Notch signaling defines an evolutionarily conserved cell communication mech
anism, which enables neighboring cells to adopt different fates. Furthermor
e, Notch signaling may create boundaries that direct both the growth and pa
tterning of the developing organs. Here we report on the expression of Notc
h receptors during the development of rodent incisors. Before the aquisitio
n of their characteristic shape, incisors rotate antero-posteriorly and bec
ome asymmetric at their labial-lingual axis. Notch2 is expressed only in th
e anterior part of the developing incisors, well before their rotation, whi
le Notch2 expression was symmetrical in the developing molars. This is the
first demonstration of an asymmetric gene expression pattern during the rot
ation of the rodent incisors. (C) 2000 Elsevier Science Ireland Ltd. All ri
ghts reserved.