scholarly journals Identification and characterization of a functional retinoic acid/thyroid hormone-response element upstream of the human insulin gene enhancer

1995 ◽  
Vol 309 (3) ◽  
pp. 863-870 ◽  
Author(s):  
A R Clark ◽  
M E Wilson ◽  
N J M London ◽  
R F L James ◽  
K Docherty
Keyword(s):  
Retinoic Acid ◽  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Nuclear Hormone Receptor ◽  
Insulin Gene ◽  
Acid Receptor ◽  
Trans Retinoic Acid ◽  
Human Insulin Gene ◽  
All Trans Retinoic Acid

A deletion analysis of the human insulin gene extending to 2 kb upstream of the transcription start site provided evidence of regulatory sequences located upstream of the insulin-linked polymorphic region (ILPR). Within this ILPR-distal region is a sequence (Ink, for insulin kilobase upstream) which contains three potential nuclear hormone-receptor half-sites, closely matching the consensus sequence AGGTCA. These sequences are arranged as a palindromic element with zero spacing over-lapping a direct repeat with 2 bp spacing. The Ink sequence was used in electrophoretic mobility-shift assays within nuclear extracts from COS-7 cells overexpressing the vitamin D, thyroid hormone or retinoic acid receptors, or from an insulin-expressing hamster cell line, HIT-T15. These studies suggest that the insulin-expressing cell line contains thyroid hormone and retinoic acid receptors at least, and that these receptors are able to recognize the Ink sequence. Three copies of the Ink sequence were placed upstream of the thymidine kinase promoter and firefly luciferase reporter gene. In COS-7 cells expressing the appropriate nuclear hormone receptor, this construct was responsive to both thyroid hormone (18-fold) and all-trans-retinoic acid (31-fold). In HIT-T15 cells the same construct responded to all-trans-retinoic acid, but not to thyroid hormone. Within the context of a 2 kb insulin gene fragment, the Ink sequence was shown to be activated by retinoic acid and by the retinoic acid receptor, but acted as a negative element in the presence of both retinoic acid and the retinoic acid receptor. Mutagenesis studies demonstrated that the palindromic sequence was important for the retinoic acid response, and for binding of complexes containing retinoic acid receptor. In human islets of Langerhans, retinoic acid was shown to stimulate insulin mRNA levels. These results demonstrate that a functional nuclear hormone-receptor-response element is located upstream of the human ILPR. As retinoic acid and thyroid hormone are frequently involved in developmental regulatory processes, it is possible that this element may be important in the process of islet cell differentiation.

scholarly journals A new orphan member of the nuclear hormone receptor superfamily that interacts with a subset of retinoic acid response elements.

1994 ◽  
Vol 14 (3) ◽  
pp. 1544-1552 ◽  
Author(s):  
M Baes ◽  
T Gulick ◽  
H S Choi ◽  
M G Martinoli ◽  
D Simha ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Direct Repeat ◽  
Nuclear Hormone Receptor ◽  
Response Elements ◽  
Acid Receptor ◽  
Hormone Response Elements ◽  
All Trans Retinoic Acid ◽  
Receptor Beta

We have identified and characterized a new orphan member of the nuclear hormone receptor superfamily, called MB67, which is predominantly expressed in liver. MB67 binds and transactivates the retinoic acid response elements that control expression of the retinoic acid receptor beta 2 and alcohol dehydrogenase 3 genes, both of which consist of a direct repeat hexamers related to the consensus AGGTCA, separated by 5 bp. MB67 binds these elements as a heterodimer with the 9-cis-retinoic acid receptor, RXR. However, MB67 does not bind or activate other retinoic acid response elements with alternative hexamer arrangements or any of several other wild-type and synthetic hormone response elements examined. The transactivation of retinoic acid response elements by MB67 is weaker than that conferred by the retinoic acid receptors but does not require the presence of all-trans retinoic acid, 9-cis-retinoic acid, or any exogenously added ligand. We propose that MB67 plays an important role in the complex network of proteins that govern response to retinoic acid and its metabolites.

scholarly journals A new orphan member of the nuclear hormone receptor superfamily that interacts with a subset of retinoic acid response elements

1994 ◽  
Vol 14 (3) ◽  
pp. 1544-1552
Author(s):  
M Baes ◽  
T Gulick ◽  
H S Choi ◽  
M G Martinoli ◽  
D Simha ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Direct Repeat ◽  
Nuclear Hormone Receptor ◽  
Response Elements ◽  
Acid Receptor ◽  
Hormone Response Elements ◽  
All Trans Retinoic Acid ◽  
Receptor Beta

We have identified and characterized a new orphan member of the nuclear hormone receptor superfamily, called MB67, which is predominantly expressed in liver. MB67 binds and transactivates the retinoic acid response elements that control expression of the retinoic acid receptor beta 2 and alcohol dehydrogenase 3 genes, both of which consist of a direct repeat hexamers related to the consensus AGGTCA, separated by 5 bp. MB67 binds these elements as a heterodimer with the 9-cis-retinoic acid receptor, RXR. However, MB67 does not bind or activate other retinoic acid response elements with alternative hexamer arrangements or any of several other wild-type and synthetic hormone response elements examined. The transactivation of retinoic acid response elements by MB67 is weaker than that conferred by the retinoic acid receptors but does not require the presence of all-trans retinoic acid, 9-cis-retinoic acid, or any exogenously added ligand. We propose that MB67 plays an important role in the complex network of proteins that govern response to retinoic acid and its metabolites.

