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ABSTRACT: Prostate-specific antigen (PSA) is expressed at a high level in the luminal epithelial cells of the prostate and is absent or expressed at very low levels in other tissues. PSA expression can be regulated by androgens. Previously, two functional androgen-response elements were identified in the proximal promoter of the PSA gene. To detect additional, more distal control elements, DNasel-hypersensitive sites (DHSs) upstream of the PSA gene were mapped in chromatin from the prostate-derived cell line LNCaP grown in the presence and absence of the synthetic androgen R1881. In a region 4.8 to 3.8 kb upstream of the transcription start site of the PSA gene, a cluster of three DHSs was detected. The middle DNAseI-hypersensitive site (DHSII, at approximately -4.2 kb) showed strong androgen responsiveness in LNCaP cells and was absent in chromatin from HeLa cells. Further analysis of the region encompassing DHSII provided evidence for the presence of a complex, androgen-responsive and cell-specific enhancer. In transient transfected LNCaP cells, PSA promoter constructs containing this upstream enhancer region showed approximately 3000-fold higher activity in the presence than in the absence of R1881. The core region of the enhancer could be mapped within a 440-bp fragment. The enhancer showed synergistic cooperation with the proximal PSA promoter and was found to be composed of at least three separate regulatory regions. In the center, a functionally active, high-affinity androgen receptor binding site (GGAACATATTGTATC) could be identified. Mutation of this element almost completely abolished PSA promoter activity. Transfection experiments in prostate and nonprostate cell lines showed largely LNCaP cell specificity of the upstream enhancer region, although some activity was found in the T47D mammary tumor cell line.
Molecular Endocrinology 03/1997; 11(2):148-61. · 4.54 Impact Factor
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ABSTRACT: The ligand binding domain (LBD) and the amino-terminal, transactivation domain (TAD) of the androgen receptor (AR) were separately linked to the GAL4 DNA binding domain (DBD) and to the GAL4(TAD). Resulting constructs were tested in the yeast two-hybrid system for protein-protein interactions. In the presence of androgen [methyltrienolone (R1881) or dihydrotestosterone (DHT)] a transcriptionally active complex was formed, reflecting an association between the AR(LBD) and the AR(TAD). No interactions were found in the presence of low-affinity ligands like estradiol (E2), promegestone (R5020), or progesterone (Pg). Use of the Thr-868-Ala mutated AR(LBD) in the assay resulted not only in a clear AR TAD-LBD interaction in the presence of R1881 and DHT but also in the presence of E2, Pg, and R5020, corresponding to the alteration in ligand specificity induced by the mutation. Coexpression of the fusion protein Gal4(DBD)AR(LBD) and the separate AR(TAD) also gave rise to the formation of a transcriptionally active complex. No interactions were found between two AR LBDs at the low-expression level of the two components. However, LBD-LBD interaction was detectable by application of a high-expression vector for GAL4(TAD)AR(LBD), albeit at high ligand concentrations. To substantiate the observation of the AR LBD-TAD interaction, CHO cells were cotransfected with expression plasmids for a truncated AR, which lacks the TAD [AR(DBD)(LBD)], and for the separate AR(TAD). This resulted in stimulation of a MMTV-LUC reporter gene in the presence of R1881 but not in the absence of hormone. This finding indicates that, like in the yeast system, in mammalian cells, TAD-LBD interactions are of importance for AR activation. In the mammalian system, a maximal AR TAD-LBD interaction was obtained at approximately 10-fold higher ligand concentrations than required for full-length AR activation. In the presence of low-affinity ligands, the AR TAD-LBD interaction as measured by transcriptional activation was considerably weaker than the activity of the full-length AR. From the present results a concept of hormone-dependent AR activation is proposed, which requires a functional, direct or indirect intramolecular interaction between the TAD and the LBD.
