scholarly journals Tissue-specific distribution of a novel C-terminal truncation retinoic acid receptor mutant which acts as a negative repressor in a promoter- and cell-type-specific manner.

1995 ◽  
Vol 15 (4) ◽  
pp. 1961-1967 ◽  
Author(s):  
T Matsui ◽  
S Sashihara
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptor ◽  
Cell Type ◽  
F9 Cells ◽  
Acid Receptor ◽  
Retinoic Acid Response Element ◽  
Specific Distribution ◽  
Mouse Tissues ◽  
Specific Manner ◽  
Cell Type Specific

A cDNA clone which encodes a truncation form of the gamma subtype of the retinoic acid receptor (RAR gamma) has been isolated. The mutant RAR gamma (RAR gamma Bm382) has lost its 65 C-terminal amino acids, thus truncating a part of the dimerization and activation domains. By using a reverse transcription-coupled PCR technique, it was shown that RAR gamma Bm382 is expressed at different levels in various mouse tissues and that the level of its expression does not correlate with that of normal RAR gamma B. Cotransfection studies revealed that RAR gamma Bm382 acts as a repressor of normal RARs in a promoter- and cell-type-specific manner. Transcription of beta RARE and TREinv promoters was inhibited by RAR gamma Bm382 in both HeLa and F9 cells. Unlike these two promoters, however, RAR gamma Bm382 did not inhibit transcription of the TREpal promoter in HeLa cells but did so in F9 cells. Moreover, while transcription of the lamRARE promoter was inhibited by RAR gamma Bm382 in both HeLa and F9 cells, the inhibition was not observed when F9 cells were induced to differentiate with retinoic acid and dibutyryl cyclic AMP. DNA-binding analysis revealed that RAR gamma Bm382 is able to form a heterodimer with the retinoid X receptor and bind to the different types of retinoic acid response elements with almost the same efficiency as normal RAR. By comparison with effects of other truncation mutants created in vitro, it was suggested that the C-terminal end of the ligand binding domain of RAR is crucial for determining the specificity of transactivation by RAR. Given these observations, we discuss the possibility that protein factors which mediate retinoic acid response element- and cell-type-specific transactivation by RAR are present.

scholarly journals Targeted disruption of retinoic acid receptor alpha (RAR alpha) and RAR gamma results in receptor-specific alterations in retinoic acid-mediated differentiation and retinoic acid metabolism.

1995 ◽  
Vol 15 (2) ◽  
pp. 843-851 ◽  
Author(s):  
J F Boylan ◽  
T Lufkin ◽  
C C Achkar ◽  
R Taneja ◽  
P Chambon ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptor ◽  
Specific Gene ◽  
Cell Type ◽  
Targeted Disruption ◽  
F9 Cells ◽  
Retinoid Receptors ◽  
Alpha Gene ◽  
Polar Derivatives ◽  
Crabp Ii

F9 embryonic teratocarcinoma stem cells differentiate into an epithelial cell type called extraembryonic endoderm when treated with retinoic acid (RA), a derivative of retinol (vitamin A). This differentiation is presumably mediated through the actions of retinoid receptors, the RARs and RXRs. To delineate the functions of each of the different retinoid receptors in this model system, we have generated F9 cell lines in which both copies of either the RAR alpha gene or the RAR gamma gene are disrupted by homologous recombination. The absence of RAR alpha is associated with a reduction in the RA-induced expression of both the CRABP-II and Hoxb-1 (formerly 2.9) genes. The absence of RAR gamma is associated with a loss of the RA-inducible expression of the Hoxa-1 (formerly Hox-1.6), Hoxa-3 (formerly Hox-1.5), laminin B1, collagen IV (alpha 1), GATA-4, and BMP-2 genes. Furthermore, the loss of RAR gamma is associated with a reduction in the metabolism of all-trans-RA to more polar derivatives, while the loss of RAR alpha is associated with an increase in metabolism of RA relative to wild-type F9 cells. Thus, each of these RARs exhibits some specificity with respect to the regulation of differentiation-specific gene expression. These results provide an explanation for the expression of multiple RAR types within one cell type and suggest that each RAR has specific functions.

scholarly journals Activation of the phosphoenolpyruvate carboxykinase gene retinoic acid response element is dependent on a retinoic acid receptor/coregulator complex.

