Type: Sensory neuron (polymodal sensory?; chemosensory?, mechanosensory?) In MoW:IL2 Male Wiring Project:IL2L,
IL2R,
IL2DL,
IL2DR,
IL2VL,
IL2VR In Wormbase:IL2L, IL2R, IL2DL, IL2DR, IL2VL, IL2VR Lineage:AB alapaappp, AB alaappppp
AB alapappap, AB alappppap
AB alppapppp, AB arapppppp Location: Head Description: Neurons of inner labial sensilla. They have ciliated endings without rootlets. IL2 dendrite ending protrudes through the hole in the socket cell to the outside, hence, it is suggested that IL2 neurons are chemosensory. Stains with DiI/Ca Acetate, DiO, Di4ANEPPS and RH421 ((Burket et al., 2006; Mille and Shakes, 1995).
Although the six IL2 neurons have a similar gross structure and express many of the same genes, the lateral IL2s display different neuronal connectivity and morphology than the quadrant (dorsal & ventral) ones (Wang et al., 2010; MoW).
IL2 neurons display neuroplasticity and stage-specific remodeling; dorsal and ventral IL2s undergo significant dendrite arborization and axon remodeling during dauer development while this remodeling is much less striking in lateral IL2s.
When dauer larva are returned to favorable
environmental conditions, these IL2 dendritic arbors retract, leaving behind remnant branches in postdauer L4 and adult animals (Schroeder et al., 2013) Neurotransmitter/Neuropeptide:
- Acetylcholine (N.B. Although earlier reports suggested IL2 might be glutamatergic, more recent studies showed it is not)
(Serrano-Saiz et al., 2013; Lee et al., 1999; O. Hobert, pers. comm.) (Zhang et al, 2014; Loer, 2010; Duerr et al, 2008) Innexin expression:
- INX-18; in IL2L/R only
- UNC-9 (Altun et al., 2009) Receptor expression:
- DES-2; alpha subunit of a nicotinic acetylcholine receptor
- NPR-1; neuropeptide Y receptor like protein (in IL2L/R) (Coates and de Bono, 2002; Treinin. et al., 2001) Function:
- Regulates nictation, a dispersal behavior seen in dauer larva. Intact IL2 cilia and cholinergic transmission in the IL2 neurons are required for this function (Lee et al., 2012). Targeted activation of IL2 neurons in non-dauers does not induce nictation, possibly since IL2 neurons undergo a significant structural change at the dauer stage which may be required for control of this behavior (Albert and Riddle, 1983)
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IL2 quadrant (IL2(Q):IL2VL/VR, IL2DL/DR) neurons remodel with complex dendritic arbors in dauer
Embryonic development of IL2 neurons
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IL2L (AB alapaappp) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2L; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
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IL2R (AB alaappppp) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2R; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
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IL2VL (AB alppapppp) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2VL; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
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IL2VR (AB arapppppp) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2VR; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
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IL2DL (AB alapappap) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2DL; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
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IL2DR (AB alappppap) development in the embryo. Dorsal view. Bottom is left side of the embryo. Spheres indicate individual nuclei. Black sphere: ancestors of IL2DR; dark grey spheres: apoptotic cells; other cells follow the WA color code (after they acquire specific cell or tissue identities). 0 min is fertilization. Click on the movie for higher resolution rendition (by A. Santella & Z. Bao).
IL2 Sensory Endings
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3D reconstruction of the anterior sensory endings (cilia and dendrites) from high resolution serial section transmission electron micrographs. Bar 1 μm. Color code for the sensory endings is shown on the right-colors do not follow the WA color code. To expand, double click on the video, to return to original size, click "esc" (Doroquez et al., 2014)
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3D reconstruction of all amphid neuron cilia and associated socket and sheath cell processes. Modeled from serial section transmission electron micrographs (ssTEMs). Bar 1 μm. Color code for the sensory endings is shown on the left-colors do not follow the WA color code. To expand, double click on the video, to return to original size, click "esc" (Doroquez et al., 2014)
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3D reconstruction of IL1, IL2, OLL, OLQ and CEP sensory endings and associated glia. Colors do not follow the WA color code (purple; transition zone (TZ), lavender; CEP, blue; OLL and OLQ, beige; IL1, green; IL2, light pink; ILsh, dark pink; ILso, dark orange; OLso, light orange; OLsh, dark green; CEPso, light green; CEPsh).To expand, double click on the video, to return to original size, click "esc" (Doroquez et al., 2014)
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