Biochemistry 03/1997; 36(5):1052-64. · 3.42 Impact Factor
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ABSTRACT: Transglutaminases (TGases) are calcium-dependent enzymes catalysing the post-translational cross-linking of proteins. In the prostate at least two TGases are present, the ubiquitously expressed tissue-type TGase (TGC), and a prostate-restricted TGase (TGP). This paper deals with the molecular cloning and characterization of the cDNA encoding the human prostate TGase (hTGP). For this purpose we have screened a human prostate cDNA library with a probe from the active-site region of TGC. The largest isolated cDNA contained an open reading frame encoding a protein of 684 amino acids with a predicted molecular mass of 77 kDa as confirmed by in vitro transcription-translation and subsequent SDS/PAGE. The hTGP gene was tissue-specifically expressed in the prostate, yielding an mRNA of approx. 3.5 kb. Furthermore, a 3-fold androgen-induced upregulation of hTGP mRNA expression has been demonstrated in the recently developed human prostate cancer cell line, PC346C. Other well established human prostate cancer cell lines, LNCaP and PC-3, showed no detectable hTGP mRNA expression on a Northern bolt. The gene coding for prostate TGase was assigned to chromosome 3.
Biochemical Journal 06/1996; 315 ( Pt 3):901-8. · 4.90 Impact Factor
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ABSTRACT: Keratinocyte Growth Factor (KGF/FGF7) is a candidate andromedin in normal embryonic development of male accessory sex glands, such as the prostate and seminal vesicles. The expression of KGF mRNA and protein is androgen-responsive. To elucidate the regulation of expression of the KGF gene, we isolated the first two exons of the KGF gene and approximately 15 kb upstream sequences. The major transcription start site was mapped. It is preceded by a CAAT-box and a TATA-box. Transient transfections in LNCaP cells revealed that, upon treatment with the synthetic androgen R1881, KGF promoter activity is upregulated 6 to 11 fold, indicating androgen regulation of the KGF promoter in the region from position - 900 to -1200. The longest construct (BH-pLuc: -4700 to +901) has a much higher basal activity than the shorter constructs, indicating that in the region -4700 to -2700 additional activating sequences are present.
Biochemical and Biophysical Research Communications 04/1996; 220(3):858-63. · 2.48 Impact Factor
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ABSTRACT: To search for specific chromosome 8 aberrations in human prostate cancer, DNA was isolated from 44 human prostate tumor samples. Twenty six tumor samples were obtained from locally progressive tumors by transurethral resection, 12 were from radical prostatectomy specimens, and 6 were from lymph node metastases. Tumor DNAs were screened for allelic losses using 16 highly polymorphic microsatellite loci (14 covering the p arm, 2 on the q arm). In general, the detected deletions were large. In 59% of the tumor DNAs, allelic loss of 3 or more 8p loci was observed. Loss of 8p loci occurred in between 36 and 69% of the informative cases; for the two 8q markers, the percentages of loss were 11 and 25%, respectively, indicating preferential loss of (part of) 8p. In one tumor, two separate 8p deletions were found. The percentage of loss of heterozygosity was considerably higher in transurethral resection (65%) and lymph node metastases (83%) than in radical prostatectomy specimens (33%), suggesting that 8p deletion is a relatively late step in tumor progression. The maximal overlapping deleted region in all tumor DNAs is between the distal locus D8S133 and the proximal locus D8S87, indicating the localization of a candidate tumor suppressor gene within this region.
