Sry-Directed Sex Reversal in Transgenic Mice Is Robust with Respect to Enhanced DNA Bending: Comparison of Human and Murine HMG Boxes
The testis-determining factor SRY contains an HMG box DNA-bending domain. Human and murine factors (hSRY and mSRY, respectively) exhibit marked sequence divergence and are reported to differ markedly in DNA bending properties. Surprisingly, the combined application of time-resolved fluorescence reso...
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Published in | Biochemistry (Easton) Vol. 43; no. 22; pp. 7066 - 7081 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
08.06.2004
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Subjects | |
Online Access | Get full text |
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Summary: | The testis-determining factor SRY contains an HMG box DNA-bending domain. Human and murine factors (hSRY and mSRY, respectively) exhibit marked sequence divergence and are reported to differ markedly in DNA bending properties. Surprisingly, the combined application of time-resolved fluorescence resonance energy transfer (tr-FRET) and permutation gel electrophoresis demonstrates that the hSRY−DNA complex is more sharply bent than the murine complex and not less bent as previously reported. tr-FRET-based analyses of the distribution of end-to-end distances in the bent DNA−protein complexes further suggest that a broader range of DNA bend angles is populated in the murine ensemble than in the human ensemble. The two domains and their respective DNA complexes nevertheless exhibit similar thermodynamic stabilities. 1H NMR spectra indicate analogous intercalation of distinct “cantilever” side chains (isoleucine or methionine) with subtle differences in induced DNA structure. Interchange of cantilevers does not affect DNA bending. That transgenic expression of either human or murine Sry in XX mice can confer a male somatic phenotype suggests that SRY-directed transcriptional regulation is robust to enhanced DNA bending and to changes in the precision of DNA bending. We propose that male-specific gene regulation requires DNA bending above a critical threshold set by architectural requirements of enhanceosome assembly. |
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Bibliography: | This work was supported in part by an Equipment Grant 553-99 from the Israel Science Foundation to E.H., Grant 98-362 from the United States/Israel Binational Foundation (E.H. and M.A.W.), and the National Institutes of Health Grant GM051558 (M.A.W.). V.I. and E.H. were supported in part by the Damadian Center for Magnetic Resonance Research at Bar Ilan University. ark:/67375/TPS-WS1Q41F9-S istex:0983317E6AC5B140D9CDCFEF621FE0ECB31DA7C8 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0006-2960 1520-4995 |
DOI: | 10.1021/bi049920a |