholarly journals Activation of the glycoprotein hormone alpha-subunit promoter by a LIM-homeodomain transcription factor.

1994 ◽  
Vol 14 (5) ◽  
pp. 2985-2993 ◽  
Author(s):  
M S Roberson ◽  
W E Schoderbek ◽  
G Tremml ◽  
R A Maurer
Keyword(s):  
Transcription Factor ◽  
Binding Activity ◽  
Alpha Subunit ◽  
Homeodomain Protein ◽  
Pituitary Cells ◽  
Glycoprotein Hormone ◽  
Homeodomain Transcription Factor ◽  
Imperfect Palindrome ◽  
Recombinant Lh ◽  
Lim Homeodomain

Recently, a pituitary-specific enhancer was identified within the 5' flanking region of the mouse glycoprotein hormone alpha-subunit gene. This enhancer is active in pituitary cells of the gonadotrope and thyrotrope lineages and has been designated the pituitary glycoprotein hormone basal element (PGBE). In the present studies, we sought to isolate and characterize proteins which interact with the PGBE. Mutagenesis experiments identified a 14-bp imperfect palindrome that is required for binding of a factor which is present in cells of gonadotrope and thyrotrope lineages but not in other cells. Screening of a mouse cDNA library with a DNA probe containing the imperfect palindrome resulted in the isolation of a LIM-homeodomain transcription factor. The cDNA predicts a mouse protein which is 94% identical to the recently described rat LIM-homeodomain protein LH-2. LH-2 contains two zinc fingers (LIM domain) and a consensus homeodomain. Hybridization analysis revealed relatively high expression of LH-2 mRNA in the central nervous system and in pituitary cells of the gonadotrope and thyrotrope lineages. Lower or nondetectable levels of LH-2 mRNA were found in other pituitary cells and tissues, including placental cells. Recombinant LH-2 homeodomain was found to selectively bind to the previously identified imperfect palindrome in the PGBE. Point mutations in the PGBE resulted in parallel losses in the binding of a nuclear factor from a cell line of the gonadotrope lineage and recombinant LH-2-binding activity. Use of an antibody to LH-2 provided evidence that endogenous PGBE-binding activity from cells of the gonadotrope lineage involves a protein which is immunologically related to LH-2. Expression of LH-2 in two heterologous cell types resulted in activation of a reporter gene containing the mouse alpha promoter. These data suggest that the LIM-homeodomain factor LH-2 plays a role in stimulating tissue-specific expression of the mouse glycoprotein hormone alpha subunit. The finding that a LIM-homeodomain protein can stimulate expression of one of the earliest markers of pituitary differentiation raises the possibility that this factor plays a role in cell lineage determination in the pituitary.

Activation of the glycoprotein hormone alpha-subunit promoter by a LIM-homeodomain transcription factor

1994 ◽  
Vol 14 (5) ◽  
pp. 2985-2993
Author(s):  
M S Roberson ◽  
W E Schoderbek ◽  
G Tremml ◽  
R A Maurer
Keyword(s):  
Transcription Factor ◽  
Binding Activity ◽  
Alpha Subunit ◽  
Homeodomain Protein ◽  
Pituitary Cells ◽  
Glycoprotein Hormone ◽  
Homeodomain Transcription Factor ◽  
Imperfect Palindrome ◽  
Recombinant Lh ◽  
Lim Homeodomain

Recently, a pituitary-specific enhancer was identified within the 5' flanking region of the mouse glycoprotein hormone alpha-subunit gene. This enhancer is active in pituitary cells of the gonadotrope and thyrotrope lineages and has been designated the pituitary glycoprotein hormone basal element (PGBE). In the present studies, we sought to isolate and characterize proteins which interact with the PGBE. Mutagenesis experiments identified a 14-bp imperfect palindrome that is required for binding of a factor which is present in cells of gonadotrope and thyrotrope lineages but not in other cells. Screening of a mouse cDNA library with a DNA probe containing the imperfect palindrome resulted in the isolation of a LIM-homeodomain transcription factor. The cDNA predicts a mouse protein which is 94% identical to the recently described rat LIM-homeodomain protein LH-2. LH-2 contains two zinc fingers (LIM domain) and a consensus homeodomain. Hybridization analysis revealed relatively high expression of LH-2 mRNA in the central nervous system and in pituitary cells of the gonadotrope and thyrotrope lineages. Lower or nondetectable levels of LH-2 mRNA were found in other pituitary cells and tissues, including placental cells. Recombinant LH-2 homeodomain was found to selectively bind to the previously identified imperfect palindrome in the PGBE. Point mutations in the PGBE resulted in parallel losses in the binding of a nuclear factor from a cell line of the gonadotrope lineage and recombinant LH-2-binding activity. Use of an antibody to LH-2 provided evidence that endogenous PGBE-binding activity from cells of the gonadotrope lineage involves a protein which is immunologically related to LH-2. Expression of LH-2 in two heterologous cell types resulted in activation of a reporter gene containing the mouse alpha promoter. These data suggest that the LIM-homeodomain factor LH-2 plays a role in stimulating tissue-specific expression of the mouse glycoprotein hormone alpha subunit. The finding that a LIM-homeodomain protein can stimulate expression of one of the earliest markers of pituitary differentiation raises the possibility that this factor plays a role in cell lineage determination in the pituitary.