Cancer Research 01/1995; 54(23):6061-4. · 7.86 Impact Factor
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ABSTRACT: The interferon-alpha (IFN-alpha) regulated mouse Ifi54/Ifi56 gene family, which is composed of at least four members (Ifi54, Ifi56, Ifi56-ps1, and Ifi56-ps2), was isolated and characterized. In addition, the chromosomal localization of the four genes was determined. The Ifi54 and Ifi56 genes show an identical organization. Both are composed of a very small first exon and a second exon, which contains the complete open reading frame, except for the ATG start codon and the first two nucleotides of the second codon. In both genes, the two exons are separated by a small intron (5 and 2.5 kb, respectively). Expression of both genes is rapidly induced by IFN-alpha (within 2 h). The Ifi54 promoter region contains two sequences, which are closely related to the interferon stimulated response element (ISRE) consensus sequence (ISRE 1, GGTTTCAATTTCT, and ISRE 2, AGTGTTACTTTCT). The two elements are located directly adjacent to each other. A similar organization was recently established for the hamster Ifi54 promoter (Bluyssen et al., 1994). However, the mouse promoter is 70% less active than the hamster promoter. It turned out that ISRE 2 is hardly active, due to the G at position 4, which is a T in the hamster Ifi54 ISRE 2 and in the ISRE consensus sequence. The Ifi56 promoter region contains at a similar position two functional ISREs of identical strength (ISRE 1, AGTTTCAGTTTCT, and ISRE2, AGTTTCACTTTCC). In the Ifi56 promoter, the two ISRE motifs are separated by 6 bp. In addition to the Ifi56 gene, parts of two closely related genes (Ifi56-ps1 and Ifi56-ps2) were isolated. Both fragments contain an Ifi56-related open reading frame. However, we were unable to isolate the presumed first exon of Ifi56-ps1 and Ifi56-ps2, nor could we show expression of the genes. The Ifi54, Ifi56, Ifi56-ps1, and Ifi56-ps2 genes could all be assigned to mouse chromosome 19D1, suggesting a tight clustering.
Genomics 12/1994; 24(1):137-48. · 3.02 Impact Factor
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ABSTRACT: In this study, the minimal promoter requirements of the TATA-less human androgen receptor (hAR) gene promoter are described. The hAR promoter is characterized by a short GC-box (-59/-32) and a long homopurine stretch (-117/-60). Two major transcription initiation sites, AR transcription initiation site I (AR-TIS I, (+1/2/3)) and AR transcription initiation site II (AR-TIS II, (+12/13)) are located in a 13-base pair region (Faber, P. W., van Rooij, H. C. J., van der Korput, J. A. G. M., Baarends, W. M., Brinkmann, A. O., Grootegoed, J. A., and Trapman, J. (1991) J. Biol. Chem. 266, 10743-10749). Transient transfection of COS cells with hAR promoter deletion and mutant constructs, followed by RNA isolation and S1 nuclease protection analysis showed that the process of transcription initiation through AR-TIS I and AR-TIS II is regulated by different promoter sequences. The GC-box directed initiation from AR-TIS II but did not affect AR-TIS I utilization, which is dependent upon sequences between positions -5 and +57. Band shift analysis identified the transcription factor Sp1 as the protein interacting with the GC-box. A single Sp1 binding sequence was found to be present in the GC-box. Footprint analysis confirmed the interaction of Sp1 with this sequence. The differential initiation through AR-TIS I and AR-TIS II was substantiated by the introduction of point mutations in the Sp1 binding sequence: only mutations that specifically abolished Sp1 binding interfered with AR-TIS II utilization, but all mutations left AR-TIS I initiation intact.
Journal of Biological Chemistry 06/1993; 268(13):9296-301. · 4.77 Impact Factor
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ABSTRACT: In vivo effects of androgen withdrawal and substitution on human androgen receptor (hAR) expression were evaluated in the androgen-dependent human prostatic carcinoma tumor line PC-82. By application of several antibodies reactive with different epitopes of the hAR molecule, hAR protein expression was studied in tumor transplants by immunohistochemistry and immunoblotting. hAR messenger RNA (mRNA) levels were quantitated in PC-82 tumor tissue with a S1-nuclease protection assay. Most PC-82 tumor cells (> 97%) from testosterone-supplemented mice displayed nuclear hAR protein expression immunohistochemically. The almost complete reduction of nuclear hAR immunoreactivity within 5 days after androgen withdrawal (< 10%) was restored after androgen substitution within 1 day. The immunochemical data were confirmed by Western blot analysis. In contrast, no significant changes were observed in hAR mRNA content of PC-82 cells after 5 days of androgen withdrawal. Correlating hAR expression with proliferative activity of PC-82 tumor tissue during endocrine manipulation, a rapid, castration-induced decline of the percentage of bromodeoxyuridine-labeled cells accompanied the loss of hAR. Androgen substitution in castrated male mice restored the proliferative activity. However, this increase of proliferative activity lagged at least 24 h behind the normalization of the hAR protein level. In contrast to the steroid receptor down-regulation by homologous ligands observed in other experimental models, our data support the concept of hAR up-regulation by androgen. Since the hAR mRNA content of PC-82 tumor tissue was hardly affected by castration, expression of the hAR in PC-82 is thought to be modulated by translational and/or posttranslational mechanisms.
