TRANSCRIPTIONAL REGULATION OF THE MOUSE ALPHA-A-CRYSTALLIN GENE - ACTIVATION-DEPENDENT ON A CYCLIC AMP-RESPONSIVE ELEMENT (DE1 CRE) AND A PAX-6-BINDING SITE/
A. Cvekl et al., TRANSCRIPTIONAL REGULATION OF THE MOUSE ALPHA-A-CRYSTALLIN GENE - ACTIVATION-DEPENDENT ON A CYCLIC AMP-RESPONSIVE ELEMENT (DE1 CRE) AND A PAX-6-BINDING SITE/, Molecular and cellular biology, 15(2), 1995, pp. 653-660
Two cis-acting promoter elements (-108 to -100 and -49 to -33) of the
mouse alpha A-crystallin gene, which is highly expressed in the ocular
lens, were studied. Here we show that DE1 (-108 to -100; 5'TGACGGTG3'
), which resembles the consensus cyclic AMP (cAMP)-responsive element
sequence (CRE; 5'TGACGT[AIC] [A/G]3'), behaves like a functional CRE s
ite. Transfection experiments and electrophoretic mobility shift assay
s (EMSAs) using site-specific mutations correlated a loss of function
with deviations from the CRE consensus sequence. Results of EMSAs in t
he presence of antisera against CREE, Delta CREB, and CREM were consis
tent with the binding of CREB-like proteins to the DE1 sequence. Stimu
lation of alpha A-crystallin promoter activity via 8-bromo-cAMP, forsk
olin, or human T-cell leukemia virus type I Tax(1) in transfections an
d reduction of activity of this site in cell-free transcription tests
by competition with the somatostatin CRE supported the idea that DEI i
s a functional CRE. Finally, Pax-6, a member of the paired-box family
of transcription factors, activated the mouse alpha A-crystallin promo
ter in cotransfected COP-8 fibroblasts and bound to the -59 to -29 pro
moter sequence in EMSAs. These data provide evidence for a synergistic
role of Pax-6 and CREB-like proteins for high expression of the mouse
alpha A-crystallin gene in the lens.