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 ◽  
...  
Keyword(s):  
Proximal Promoter ◽  
Subunit Gene ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Promoter Sequences ◽  
Functional Interactions

scholarly journals Regulation of Porcine Pituitary Glycoprotein Hormone Alpha Subunit Gene with LIM-Homeobox Transcription Factor Lhx3

2009 ◽  
Vol 55 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Takao SUSA ◽  
Akio ISHIKAWA ◽  
Takako KATO ◽  
Michie NAKAYAMA ◽  
Kousuke KITAHARA ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Alpha Subunit ◽  
Subunit Gene ◽  
Glycoprotein Hormone ◽  
Homeobox Transcription Factor

The gene for the common α subunit of porcine pituitary glycoprotein hormone

1991 ◽  
Vol 7 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y. Kato ◽  
T. Ezashi ◽  
T. Hirai ◽  
T. Kato
Keyword(s):  
Genomic Library ◽  
Consensus Sequence ◽  
Transcriptional Unit ◽  
Base Substitution ◽  
Subunit Gene ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
The Common ◽  
Flanking Region ◽  
Responsive Element

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.

scholarly journals Pituitary transcription factor Prop-1 stimulates porcine pituitary glycoprotein hormone α subunit gene expression

2006 ◽  
Vol 37 (2) ◽  
pp. 341-352 ◽  
Author(s):  
Takanobu Sato ◽  
Kousuke Kitahara ◽  
Takao Susa ◽  
Takako Kato ◽  
Yukio Kato
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Binding Sites ◽  
Gh3 Cells ◽  
Pituitary Hormone ◽  
Transcriptional Level ◽  
Β Subunit ◽  
Glycoprotein Hormone ◽  
Α Subunit

Recently, we have reported that a Prophet of Pit-1 homeodomain factor, Prop-1, is a novel transcription factor for the porcine follicle-stimulating hormone β subunit (FSHβ) gene. This study subsequently aimed to examine the role of Prop-1 in the gene expression of two other porcine gonadotropin subunits, pituitary glycoprotein hormone α subunit (αGSU), and luteinizing hormone β subunit (LHβ). A series of deletion mutants of the porcine αGSU (up to −1059 bp) and LHβ (up to −1277 bp) promoters were constructed in the reporter vector, fused with the secreted alkaline phosphatase gene (pSEAP2-Basic). Transient transfection studies using GH3 cells were carried out to estimate the activation of the porcine αGSU and LHβ promoters by Prop-1, which was found to activate the αGSU promoter of −1059/+12 bp up to 11.7-fold but not the LHβ promoter. Electrophoretic mobility shift assay and DNase I footprinting analysis revealed that Prop-1 binds to six positions, −1038/−1026, −942/−928, −495/−479, −338/−326, −153/−146, and −131/−124 bp, that comprise the A/T cluster. Oligonucleotides of six Prop-1 binding sites were directly connected to the minimum promoter of αGSU, fused in the pSEAP2-Basic vector, followed by transfecting GH3 cells to determine the cis-acting activity. Finally, we concluded that at least five Prop-1 binding sites are the cis-acting elements for αGSU gene expression. The present results revealed a notable feature of the proximal region, where three Prop-1-binding sites are close to and/or overlap the pituitary glycoprotein hormone basal element, GATA-binding element, and junctional regulatory element. To our knowledge, this is the first demonstration of the role of Prop-1 in the regulation of αGSU gene expression. These results, taken together with our previous finding that Prop-1 is a transcription factor for FSHβ gene, confirm that Prop-1 modulates the synthesis of FSH at the transcriptional level. On the other hand, the defects of Prop-1 are known to cause dwarfism and combined pituitary hormone deficiency accompanying hypogonadism. Accordingly, the present observations provide a novel view to understand the hypogonadism caused by Prop-1 defects at the molecular level through the regulatory mechanism of αGSU and FSHβ gene expressions.

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