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SRY and architectural gene regulation: The kinetic stability of a bent protein-DNA complex can regulate its transcriptional potency
Ukiyama E.3; Jancso-Radek A.2; Li B.2; Milos L.2; Zhang W.; Phillips N.B.2; Morikawa N.3; King C.-Y.2; Chan G.2; Haqq C.M.3; Radek J.T.2; Poulat F.1; Donahoe P.K.3; Weiss M.A.2
2001
Source PublicationMolecular Endocrinology
ISSN08888809
Volume15Issue:3Pages:363-377
Abstract

Protein-directed DNA bending is proposed to regulate assembly of higher-order DNA-multiprotein complexes (enhanceosomes and repressosomes). Because transcriptional initiation is a nonequilibrium process, gene expression may be modulated by the lifetime of such complexes. The human testis-determining factor SRY contains a specific DNA-bending motif, the high-mobility group (HMG) box, and is thus proposed to function as an architectural factor. Here, we test the hypothesis that the kinetic stability of a bent HMG box-DNA complex can in itself modulate transcriptional potency. Our studies employ a cotransfection assay in a mammalian gonadal cell line as a model for SRY-dependent transcriptional activation. Whereas sex-reversal mutations impair SRY-dependent gene expression, an activating substitution is identified that enhances SRY's potency by 4-fold. The substitution (l13F in the HMG box; fortuitously occurring in chimpanzees) affects the motif's cantilever side chain, which inserts between base pairs to disrupt base pairing. An aromatic F13 cantilever prolongs the lifetime of the DNA complex to an extent similar to its enhanced function. By contrast, equilibrium properties (specific DNA affinity, specificity, and bending; thermodynamic stability and cellular expression) are essentially unchanged. This correlation between potency and lifetime suggests a mechanism of kinetic control. We propose that a locked DNA bend enables multiple additional rounds of transcriptional initiation per promoter. This model predicts the occurrence of a novel class of clinical variants, bent but unlocked HMG box-DNA complexes with native affinity and decreased lifetime. Aromatic DNA-intercalating agents exhibit analogous kinetic control of transcriptional elongation whereby chemotherapeutic potencies correlate with drug-DNA dissociation rates.

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Protein-directed DNA bending is proposed to regulate assembly of higher-order DNA-multiprotein complexes (enhanceosomes and repressosomes). Because transcriptional initiation is a nonequilibrium process, gene expression may be modulated by the lifetime of such complexes. The human testis-determining factor SRY contains a specific DNA-bending motif, the high-mobility group (HMG) box, and is thus proposed to function as an architectural factor. Here, we test the hypothesis that the kinetic stability of a bent HMG box-DNA complex can in itself modulate transcriptional potency. Our studies employ a cotransfection assay in a mammalian gonadal cell line as a model for SRY-dependent transcriptional activation. Whereas sex-reversal mutations impair SRY-dependent gene expression, an activating substitution is identified that enhances SRY's potency by 4-fold. The substitution (l13F in the HMG box; fortuitously occurring in chimpanzees) affects the motif's cantilever side chain, which inserts between base pairs to disrupt base pairing. An aromatic F13 cantilever prolongs the lifetime of the DNA complex to an extent similar to its enhanced function. By contrast, equilibrium properties (specific DNA affinity, specificity, and bending; thermodynamic stability and cellular expression) are essentially unchanged. This correlation between potency and lifetime suggests a mechanism of kinetic control. We propose that a locked DNA bend enables multiple additional rounds of transcriptional initiation per promoter. This model predicts the occurrence of a novel class of clinical variants, bent but unlocked HMG box-DNA complexes with native affinity and decreased lifetime. Aromatic DNA-intercalating agents exhibit analogous kinetic control of transcriptional elongation whereby chemotherapeutic potencies correlate with drug-DNA dissociation rates.

DOI10.1210/mend.15.3.0621
URLView the original
Indexed BySCI
Language英语
WOS Research AreaEndocrinology & Metabolism ; Endocrinology & Metabolism
WOS SubjectEndocrinology & Metabolism ; Endocrinology & Metabolism
WOS IDWOS:000167342800003
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Cited Times [WOS]:24   [WOS Record]     [Related Records in WOS]
Document TypeJournal article
CollectionInstitute of Chinese Medical Sciences
Corresponding AuthorWeiss M.A.
Affiliation1.IGH Institut de Génétique Humaine
2.Case Western Reserve University
3.Massachusetts General Hospital
Recommended Citation
GB/T 7714
Ukiyama E.,Jancso-Radek A.,Li B.,et al. SRY and architectural gene regulation: The kinetic stability of a bent protein-DNA complex can regulate its transcriptional potency[J]. Molecular Endocrinology,2001,15(3):363-377.
APA Ukiyama E..,Jancso-Radek A..,Li B..,Milos L..,Zhang W..,...&Weiss M.A..(2001).SRY and architectural gene regulation: The kinetic stability of a bent protein-DNA complex can regulate its transcriptional potency.Molecular Endocrinology,15(3),363-377.
MLA Ukiyama E.,et al."SRY and architectural gene regulation: The kinetic stability of a bent protein-DNA complex can regulate its transcriptional potency".Molecular Endocrinology 15.3(2001):363-377.
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