Expression of human all-trans-retinoic acid receptor β and its ligand-binding domain in Escherichia coli

1995 ◽  
Vol 308 (1) ◽  
pp. 353-359 ◽  
Author(s):  
M Berggren Söderlund ◽  
G Johannesson ◽  
G Fex
Keyword(s):  
Escherichia Coli ◽  
Retinoic Acid ◽  
Ligand Binding ◽  
Retinoic Acid Receptor ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Acid Receptor ◽  
Recombinant Receptors ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid

all-trans-Retinoic acid, one of the hormonally active derivatives of vitamin A, occurs physiologically in plasma at a concentration below 10 nmol/l. The methods currently used for its quantification are based on HPLC, need about 1 ml of serum, are relatively laborious and thus not well suited for mass analysis. The affinity and specificity of retinoic acid receptors for all-trans-retinoic acid encouraged us to express both the entire human retinoic acid receptor beta (RAR-beta) and two versions of its retinoic acid-binding domain in Escherichia coli in the hope that these recombinant proteins might be used as binders in a ligand-binding assay for all-trans-retinoic acid. The recombinant receptors, the whole receptor [RAR-beta-(V7-Q448)], corresponding to domains A-F, and the ligand-binding domain [RAR-beta-(E149-Q448)], corresponding to domains D-F, were expressed in the vector pET 3d/BL21 (DE3) as inclusion bodies, solubilized with guanidinium chloride, renatured and purified by ion-exchange chromatography. RAR-beta-(P193-Q448), corresponding to domains E-F, was expressed in the vector pET 3d/BL21(DE3)pLysS, and purified by reversed-phase chromatography. Under non-denaturing conditions, the expressed whole receptor [RAR-beta-(V7-Q448)] and the D-F construct (RAR-beta-(E149-Q448)] behaved chromatographically as monomeric proteins whereas the E-F construct [RAR-beta-(P193-Q448)] had a strong tendency to aggregate. RAR-beta-(V7-Q448) and RAR-beta-(E149-Q448) had similar Kd values for all-trans-retinoic acid (1.4 and 0.6 nmol/l respectively) whereas RAR-beta-(P193-Q448) bound all-trans-retinoic acid less avidly (Kd 9.6 nmol/l). 9-cis-Retinoic acid bound to RAR-beta-(E149-Q448) and RAR-beta-(V7-Q448) as avidly as all-trans-retinoic acid. Competition experiments showed weak or no binding of 4-oxo-all-trans-retinoic acid, 4-oxo-13-cis-retinoic acid, 13-cis-retinoic acid, acitretin and retinol by RAR-beta-(E149-Q448).

scholarly journals Determinants of CoRNR-Dependent Repression Complex Assembly on Nuclear Hormone Receptors

2001 ◽  
Vol 21 (5) ◽  
pp. 1747-1758 ◽  
Author(s):  
Xiao Hu ◽  
Yun Li ◽  
Mitchell A. Lazar
Keyword(s):  
Retinoic Acid ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Retinoic Acid Receptor ◽  
Nuclear Hormone Receptor ◽  
Nuclear Hormone Receptors ◽  
Complex Assembly ◽  
Acid Receptor ◽  
Repression Complex ◽  
The Individual

ABSTRACT Ligand-dependent exchange of coactivators and corepressors is the fundamental regulator of nuclear hormone receptor (NHR) function. The interaction surfaces of coactivators and corepressors are similar but distinct enough to allow the ligand to function as a switch. Multiple NHRs share features that allow corepressor binding, and each of two distinct corepressors (N-CoR and SMRT) contains two similar CoRNR motifs that interact with NHRs. Here we report that the specificity of corepressor-NHR interaction is determined by the individual NHR interacting with specific CoRNR boxes within a preferred corepressor. First, receptors have distinct preferences for CoRNR1 versus CoRNR2. For example, the retinoic acid receptor binds CoRNR1, while RXR interacts almost exclusively with CoRNR2. Second, the NHR preference for N-CoR or SMRT is due to differences in CoRNR1 but not CoRNR2. Moreover, within a single corepressor, affinity for different NHRs is determined by distinct regions flanking CoRNR1. The highly specific determinants of NHR-corepressor interaction and preference suggest that repression is regulated by the permissibility of selected receptor-CoRNR-corepressor combinations. Interestingly, different NHR surfaces contribute to binding of CoRNR1 and CoRNR2, suggesting a model to explain corepressor binding to NHR heterodimers.

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