TY - JOUR
T1 - A naturally occurring mutation in the human androgen receptor of a subject with complete androgen insensitivity confers binding and transactivation by estradiol
AU - Bonagura, Thomas W.
AU - Deng, Min
AU - Brown, Terry R.
N1 - Funding Information:
Submitted by TWB in partial fulfillment of the requirements for the Doctor of Philosophy degree to Johns Hopkins University. TWB was supported by NICHD Training grant T32 HD07276.
Funding Information:
Supported by NIDDK grant R01 DK53048 to TRB.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/1/15
Y1 - 2007/1/15
N2 - The clinical phenotype of complete androgen insensitivity (CAIS) was associated with a mutation in the human androgen receptor (hAR) gene encoding the amino acid substitution, M745I, in the hAR protein. Transcriptional activation of hAR(M745I) by the synthetic androgen, methyltrienolone (R1881), was reduced compared to wild-type (wt) hAR. The transcriptional co-activator, androgen receptor associated protein 70 (ARA70), failed to enhance transactivation of hAR(M745I) at lower concentrations of R1881 (0.01-0.1 nM), whereas the p160 co-activators, SRC-1 and TIF2, stimulated activity. Transcriptional activity of hAR(M745I) was stimulated by 1 or 10 nM R1881 and activity was further enhanced by co-expression of ARA70 similar to that of the hAR(wt). Transcriptional activity of hAR(wt) was minimally stimulated by estradiol (E2) without or with co-expression of ARA70, whereas 10 or 100 nM E2 increased transactivation by hAR(M745I) of the androgen-responsive MMTV-luciferase reporter gene by 10-fold and activity was further enhanced by ARA70. Increasing concentrations of E2 competed more effectively for binding of R1881 to hAR(M745I) than to hAR(wt), indicative of the preferential binding of E2 to the mutant hAR. Partial tryptic digestion of hAR wt and M745I revealed that activation of the mutant protein was reduced in the presence of R1881. By contrast, tryptic digestion showed that the mutant hAR was activated by the binding of E2. In conclusion, the clinical phenotype of CAIS resulted from a hAR gene mutation encoding hAR(M745I) with reduced binding and transactivation by androgens, but the novel properties of enhanced affinity for and increased transactivation by estradiol.
AB - The clinical phenotype of complete androgen insensitivity (CAIS) was associated with a mutation in the human androgen receptor (hAR) gene encoding the amino acid substitution, M745I, in the hAR protein. Transcriptional activation of hAR(M745I) by the synthetic androgen, methyltrienolone (R1881), was reduced compared to wild-type (wt) hAR. The transcriptional co-activator, androgen receptor associated protein 70 (ARA70), failed to enhance transactivation of hAR(M745I) at lower concentrations of R1881 (0.01-0.1 nM), whereas the p160 co-activators, SRC-1 and TIF2, stimulated activity. Transcriptional activity of hAR(M745I) was stimulated by 1 or 10 nM R1881 and activity was further enhanced by co-expression of ARA70 similar to that of the hAR(wt). Transcriptional activity of hAR(wt) was minimally stimulated by estradiol (E2) without or with co-expression of ARA70, whereas 10 or 100 nM E2 increased transactivation by hAR(M745I) of the androgen-responsive MMTV-luciferase reporter gene by 10-fold and activity was further enhanced by ARA70. Increasing concentrations of E2 competed more effectively for binding of R1881 to hAR(M745I) than to hAR(wt), indicative of the preferential binding of E2 to the mutant hAR. Partial tryptic digestion of hAR wt and M745I revealed that activation of the mutant protein was reduced in the presence of R1881. By contrast, tryptic digestion showed that the mutant hAR was activated by the binding of E2. In conclusion, the clinical phenotype of CAIS resulted from a hAR gene mutation encoding hAR(M745I) with reduced binding and transactivation by androgens, but the novel properties of enhanced affinity for and increased transactivation by estradiol.
KW - ARA70
KW - Androgen
KW - Androgen receptor
KW - Estradiol
KW - Human androgen insensitivity syndrome
KW - Nuclear receptor co-activators
UR - http://www.scopus.com/inward/record.url?scp=37849189339&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=37849189339&partnerID=8YFLogxK
U2 - 10.1016/j.mce.2006.08.012
DO - 10.1016/j.mce.2006.08.012
M3 - Article
C2 - 17011702
AN - SCOPUS:37849189339
SN - 0303-7207
VL - 263
SP - 79
EP - 89
JO - Molecular and Cellular Endocrinology
JF - Molecular and Cellular Endocrinology
IS - 1-2
ER -