Abstract
The mechanisms by which the diverse functional identities of neurons are generated are poorly understood.
C. elegans responds to thermal and chemical stimuli using 12 types of sensory neurons. The
Otx/otd homolog
ttx-1 specifies the identities of the AFD thermosensory neurons. We show here that
ceh-36 and
ceh-37, the remaining two
Otx-like genes in the
C. elegans genome, specify the identities of AWC, ASE, and AWB chemosensory neurons, defining a role for this gene family in sensory neuron specification. All
C. elegans Otx genes and rat
Otx1 can substitute for
ceh-37 and
ceh-36, but only
ceh-37 functionally substitutes for
ttx-1. Functional substitution in the AWB neurons is mediated by activation of the same downstream target
lim-4 by different
Otx genes. Misexpression experiments indicate that although the specific identity adopted upon expression of an
Otx gene may be constrained by the cellular context, individual
Otx genes preferentially promote distinct neuronal identities.