A Cell-Specific and Selective Effect on Transactivation by the Androgen Receptor

Gordon, Debra A.; Chamberlain, Nancy L.; Flomerfelt, Francis A.; Miesfeld, Roger L.

doi:10.1006/excr.1995.1099

Cited by 13 publications

(14 citation statements)

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“…[32][33][34] Furthermore, the existence of an accessory coactivator that interacts specifically with the AF-1 region has been suggested. Recently, an RNA molecule, a steroid- In the fibroblasts from the patient with androgen-insensitivity syndrome who had a normal androgen receptor gene, the degree of transactivation by the transfected intact androgen receptor (Panel B) or the androgen receptor-glucocorticoid receptor chimera (Panel C) was low because of defects in a coactivator specific for the activation function 1 (AF-1) region in the N-terminal region of the androgen receptor.…”

Section: Discussionmentioning

confidence: 99%

Androgen-Insensitivity Syndrome as a Possible Coactivator Disease

et al. 2000

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NDROGEN-insensitivity syndromes in 46,XY fetuses result in various degrees of impairment in genital virilization. 1 These syndromes are caused by mutations in the androgen receptor gene that result in decreased binding of androgen to the receptor. [2][3][4][5][6][7][8][9] As a consequence, the transcriptional activity of the androgen-androgen-receptor complex is reduced, and therefore, genital virilization is reduced. The androgen receptor, like other steroid hormone receptors, has two major transactivation domains 10 -activation function 1 (AF-1) in the N-terminal region 11-13 and activation function 2 (AF-2) in the C-terminal ligand-binding domain 14 -that interact with the target genes directly as well as indirectly by means of intermediary coactivators. 15 We describe a patient in whom the complete androgen-insensitivity syndrome was diagnosed on the basis of phenotypic and endocrinologic findings, but who had no mutations in the androgen receptor gene. Detailed studies revealed that transmission of the activation signal from the AF-1 region of the androgen receptor was disrupted, suggesting that a coactivator interacting with the AF-1 region of the androgen receptor was lacking in this patient. CASE REPORTA 19-year-old woman reported primary amenorrhea. The patient had normal breast development and normal female external genitalia, but she had no pubic or axillary hair, and the vagina was short (6 cm in length) and ended in a blind pouch. Abdominal exploration revealed no uterus, but testes were present, which were resected. Histologic examination of the testes revealed small numbers of immature Sertoli cells and germ cells and a moderate num-A ber of Leydig cells. Preoperatively, the patient's serum testosterone concentration was 614 ng per deciliter (21.3 nmol per liter) and her serum 5 a -dihydrotestosterone concentration was 49 ng per deciliter (1.7 nmol per liter); both values were within the normal range for men. The karyotype was 46,XY. The patient was given a diagnosis of complete androgen-insensitivity syndrome. Her two older sisters were not affected. METHODS Analysis of the Androgen ReceptorThe study was approved by the local institutional review committee, and written or oral informed consent for a genital-skin biopsy was obtained from the patient, another patient with complete androgen-insensitivity syndrome, and five normal men. Primary culture of genital-skin fibroblasts, androgen-binding assays, and sequence analysis of the androgen receptor gene were performed as previously described. 4-9 Tissue concentrations of androgen receptor messenger RNA (mRNA) were determined by a quantitative reverse-transcriptase-polymerase-chain-reaction assay (RT-PCR) as described previously. 16,17 Plasmid Construction and Reporter AssayWe constructed a firefly-luciferase-reporter vector (pGL3-MMTV), which was under the control of the mouse-mammarytumor virus (MMTV) promoter, by inserting the mouse-mammary-tumor virus long terminal repeat promoter 18 into a pGL3 basic vector (Promega). The expression vectors for ...

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Section: Discussionmentioning

confidence: 99%

Androgen-Insensitivity Syndrome as a Possible Coactivator Disease

et al. 2000

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“…For example, GR-dependent activation of liver-specific tyrosine aminotransferase requires both Ets and HNF3 factors bound to elements adjacent to an HRE (56). The accessory factors by themselves cannot initiate efficient induction of their targets (10,11,57), suggesting that steroid receptors may act to organize the assembly of a transcriptionally active complex of enhancer-bound factors as well as recruited non-DNA-binding proteins. Thus, specificity for a particular receptor may vary with the arrangement of accessory factors within a complex.…”

Section: Direct Interaction Between Aml3/cbf␣1 and Steroid Receptors-mentioning

confidence: 99%

AML3/CBFα1 Is Required for Androgen-specific Activation of the Enhancer of the Mouse Sex-limited Protein (Slp) Gene

