Precise temporal control of the eye regulatory gene Pax6 via enhancer-binding site affinity

Sheldon Rowan; Trevor Siggers; Salil A. Lachke; Yingzi Yue; Martha L. Bulyk; Richard L. Maas

doi:10.1101/gad.1890410

Precise temporal control of the eye regulatory gene Pax6 via enhancer-binding site affinity

¹Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
²Department of Pathology, Brigham and Women's Hospital and Harvard Medical, School, Boston, Massachusetts 02115, USA;
³Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology (HST), Harvard Medical, School, Boston, Massachusetts 02115, USA

↵4 These authors contributed equally to this work.

Abstract

How transcription factors interpret the cis-regulatory logic encoded within enhancers to mediate quantitative changes in spatiotemporally restricted expression patterns during animal development is not well understood. Pax6 is a dosage-sensitive gene essential for eye development. Here, we identify the Prep1 (pKnox1) transcription factor as a critical dose-dependent upstream regulator of Pax6 expression during lens formation. We show that Prep1 activates the Pax6 lens enhancer by binding to two phylogenetically conserved lower-affinity DNA-binding sites. Finally, we describe a mechanism whereby Pax6 levels are determined by transcriptional synergy of Prep1 bound to the two sites, while timing of enhancer activation is determined by binding site affinity.

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Footnotes

↵5 Corresponding authors.

E-MAIL mlbulyk{at}receptor.med.harvard.edu; FAX (617) 525-4705.
↵6 E-MAIL maas{at}genetics.med.harvard.edu; FAX (617) 525-4751.
Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.1890410.
Supplemental material is available at http://www.genesdev.org.
Received November 24, 2009.
Accepted March 17, 2010.