Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An androgen receptor (AR) gene mutation identified in the androgen-dependent human prostate cancer xenograft, CWR22, changed codon 874 in the ligand-binding domain (exon H) from CAT for histidine to TAT for tyrosine and abolished a restriction site for the endonuclease SfaNI. SfaNI digestion of AR exon H DNA from normal but not from prostate cancer tissue indicated H874Y is a somatic mutation that occurred before the initial tumor transplant. CWR22, an epithelial cell tumor, expresses a 9.6-kb AR mRNA similar in size to the AR mRNA in human benign prostatic hyperplasia. AR protein is present in cell nuclei by immunostaining as in other androgen-responsive tissues. Transcriptional activity of recombinant H874Y transiently expressed in CV1 cells in the presence of testosterone or dihydrotestosterone was similar to that of wild type AR. With dihydrotestosterone at a near physiological concentration (0.01 nM), H874Y and wild type AR induced 2-fold greater luciferase activity than did the LNCaP mutant AR T877A. The adrenal androgen, dehydroepiandrosterone (10 and 100 nM) with H874Y stimulated a 3- to 8-fold greater response than with wild type AR and at 100 nM the response was similar with the LNCaP mutant. H874Y, like the LNCaP cell mutant, was more responsive to estradiol and progesterone than was wild type AR. The antiandrogen hydroxyflutamide (10 nM) had greater agonist activity (4- to 7-fold) with both mutant ARs than with wild type AR. AR mutations that alter ligand specificity may influence tumor progression subsequent to androgen withdrawal by making the AR more responsive to adrenal androgens or antiandrogens.
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PMID:Dehydroepiandrosterone activates mutant androgen receptors expressed in the androgen-dependent human prostate cancer xenograft CWR22 and LNCaP cells. 909 97

Androgen insensitivity syndromes are due to defects in the androgen receptor gene. In this study, we analyzed the androgen receptor gene in four cases with complete androgen insensitivity syndrome. In patient 1, one substitutional mutation [arginine (codon CGC) to cysteine (codon TGC) at position 774] of exon F was identified. This position was located in the hormone binding domain and appeared to be one hot spot of mutations because the mutations at the same position in several unrelated cases were reported before. In patient 2, one substitutional mutation [tyrosine (codon TAT) to cysteine (codon TGT) at position 571] of exon B was identified. This position was located in the DNA binding domain. In patients 3 and 4 (siblings), one substitutional mutation [arginine (codon CGA) to glutamine (codon CAA) at position 752] of exon E was identified. Taken together, these abnormalities might be related to the pathogenesis of complete androgen insensitivity.
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PMID:Molecular analysis of the androgen receptor gene in 4 patients with complete androgen insensitivity. 954 75

The complete androgen insensitivity syndrome (AIS) is a sub-type of X-linked male pseudohermaphroditism resulting from total dysfunction of the androgen receptor. Affected patients are phenotypically female despite a 46,XY genotype; gonadal tissue displays a classic Sertoli cell-only pattern on microscopic examination. We describe the diagnosis and management of a 19(1/2)-year-old patient who presented for primary amenorrhea and absent cervix, identified incidentally during a routine Pap test. Serum total testosterone was elevated (725 ng/dl) and the karyotype was 46,XY. Molecular investigation for specific gene defect(s) causing disruption and functional incapacity of the androgen receptor was undertaken for the proband and her only sibling. From this we discovered a previously unknown hemizygous mutation (A-->T) in exon 4 of the androgen receptor gene, associated with replacement of asparagine (AAT) with tyrosine (TAT) in the resultant androgen receptor protein [N705Y]. Bidirectional, non-isotopic sequence analysis of exon 4 was next undertaken for the proband's sister who was found to be heterozygous for this mutation. Psychological and genetic counseling was provided to both individuals; the patient underwent an outpatient laparoscopic orchiectomy without complication. She continues to receive oral hormone replacement therapy following an oral contraceptive model. In this report, the clinical approach to AIS is outlined from a reproductive endocrinology perspective with special emphasis on psychological counseling and laboratory methods employed to confirm the diagnosis at the molecular level. We also outline other recently described mutations of the androgen receptor gene (Xq11-12) which have been associated with AIS.
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PMID:Characterization of a novel receptor mutation A-->T at exon 4 in complete androgen insensitivity syndrome and a carrier sibling via bidirectional polymorphism sequence analysis. 1174 94