Yang¹,

Robins

1999

Journal of Biological Chemistry

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A complex 120-base pair enhancer, derived from the mouse sex-limited protein (Slp) gene, is activated solely by the androgen receptor (AR) in specific tissues, although it contains a hormone response element recognized by several steroid receptors. The generation of this transcriptional specificity has been ascribed to the interactions of the receptor with tissue-specific nonreceptor factors bound to accessory sites within the enhancer. Protein-DNA interaction assays revealed two factors binding the 5 part of the enhancer that differ widely in abundance between cells showing AR-specific activation of the Slp element compared with those that also permit activation by glucocorticoid receptor (GR). The factor designated B formed a complex centered on the sequence TGTGGT, a core motif recognized by members of the AML/CBF␣ transcription factor family. This complex was competed by a high affinity binding site specific for AML/CBF␣ and was specifically supershifted by an antibody to AML3/CBF␣1, placing factor B within the AML3/CBF␣1 subclass. Interestingly, this factor was shown to bind to a second site in the 3 part of the enhancer, positioned between the two critical AR binding sites. Transfection studies revealed that AML1-ETO, a dominant-negative AML/CBF␣ construct, abrogated AR induction of the enhancer, but not of simple hormone response elements. Furthermore, overexpression of AML3/CBF␣1 could rescue the AML1-ETO repression. Finally, glutathione S-transferase-AML/CBF␣ fusion proteins demonstrated direct interaction between AML/ CBF␣ and steroid receptors. Although this interaction was equivalent between AML1/CBF␣2 and AR or GR, AML3/CBF␣1 showed stronger interaction with AR than with GR. These data demonstrate that AML3/CBF␣1 is functionally required for hormonal induction of the Slp enhancer and that direct, preferential protein-protein interactions may contribute to AR-specific activation. These results demonstrate an intriguing role of AML3/ CBF␣1 in steroid-as well as tissue-specific activation of target genes.Steroid receptors mediate a wide variety of hormonal effects by their direct modulation of gene expression. Transcriptional activation stems primarily from receptor recognition of specific DNA hormone response elements (HREs) 1 (1-3). However, it remains a paradox how the signaling pathways of receptors are distinguished at the DNA level in vivo, since in vitro several receptors recognize the same consensus HRE (4 -8). DNA elements that vary from the consensus and provide preferential recognition by a single receptor exist but have not yet proven broadly applicable (6, 9). A more versatile mechanism to generate specificity invokes the participation of nonreceptor factors bound to DNA sequences neighboring HREs of hormonally responsive genes (5, 10, 11). Differential interactions between such factors and steroid receptors may organize an enhancerspecific activation complex that confers transcriptional specificity dependent on information intrinsic to both the gene and the receptor.To study transcription...

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“…A number of prostate cell lines display elevated AR-dependent transcriptional activation relative to nonprostatic cell lines; the AR N terminus appears responsible for this enhanced receptor activity (Gordon et al, 1995), suggesting the existence of cofactors that modulate transcriptional activation by the AR N-terminal activation domain in prostate epithelial cells. Together, the current data support the notion that the AR N terminus contains multiple surfaces capable of interaction with general transcription factors and possibly additional adapter proteins.…”

Section: Introductionmentioning

confidence: 99%

Identification and Characterization of ART-27, a Novel Coactivator for the Androgen Receptor N Terminus

Markus

Taneja

Logan

et al. 2002

MBoC

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The androgen receptor (AR) is a ligand-regulated transcription factor that stimulates cell growth and differentiation in androgen-responsive tissues. The AR N terminus contains two activation functions (AF-1a and AF-1b) that are necessary for maximal transcriptional enhancement by the receptor; however, the mechanisms and components regulating AR transcriptional activation are not fully understood. We sought to identify novel factors that interact with the AR N terminus from an androgen-stimulated human prostate cancer cell library using a yeast two-hybrid approach designed to identify proteins that interact with transcriptional activation domains. A 157-amino acid protein termed ART-27 was cloned and shown to interact predominantly with the AR(153-336), containing AF-1a and a part of AF-1b, localize to the nucleus and increase the transcriptional activity of AR when overexpressed in cultured mammalian cells. ART-27 also enhanced the transcriptional activation by AR(153-336) fused to the LexA DNA-binding domain but not other AR N-terminal subdomains, suggesting that ART-27 exerts its effect via an interaction with a defined region of the AR N terminus. ART-27 interacts with AR in nuclear extracts from LNCaP cells in a ligand-independent manner. Interestingly, velocity gradient sedimentation of HeLa nuclear extracts suggests that native ART-27 is part of a multiprotein complex. ART-27 is expressed in a variety of human tissues, including sites of androgen action such as prostate and skeletal muscle, and is conserved throughout evolution. Thus, ART-27 is a novel cofactor that interacts with the AR N terminus and plays a role in facilitating receptor-induced transcriptional activation.

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A Cell-Specific and Selective Effect on Transactivation by the Androgen Receptor

Cited by 13 publications

References 0 publications

Androgen-Insensitivity Syndrome as a Possible Coactivator Disease

Androgen-Insensitivity Syndrome as a Possible Coactivator Disease

AML3/CBFα1 Is Required for Androgen-specific Activation of the Enhancer of the Mouse Sex-limited Protein (Slp) Gene

Identification and Characterization of ART-27, a Novel Coactivator for the Androgen Receptor N Terminus

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