Thelin-11LIM homeobox gene specifies olfactory and chemosensory neuron fates inC. elegans

Abstract

Chemosensory neuron diversity in C. elegans arises from the action of transcription factors that specify different aspects of sensory neuron fate. In the AWB and AWA olfactory neurons, the LIM homeobox gene lim-4 and the nuclear hormone receptor gene odr-7 are required to confer AWB and AWA-specific characteristics respectively, and to repress an AWC olfactory neuron-like default fate. Here, we show that AWA neuron fate is also regulated by a member of the LIM homeobox gene family, lin-11. lin-11 regulates AWA olfactory neuron differentiation by initiating expression of odr-7, which then autoregulates to maintain expression. lin-11 also regulates the fate of the ASG chemosensory neurons, which are the lineal sisters of the AWA neurons. We show that lin-11 is expressed dynamically in the AWA and ASG neurons, and that misexpression of lin-11 is sufficient to promote an ASG, but not an AWA fate, in a subset of neuron types. Our results suggest that differential temporal regulation of lin-11, presumably together with its interaction with asymmetrically segregated factors, results in the generation of the distinct AWA and ASG sensory neuron types. We propose that a LIM code may be an important contributor to the generation of functional diversity in a subset of olfactory and chemosensory neurons in C. elegans.

Comprehensive single-cell transcriptional profiling of a multicellular organism

“…4G), which arise from the same parental cell in the last round of C. elegans embryonic cell divisions. Their differentiation has previously been used as a model for the study of the regulation of cell fate decisions (40). In our data, 136 genes were differentially expressed between these two cell types (fold difference > 3, false discovery rate < 5%; Fig.…”

Postmitotic diversification of olfactory neuron types is mediated by differential activities of the HMG‐box transcription factor SOX‐2

“…Several previous studies have suggested that AWC is also a default identity state for several other amphid sensory neuron classes, as this ground state is revealed upon removal of the terminal selector gene of the respective amphid sensory identity. Specifically, loss of AWA identity in odr-7 or lin-11 mutants, loss of ASG identity in unc-130; odr-7 double mutants, or loss of AFD identity in ttx-1 mutants has been proposed to reveal an AWC ground state (Sagasti et al, 1999;Sarafi-Reinach & Sengupta, 2000;Sarafi-Reinach et al, 2001;Satterlee et al, 2001;Lanjuin et al, 2003). However, these conclusions were mainly if not exclusively based on the ectopic expression of the GPCR str-2, an AWC ON marker.…”

Transcriptome Dynamics in the Developing Larynx, Trachea, and Esophagus

“…LIM-homeodomain regulatory genes are expressed as progenitor cells exit the cell cycle and generate different neuron cell types in a spatiotemporal pattern. They are involved in developing thermosensory, olfactory, chemosensory, and mechanosensory neurons (Cassata et al, 2000;Sarafi-Reinach et al, 2001;Srivastava et al, 2010).…”