It remains unclear why it has proven so difficult to identify androgen target genes in cultured Sertoli cells. Given the lack of useful endogenous reporter genes, we studied the androgen and glucocorticoid responsiveness of these cells by transfection with three different steroid-responsive reporter constructs. The constructs were driven by the tyrosine aminotransferase steroid-responsive region (TAT-GRE4x-Luc), the mouse mammary tumor virus promoter (MMTV-Luc) and the Pem homeobox gene proximal promoter respectively (Pem-Luc). These constructs can be activated either by both the glucocorticoid receptor (GR) and the androgen receptor (AR) (TAT-GRE4x-Luc and MMTV-Luc) or selectively by the AR (Pem-Luc). Despite high transfection efficiency (30-40%) none of the constructs could be activated by treatment of the Sertoli cells with testosterone, 5alpha-dihydrotestosterone or synthetic androgens. Even pretreatment with follicle-stimulating hormone to raise AR levels (from 31 up to 82fmol/mg protein) did not result in androgen responsiveness. In contrast, treatment with dexamethasone markedly stimulated TAT-GRE4x-Luc and MMTV-Luc activity. GR levels reached a value of 172fmol/mg protein in the cultured cells and both AR and GR displayed homogeneous distribution by immunocytochemical evaluation. Androgen responsiveness was restored and glucocorticoid responsiveness was increased by cotransfection with AR or GR expression constructs. Under cotransfection conditions, 1nM of testosterone (a concentration that is some 100 times lower than that estimated to be present in the testis) was sufficient to stimulate the TAT-GRE4x-Luc maximally. Our data indicate that cultured Sertoli cells respond better to glucocorticoids than to androgens and that one of the factors limiting androgen responsiveness is the availability of AR. Other factors limiting the transactivation capacity of the (endogenous) AR, however, cannot be excluded.
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PMID:Transfection with steroid-responsive reporter constructs shows glucocorticoid rather than androgen responsiveness in cultured Sertoli cells. 1638 47

Complete androgen insensitivity syndrome is an X-linked inherited disorder caused by mutations in the androgen receptor (AR) gene. Using polymerase chain reaction single-strand DNA conformational polymorphism and DNA sequencing, we identified a novel nonsense mutation in exon 1 of the AR gene in 2 Iranian brothers with complete androgen insensitivity syndrome. Despite a normal 46,XY karyotype, testes, and normal to elevated plasma levels of testosterone, they were born with female external genitalia and phenotype. This new mutation, a T-to-A transversion in exon 1, causes amino acid change of tyrosine (TAT) to ochre stop codon (TAA) at position 514 of the AR polypeptide. The Y514X mutation is located in a region that is normally important for the formation and function of the hormone receptor complex. We conclude that the novel Y514X mutation in the androgen receptor is the cause of complete androgen insensitivity syndrome in this family.
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PMID:Identification of a critical novel mutation in the exon 1 of androgen receptor gene in 2 brothers with complete androgen insensitivity syndrome. 1902 43

We previously demonstrated that ectopic expression of neurotrophic peptide (NP) derived from saposin C promotes androgen receptor (AR) expression and transactivation in human prostate cancer cells. This prompted us to investigate how NP or saposin C can function in cells. We constructed plasmids expressing saposin C or a chimeric peptide of a viral TAT transduction domain and saposin C (TAT-saposin C) with His-tag. Intracellular localization of saposin C and NP was predominantly shown in transfected cells, while TAT-saposin C was detected around membrane and in cytosol by immunofluorescence staining. Furthermore, induction of the AR expression and activation of the AR transcriptional function were observed in cells transfected with saposin C or TAT-saposin C, compared to control cells transfected with an empty plasmid. The effects of saposin C and TAT-saposin C on AR activity were examined in the presence of inhibitors of GPCR, MAPK1/2, and PI3K/Akt. Interestingly, we found that these inhibitors only affect AR activities in cells with TAT-saposin C expression but not with saposin C expression. Immunostaining images showed that co-localization of saposin C, Src, and the AR occurred in transfected cells. Physical interactions of saposin C/NP, Src, and the AR were then demonstrated by co-immunoprecipitation assays. Blockage of Src activity by specific inhibitor led to a decrease in the saposin C-mediated enhancement of AR transactivity, suggesting that intracellular expression of saposin C caused stimulation of AR expression and activity by associations with Src in LNCaP cells. This effect may not be mediated by GPCR.
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PMID:Associations of saposin C, Src, and androgen receptor upregulate the expression and function of androgen receptor in human prostate cancer cells. 2132 55

The visualization of the long noncoding RNA of prostate cancer gene 3 (lncRNA PCA3), a specific biomarker for androgen receptor-positive prostate cancer, in living cells not only directly reflects the gene expression and localization but also offers better insight into its roles in the pathological processes. Here, we loaded an entropy-driven RNA explorer (EDRE) on the TAT peptide-functionalized titanium carbide MXenes (Ti3C2-TAT) for the imaging of nuclear lncRNA PCA3 in live cells. The EDRE was condensed on the Ti3C2-TAT (Ti3C2-TAT@EDRE) by electrostatic interaction. Ti3C2-TAT@EDRE enables the entering of cells and release of TAT peptides and EDRE in the cytoplasm by the glutathione (GSH)-triggered cleavage of the disulfide bonds in Ti3C2-TAT. The released EDRE is delivered into the nucleus by the nucleus-targeted guidance of TAT peptides, and initiated by the target lncRNA PCA3, subsequently leading to the continuous accumulation of fluorescence signals. Consequently, fluorescence analysis of lncRNA PCA3 at low-picomolar concentrations in vitro as well as sensitive live cell imaging of lncRNA PCA3 in the nucleus of androgen receptor-positive LNCaP prostate cancer cells were achieved, providing a versatile strategy for the monitoring of nucleic acid biomarkers in the nucleus of living cells.
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PMID:Functional Titanium Carbide MXenes-Loaded Entropy-Driven RNA Explorer for Long Noncoding RNA PCA3 Imaging in Live Cells. 3158 15