R. Meech et al., A binding site for homeodomain and Pax proteins is necessary for L1 cell adhesion molecule gene expression by Pax-6 and bone morphogenetic proteins, P NAS US, 96(5), 1999, pp. 2420-2425
Citations number
41
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
The cell adhesion molecule L1 regulates axonal guidance and fasciculation d
uring development. We previously identified the regulatory region of the L1
gene and showed that it was sufficient for establishing the neural pattern
of L1 expression in transgenic mice. In the present study, we characterize
a DNA element within this region called the HPD that contains binding moti
fs for both homeodomain and Pax proteins and responds to signals from bone
morphogenetic proteins (BMPs). An ATTA sequence within the core of the HPD
was required for binding to the homeodomain protein Barx2 while a separate
paired domain recognition motif was necessary for binding to Pax-6, In cell
ular transfection experiments, L1-luciferase reporter constructs containing
the HPD were activated an average of 4-fold by Pax-6 in N2A cells and 5-fo
ld by BMP-2 and BMP-4 in Ng108 cells. Both of these responses were eliminat
ed on deletion of the HPD from L1 constructs. In transgenic mice, deletion
of the HPD from an L1-lacZ reporter resulted in a loss of beta-galactosidas
e expression in the telencephalon and mesencephalon. Collectively, our expe
riments indicate that the HPD regulates L1 expression in neural tissues,ia
homeodomain and Pax proteins and is likely to be a target of BMP signaling
during development.