A G577R mutation in the human AR P box results in selective decreases in DNA binding and in partial androgen insensitivity syndrome

Citation
D. Nguyen et al., A G577R mutation in the human AR P box results in selective decreases in DNA binding and in partial androgen insensitivity syndrome, MOL ENDOCR, 15(10), 2001, pp. 1790-1802
Citations number
59
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
MOLECULAR ENDOCRINOLOGY
ISSN journal
0888-8809 → ACNP
Volume
15
Issue
10
Year of publication
2001
Pages
1790 - 1802
Database
ISI
SICI code
0888-8809(200110)15:10<1790:AGMITH>2.0.ZU;2-X
Abstract
We have characterized a novel mutation of the human AR, G577R, associated w ith partial androgen insensitivity syndrome. G577 is the first amino acid o f the P box, a region crucial for the selectivity of receptor/DNA interacti on. Although the equivalent amino acid in the GR (also Gly) is not involved in DNA interaction, the residue at the same position in the ER (Glu) inter acts with the two central base pairs in the PuGGTCA motif. Using a panel of 16 palindromic probes that differ in these base pairs (PuGNNCA) in gel shi ft experiments with either the AR DNA-binding domain or the full length rec eptor, we observed that the G577R mutation does not induce binding to probe s that are not recognized by the wild-type AR. However, binding to the four PuGNACA elements recognized by the wild-type AR was affected to different degrees, resulting in an altered selectivity of DNA response element recogn ition. In particular, ARG577R did not interact with PuGGACA palindromes. Mo deling of the complex between mutant AR and PuGNACA motifs indicates that t he destabilizing effect of the mutation is attributable to a steric clash b etween the C beta of Arg at position I of the P box and the methyl group of the second thymine residue in the TGTTCP gamma arm of the palindrome. In a ddition, the Arg side chain can interact with G or T at the next position ( PuGCACA and PuGAACA elements, respectively). The presence of C is not favor able, however, because of incompatible charges, abrogating binding to the P uGGACA element. Transactivation of several natural or synthetic promoters c ontaining PuGGACA motifs was drastically reduced by the G577R mutation. The se data suggest that androgen target genes may be differentially affected b y the G577R mutation, the first natural mutation characterized that alters the selectivity of the AR/DNA interaction. This type of mutation may thus c ontribute to the diversity of phenotypes associated with partial androgen i nsensitivity syndrome.