Endocrinology 01/1993; 131(6):3045-50. · 4.46 Impact Factor
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ABSTRACT: Screening a mouse genomic DNA library with human androgen-receptor (hAR) cDNA probes resulted in the isolation and characterization of eight genomic fragments that contain the eight exons of the mouse androgen-receptor (mAR) gene. On the basis of similarity to the hAR gene, the nucleotide sequences of the protein-coding parts of the exons as well as the sequences of the intron/exon boundaries were determined. An open reading frame (ORF) of 2697 nucleotides, which can encode an 899-amino-acid protein, could be predicted. The structure of the mAR ORF was confirmed by sequence analysis of mAR cDNA fragments, which were obtained by PCR amplification of mouse testis cDNA, using mAR specific primers. A eukaryotic mAR expression vector was constructed and mAR was transiently expressed in COS-1 cells. The expressed protein was shown by Western blotting to be identical in size with the native mAR. Co-transfection of HeLa cells with the mAR expression plasmid and an androgen-responsive chloramphenicol acetyltransferase (CAT) reporter-gene construct showed mAR to be able to trans-activate the androgen-responsive promoter in a ligand-dependent manner. Transcription-initiation sites of the mAR gene were identified by S1-nuclease protection experiments, and the functional activity of the promoter region was determined by transient expression of mAR promoter-CAT-reporter-gene constructs in HeLa cells. Structural analysis revealed the promoter of the mAR gene to be devoid of TATA/CCAAT elements. In addition, the promoter region is not remarkably (G + C)-rich. Potential promoter elements consist of a consensus Sp1 binding sequence and a homopurine stretch. The polyadenylation sites of mAR mRNA were identified by sequence similarity to the corresponding sites in the hAR mRNA.
Biochemical Journal 09/1991; 278 ( Pt 1):269-78. · 4.90 Impact Factor
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ABSTRACT: A full length human androgen receptor (hAR) cDNA was constructed from cDNA and genomic clones. Structurally the 10.6-kilobase (kb) hAR cDNA consists of a long 5'-untranslated region (5'-UTR, 1.1 kb), a previously described open reading frame (ORF, 2.7 kb) (Trapman, J., Klaassen, P., Kuiper, G. G. J. M., van der Korput, J. A. G. M., Faber, P. W., van Rooij, H. C. J., Geurts van Kessel, A., Voorhorst, M. M., Mulder, E., and Brinkmann, A. O. (1988) Biochem. Biophys. Res. Commun. 153, 241-248; Faber, P. W., Kuiper, G. G. J. M., van Rooij, H. C. J., van der Korput, J. A. G. M., Brinkmann, A. O., and Trapman, J. (1989) Mol. Cell. Endocrinol. 61, 257-262), and a very long 3'-untranslated region (3'-UTR, 6.8 kb). The complete 5'- and 3'-UTRs were found to be encoded by the previously reported first and eight protein coding exons of the hAR gene, respectively (Kuiper, G. G. J. M., Faber, P. W., van Rooij, H. C. J., van der Korput, J. A. G. M., Ris-Stalpers, C., Klaassen, P., Trapman, J., and Brinkmann, A. O. (1989) J. Mol. Endocrinol. 2, R1-R4). Two major sites of transcription initiation were identified in a 13-base pair region. DNA fragments spanning these transcription initiation sites conferred promoter activity upon a promoterless chloramphenicol acetyltransferase reporter gene construct. Two equally effective, functional polyadenylation signals (ATTAAA and CATAAA) at a mutual distance of 221 base pairs were detected. The ATTAAA hexamer sequence gave rise to multiple sites of poly(A) addition, whereas only one position was used following the CATAAA hexamer. In LNCaP prostatic carcinoma cells an alternatively spliced hAR mRNA species was identified which lacks 3 kb of the 3'-UTR.
