Regulation of alphaA-crystallin via Pax6, c-Maf, CREB and a broad domain of lens-specific chromatin.
Pax6 and c-Maf regulate multiple stages of mammalian lens development. Here, we identified novel distal control regions (DCRs) of the alphaA-crystallin gene, a marker of lens fiber cell differentiation induced by FGF-signaling. DCR1 stimulated reporter gene expression in primary lens explants treated with FGF2 linking FGF-signaling with alphaA-crystallin synthesis. A DCR1/alphaA-crystallin promoter (including DCR2) coupled with EGFP virtually recapitulated the expression pattern of alphaA-crystallin in lens epithelium and fibers. In contrast, the DCR3/alphaA/EGFP reporter was expressed only in 'late' lens fibers. Chromatin immunoprecipitations showed binding of Pax6 to DCR1 and the alphaA-crystallin promoter in lens chromatin and demonstrated that high levels of alphaA-crystallin expression correlate with increased binding of c-Maf and CREB to the promoter and of CREB to DCR3, a broad domain of histone H3K9-hyperacetylation extending from DCR1 to DCR3, and increased abundance of chromatin remodeling enzymes Brg1 and Snf2h at the alphaA-crystallin locus. Our data demonstrate a novel mechanism of Pax6, c-Maf and CREB function, through regulation of chromatin-remodeling enzymes, and suggest a multistage model for the activation of alphaA-crystallin during lens differentiation.
Yang
Ying
Y
Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Stopka
Tomás
T
Golestaneh
Nady
N
Wang
Yan
Y
Wu
Kongming
K
Li
Anping
A
Chauhan
Bharesh K
BK
Gao
Chun Y
CY
Cveklová
Kveta
K
Duncan
Melinda K
MK
Pestell
Richard G
RG
Chepelinsky
Ana B
AB
Skoultchi
Arthur I
AI
Cvekl
Ales
A