Activity of the C. elegans egg-laying behavior circuit is controlled by competing activation and feedback inhibition
- University of Miami, United States
- Yale University, United States
Figures
Figure 1
Cell-specific reporters of activity in the C.elegans egg-laying behavior circuit.
(A) Schematic of the circuit. HSN (green) and VC (blue) motor neurons synapse onto the vm2 muscle postsynaptic termini (center of schematic). The uv1 neuroendocrine cells (pink) extend processes …
Figure 2 with 1 supplement
HSN, VC, and vulval muscle activity is rhythmic and phased with animal locomotion.
(A) Active-state segments, such as the one shown here, were extracted from Ca2+ recordings, and analyzed for rhythmicity by power spectrum analysis. Underlying rhythm frequencies and peak …
Figure 2—figure supplement 1
Relative timing of HSN, VC, and vulval muscle Ca2+ transients during locomotion body bends.
The position of the vulva within a sinusoidal locomotor body bend was used to assign a body bend ‘phase’, in units of degrees, for each Ca2+ transient analyzed in Figure 1 as described in the …
Figure 3
Optogenetic activation of HSN neurons initiates the egg-laying active state, and optogenetic activation of VC neurons slows locomotion.
(A) Animals expressing Channelrhodopsin-2 (ChR2) in the HSNs and GCaMP5/mCherry in the VC neurons were grown in the presence (+ATR; top, blue) or absence (–ATR; bottom, black) of all-trans retinal. …
Figure 4 with 1 supplement
Active states require egg production but not the HSNs.
(A) Vulval muscle activity in wild-type animals either untreated or after sterilization with floxuridine (FUDR). Left panel shows 30 min recordings with the grey underlined regions expanded at …
Figure 4—figure supplement 1
Persistent phasing of rhythmic vulval muscle activity in animals lacking HSNs and after sterilization.
Phasing of vulval muscle Ca2+ transients during twitching (closed circles) and egg laying (open circles) in five untreated wild-type animals (A) and five animals sterilized with FUDR (B). Bar and …
Figure 5
The tyraminergic uv1 neuroendocrine cells are mechanically deformed and activated by egg laying.
(A) Fluorescence micrographs of uv1 showing GCaMP5, mCherry, and the GCaMP5/mCherry ratio before egg laying, during egg passage through the vulva, and after egg release. Times of movie frames in …
Figure 6
Tyramine inhibits egg laying, in part, through LGC-55 receptors on the HSNs.
(A) Exogenous tyramine inhibits egg-laying behavior and requires the LGC-55 receptor. Scatter plots and means showing the average number of eggs laid after 30 min by wild type (grey), tdc-1(n3419) …
Figure 7
Working model of how circuit connectivity, signaling, and activity contribute to the observed rhythms that accompany the active and inactive egg-laying behavior states.
VA and VB motor neuron synapses release acetylcholine (ACh) that rhythmically excites the body wall muscles (bwm) and vm1 vulval muscles during each locomotion body bend, every ~10 s. Eggs are …
Videos
Video 1
Ratio recording of HSN Ca2+ transients during the egg-laying active state.
High Ca2+ is indicated in red while low calcium is in blue. Large panel is an expanded view showing the freely-moving animal that has been contrast enhanced to make the worm and its laid eggs …
Video 2
Ratio recording of VC Ca2+ transients during the egg-laying active state.
High Ca2+ is indicated in red while low calcium is in blue. Contrast is enhanced to make the worm visible, although the laid eggs are not easily visible. Text labels indicate when vulval muscle (vm) …
Video 3
Ratio recording of vulval muscle Ca2+ transients during the egg-laying active state.
High Ca2+ is indicated in red while low calcium is in blue. Large panel is an expanded view showing the freely-moving animal that has been contrast enhanced to make the worm and its laid eggs …
Video 4
Activation of the HSNs using Channelrhodopsin-2 induces the egg-laying active state.
Animals were recorded for a total of 90 s with continuous blue light stimulation beginning at 30 s and ending at 60 s, during which five eggs are laid. Recording is sped up three-fold.
Video 5
Activation of the VCs using Channelrhodopsin-2 induces animal paralysis and shortening of body length.
Animals were recorded for a total of 90 s with continuous blue light stimulation beginning at 30 s and ending at 60 s. Recording is sped up 3-fold.
Video 6
Ratio recording of uv1 Ca2+ transients during the egg-laying active state.
High Ca2+ is indicated in red while low calcium is in blue. Large panel is an expanded view showing the freely-moving animal. Inset is cropped to a small area containing the uv1s, and stabilized to …
Tables
Table 1
Strains used in this study.
Strain | Feature | Genotype | Figures |
|---|---|---|---|
LX1832 | Strain for transgene production | lite-1(ce314) lin-15(n765ts) X | 1–6 |
LX1836 | HSN Channelrhodopsin | wzIs30 IV;lite-1(ce314) lin-15(n765ts) X | 3 |
LX1918 | vulval muscle GCaMP5, mCherry | lite-1(ce314) vsIs164 lin-15(n765ts) X | 1, 2 |
LX1932 | HSN Channelrhodopsin, vulval muscle GCaMP5, mCherry | wzIs30 IV; lite-1(ce314) vsIs164 lin-15(n765ts) X | 3 |
LX1938 | No HSNs, vulval muscle GCaMP5, mCherry | egl-1(n986dm) V; lite-1(ce314) vsIs164 lin-15(n765ts) X | 4 |
LX1986 | uv1 GCaMP5, mCherry | vsIs177; lite-1(ce314) lin-15(n765ts) X | 5 |
LX1960 | VC GCaMP5, mCherry | vsIs172; lite-1(ce314) lin-15(n765ts) X | 1, 2 |
LX1970 | HSN Channelrhodopsin, VC GCaMP5, mCherry | wzIs30 IV; vsIs172; lite-1(ce314) lin-15(n765ts) X | 3 |
LX2004 | HSN GCaMP5, mCherry | lite-1(ce314), vsIs183 lin-15(n765ts) X | 1, 2, 6 |
LX2038 | lgc-55 null mutant HSN GCaMP5, mCherry | lgc-55(tm2913) V lite-1(ce314) vsIs183 lin-15(n765ts) X | 6 |
MIA3 | VC Channelrhodopsin | keyIs3; lite-1(ce314) lin-15(n765ts) X | 3 |
MT13113 | tdc-1 null mutant; no tyramine biosynthesis | tdc-1(n3419) II | 6 |
N2 | Bristol strain | wild type | 6 |
OH313 | ser-2 null mutant | ser-2(pk1357) X | 6 |
VC125 | tyra-3 null mutant | tyra-3(ok325) X | 6 |
QW89 | lgc-55 null mutant | lgc-55(tm2913) V | 6 |
LX2096 | vulval muscle mCherry | vsIs191; lin-15(n765ts) X | |
LX2081 | pan-neuronal TagRFP | unc-119(ed3) I; otIs356 | |
LX2137 | vulval muscle mCherry, lgc-55::gfp | vsIs191; vsEx791 | 6 |
LX1330 | lgc-55 mutant expressing GFP in HSN from tph-1 promoter | lgc-55(tm2913) V; lin-15(n765ts) X vsEx557 | 6 |
LX1329 | lgc-55 mutant expressing LGC-55 in HSN from tph-1 promoter | lgc-55(thm2913) V; lin-15(n765ts) X vsEx558 | 6 |