Journal of Biological Chemistry 07/1991; 266(17):10743-9. · 4.77 Impact Factor
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ABSTRACT: The growth of the majority of prostate tumors is androgen-dependent, for which the presence of a functional androgen receptor is a prerequisite. Tumor growth can be inhibited by blockade of androgen receptor action. However, this inhibition is transient. To study the role of the androgen receptor in androgen-dependent and androgen-independent prostate tumor cell growth, androgen receptor mRNA expression was monitored in six different human prostate tumor cell lines and tumors, which were grown either in vitro or by transplantation on (male) nude mice. Androgen receptor mRNA was clearly detectable in three androgen-dependent (sensitive) tumors and absent or low in three androgen-independent tumors. Growth of the LNCaP prostate tumor cell line can be stimulated both by androgens and by fetal calf serum. In the former situation androgen receptor mRNA expression is downregulated, whereas in the latter no effect on androgen receptor mRNA levels can be demonstrated. Sequence analysis showed that the androgen receptor gene from LNCaP cells contains a point mutation in the region encoding the steroid-binding domain, which confers an ACT codon encoding a threonine residue to GCT, encoding alanine.
The Journal of Steroid Biochemistry and Molecular Biology 01/1991; 37(6):837-42. · 3.05 Impact Factor
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ABSTRACT: Androgen insensitivity is a disorder in which the correct androgen response in an androgen target cell is impaired. The clinical symptoms of this X chromosome-linked syndrome are presumed to be caused by mutations in the androgen receptor gene. We report a G----T mutation in the splice donor site of intron 4 of the androgen receptor gene of a 46,XY subject lacking detectable androgen binding to the receptor and with the complete form of androgen insensitivity. This point mutation completely abolishes normal RNA splicing at the exon 4/intron 4 boundary and results in the activation of a cryptic splice donor site in exon 4, which leads to the deletion of 123 nucleotides from the mRNA. Translation of the mutant mRNA results in an androgen receptor protein approximately 5 kDa smaller than the wild type. This mutated androgen receptor protein was unable to bind androgens and unable to activate transcription of an androgen-regulated reporter gene construct. This mutation in the human androgen receptor gene demonstrates the importance of an intact steroid-binding domain for proper androgen receptor functioning in vivo.
Proceedings of the National Academy of Sciences 11/1990; 87(20):7866-70. · 9.68 Impact Factor
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ABSTRACT: The complete coding region of the human androgen receptor gene has been isolated from a genomic library. The information for the androgen receptor was found to be divided over eight exons and the total length of the gene exceeded 90 kb. The sequence encoding the N-terminal region is present in one large exon. The two putative DNA-binding fingers are encoded separately by two small exons. The information for the hormone-binding domain is split over five exons. Positions of introns are identical to those reported for the chicken progesterone receptor and the human oestrogen receptor genes. Southern blot analysis of genomic DNA with various specific probes reveal that the human androgen receptor is encoded by a single-copy gene.
Journal of Molecular Endocrinology 06/1989; 2(3):R1-4. · 3.48 Impact Factor
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ABSTRACT: Using specific cDNA hybridization probes, the first coding exon of the human androgen receptor gene was isolated from a genomic library. The exon contained an open reading frame of 1586 bp, encoding an androgen receptor amino-terminal region of 529 amino acids. The deduced amino acid sequence was characterized by the presence of several poly-amino acid stretches of which the long poly-glycine stretch (16 residues) and the poly-glutamine stretch (20 residues) were most prominent. Androgen receptor cDNAs from different sources contained information for poly-glycine stretches of variable size (23 and 27 residues, respectively). The androgen receptor amino-terminal domain was found to be hydrophilic and have a net negative charge. Combined with the previously described, partially overlapping cDNA clone 7A2M27 (Trapman et al. (1988) Biochem. Biophys. Res. Commun. 153, 241-248), the complete human androgen receptor was deduced to have a size of 910 amino acids.