1992 ◽  
Vol 12 (12) ◽  
pp. 5527-5535 ◽  
Author(s):  
R K Hall ◽  
D K Scott ◽  
E L Noisin ◽  
P C Lucas ◽  
D K Granner
Keyword(s):  
Retinoic Acid ◽  
Transcriptional Control ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Mutational Analysis ◽  
Retinoic Acid Receptor ◽  
Retinoid Receptor ◽  
Response Element ◽  
Acid Receptor ◽  
Receptor Alpha ◽  
Retinoic Acid Response Element

The accessory factor 1 (AF1) element is an upstream transcriptional control region that plays a role in the response of the phosphoenolpyruvate carboxykinase (PEPCK) gene to both glucocorticoids and retinoic acid. We demonstrate here that retinoic acid receptor alpha (RAR alpha) binds to a sequence within the AF1 element, TGACCT (site B), that is a consensus retinoic acid response element (RARE) half-site. A similar DNA sequence, TGGCCG (site C), located 1 bp downstream of site B, is not involved in the binding of RAR alpha monomers or dimers but is required for the constitution of a functional RARE. Site C is also required for the formation of a complex involving RAR alpha and a liver nuclear factor designated CR, for coregulator. Mutational analysis of the AF1 element shows that the RAR alpha/CR complex is the trans-acting unit that mediates the retinoic acid response of the PEPCK gene. Another member of the retinoid receptor family, retinoid X receptor alpha (RXR alpha), can also form a complex with RAR alpha and the AF1 element. Several observations, including the observation that RXR alpha antibody interacts with CR, indicate that RXR alpha and CR are identical or closely related proteins. Through RXR alpha forms a complex with RAR alpha and the AF1 element, we demonstrate that the AF1 element is functionally distinguishable from a retinoid X response element. Taken together, our results show that the AF1 element contains an RARE that mediates a retinoic acid response by binding an RAR alpha/coregulator complex; this coregulator is presumably RXR alpha.

scholarly journals The t(5;17) variant of acute promyelocytic leukemia expresses a nucleophosmin-retinoic acid receptor fusion

Blood ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 882-886 ◽  
Author(s):  
RL Redner ◽  
EA Rush ◽  
S Faas ◽  
WA Rudert ◽  
SJ Corey
Keyword(s):  
Retinoic Acid ◽  
Acute Promyelocytic Leukemia ◽  
Fusion Proteins ◽  
Fusion Gene ◽  
Retinoic Acid Receptor ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Reading Frame ◽  
Acid Receptor ◽  
Retinoic Acid Response Element

We have studied an acute promyelocytic leukemia (APL) patient with a variant t(5;17)(q32;q12). This translocation fuses the gene for the nucleolar phosphoprotein nucleophosmin (NPM) to the retinoic acid receptor alpha (RARA). Two alternatively spliced transcripts are expressed, which differ in 129 bases immediately upstream of the RARA sequence. The NPM sequences contained in the shorter NPM-RAR cDNA are identical to the NPM sequences contained in the NPM-ALK fusion gene expressed in t(2;5) lymphomas. The RARA sequences are the same as the RARA sequences found in the PML-RAR and PLZF-RAR fusion seen in t(15;17) and t(11;17) APL, respectively. Both NPM-RAR transcripts fuse NPM and RARA sequence in the same reading frame, to generate translation products of 57 kD and 62 kD. Both NPM-RAR proteins are expressed in the patient's leukemic cells, along with wild-type RARA derived from the uninvolved allele. In transcriptional assays using a retinoic acid response element reporter construct, both NPM-RAR fusion proteins act as retinoic acid-dependent transcriptional activators. This case defines a third class of APL rearrangements, all of which generate fusion proteins of RARA.

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