Molecular and Cellular Endocrinology 03/1989; 61(2):257-62. · 4.19 Impact Factor
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ABSTRACT: The domain structure and the genomic organization of the human androgen receptor (hAR) has been studied after molecular cloning and characterization of cDNA and genomic DNA encoding the hAR. The cDNA sequence reveals an open reading frame of 2751 nucleotides encoding a protein of 917 amino acids with a calculated molecular mass of 98,845 D. The N-terminal region of the hAR is characterized by a high content of acidic amino acid residues and by several homopolymeric amino acid stretches. The DNA-binding domain showed a high homology with the DNA-binding domain of the human glucocorticoid receptor (hGR) and the human progesterone receptor (hPR). The predominantly hydrophobic steroid binding domain of the hAR is 50-55% homologous with the ligand binding domains of the hGR and hPR. Transient expression of recombinant AR cDNA in COS-cells resulted in the production of a 110 kDa protein with the expected binding specificity of androgen receptors. Co-transfection with a reporter-gene construct [CAT(chloramphenicol acetyl transferase) under direction of the androgen regulated MMTV-promoter] showed that the protein is functionally active with respect to transcription regulation. In the LNCaP prostate carcinoma cell line two major (11 and 8 kb) and one minor (4.7 kb) mRNA species can be found which can be down-regulated by androgens. The hAR protein coding region was shown to be divided over eight exons with an organization similar to that of the progesterone and oestrogen receptor. The sequence encoding the N-terminal domain was found in one large exon. The two DNA-binding fingers were encoded by two small exons; the information for the androgen-binding domain was found to be distributed over five exons. Southern blot analysis of genomic DNA revealed that the hAR is encoded by one single gene, which is situated on the X-chromosome.
Journal of Steroid Biochemistry 02/1989; 34(1-6):307-10.
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ABSTRACT: The androgen receptor in several species (human, rat, calf) is a monomeric protein with a molecular mass of 100-110 kDa. The steroid binding domain is confined to a region of 30 kDa, while the DNA-binding domain has the size of approx. 10 kDa. A 40 kDa fragment containing both the DNA and steroid binding domain displayed a higher DNA binding activity than did the intact 100 kDa molecule. cDNA encoding the major part of the human androgen receptor was isolated. The cDNA contains an open reading frame of 2,277 bp but still lacks part of the 5'-coding sequence. Homology with the progesterone and glucocorticoid receptor was about 80% in the DNA binding domain and 50% in the steroid binding domain. The present data provide evidence that the androgen receptor belongs to the superfamily of ligand responsive transcriptional regulators and consists of three distinct domains each with a specialized function.
Urological Research 02/1989; 17(2):87-93. · 1.23 Impact Factor
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ABSTRACT: A cDNA clone has been isolated from a library prepared of mRNA of human breast cancer T47D cells with an oligonucleotide probe homologous to part of the region encoding the DNA-binding domain of steroid receptors. The clone has a size of 1505 bp and sequence analysis revealed an open reading frame of 1356 bp. The deduced amino acid sequence displays two highly conserved regions identified as the putative DNA-binding and hormone binding domains respectively of steroid receptors. Expression of this cDNA clone in COS cells produces a nuclear protein with all the binding characteristics of the human androgen receptor (hAR). The gene encoding the cDNA is assigned to the human X-chromosome. High levels of three hybridizing mRNA species of 11, 8.5 and 4.7 kb respectively are found in the human prostate cancer cell line (LNCaP), which contains elevated levels of hAR. The present data provide evidence that we have isolated a cDNA that encodes a major part of the human androgen receptor.
Biochemical and Biophysical Research Communications 06/1988; 153(1):241-8. · 2.48 Impact Factor
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A.O. Brinkmann, P.W. Faber,
H.C.J. van Rooij,
G.G.J.M. Kuiper,
C. Ris,
P. Klaassen,
J.A.G.M. van der Korput,
M.M. Voorhorst,
J.H. van Laar,
E. Mulder,
J. Trapman
[show abstract]
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ABSTRACT: The domain structure and the genomic organization of the human androgen receptor (hAR) has been studied after molecular cloning and characterization of cDNA and genomic DNA encoding the hAR. The cDNA sequence reveals an open reading frame of 2751 nucleotides encoding a protein of 917 amino acids with a calculated molecular mass of 98,845 D. The N -terminal region of the hAR is characterized by a high content of acidic amino acid residues and by several homopolymeric amino acid stretches. The DNA-binding domain showed a high homology with the DNA-binding domain of the human glucocorticoid receptor (hGR) and the human progesterone receptor (hPR). The predominantly hydrophobic steroid binding domain of the hAR is 50–55% homologous with the ligand binding domains of the hGR and hPR. Transient expression of recombinant AR cDNA in COS-cells resulted in the production of a 110 kDa protein with the expected binding specificity of androgen receptors. Co-transfection with a reporter-gene construct [CAT(chloramphenicol acetyl transferase) under direction of the androgen regulated MMTV-promoter] showed that the protein is functionally active with respect to transcription regulation. In the LNCaP prostate carcinoma cell line two major (11 and 8 kb) and one minor (4.7 kb) mRNA species can be found which can be down-regulated by androgens. The hAR protein coding region was shown to be divided over eight exons with an organization similar to that of the progesterone and oestrogen receptor. The sequence encoding the N-terminal domain was found in one large exon. The two DNA-binding fingers were encoded by two small exons; the information for the androgen-binding domain was found to be distributed over five exons. Southern blot analysis of genomic DNA revealed that the hAR is encoded by one single gene, which is situated on the X-chromosome.
Journal of Steroid Biochemistry.
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[show abstract]
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ABSTRACT: Using specific cDNA hybridization probes, the first coding exon of the human androgen receptor gene was isolated from a genomic library. The exon contained an open reading frame of 1586 bp, encoding an androgen receptor amino-terminal region of 529 amino acids. The deduced amino acid sequence was characterized by the presence of several poly-amino acid stretches of which the long poly-glycine stretch (16 residues) and the poly-glutamine stretch (20 residues) were most prominent. Androgen receptor cDNAs from different sources contained information for poly-glycine stretches of variable size (23 and 27 residues, respectively). The androgen receptor amino-terminal domain was found to be hydrophilic and have a net negative charge. Combined with the previously described, partially overlapping cDNA clone 7A2M27 (Trapman et al. (1988) Biochem. Biophys. Res. Commun. 153, 241–248), the complete human androgen receptor was deduced to have a size of 910 amino acids.
Molecular and Cellular Endocrinology.
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ABSTRACT: The growth of the majority of prostate tumors is androgen-dependent, for which the presence of a functional androgen receptor is a prerequisite. Tumor growth can be inhibited by blockade of androgen receptor action. However, this inhibition is transient. To study the role of the androgen receptor in androgen-dependent and androgen-independent prostate tumor cell growth, androgen receptor mRNA expression was monitored in six different human prostate tumor cell lines and tumors, which were grown either in vitro or by transplantation on (male) nude mice. Androgen receptor mRNA was clearly detectable in three androgen-dependent (sensitive) tumors and absent or low in three androgen-independent tumors. Growth of the LNCaP prostate tumor cell line can be stimulated both by androgens and by fetal calf serum. In the former situation androgen receptor mRNA expression is downregulated, whereas in the latter no effect on androgen receptor mRNA levels can be demonstrated. Sequence analysis showed that the androgen receptor gene from LNCaP cells contains a point mutation in the region encoding the steroid-binding domain, which confers an ACT coVon encoding a threonine residue to GCT, encoding alanine.
The Journal of Steroid Biochemistry and Molecular Biology.
