PMC

Time-lapse confocal images of L3 larval stage (anterior left, ventral down) PVD 3^O branches growing toward each other (0–27.5 min, arrow indicates gap between branches), achieving contact (30 min, arrowhead) and then retracting (32.5–35 min) to leave intervening space (arrow). This spacing is preserved in the adult PVD dendritic network. Scale bar is 5 um. See .

Lateral view of adult from left side (anterior to left, ventral to bottom). PVD::GFP (A) with FLP neuron marker, pmec-7::RFP, (B) and merged image (C) demonstrate that PVD dendritic branches (green) do not overlap with FLP (red) in the anterior (inset). Schematic showing that PVD and FLP envelop the animal with similar dendritic branching patterns (D). Scale bar is 15 um.

Time-lapse confocal images and schematic tracings of L4 larval stage (anterior left, ventral down) illustrating dynamic outgrowth of 4^O dendrites from established 3^O branches. Nascent 4^O branches (0 min) continue to grow throughout the L4 stage until they produce the mature menorah-like structures observed in the adult. Arrow denotes an example of a maturing 4^O branch. Asterisk (*, 0 min) indicates a nascent 4^O branch that ultimately retracts (60 min). Scale bar indicates 25 um. See .

(A). Confocal image of an adult worm (anterior to left, ventral to bottom) showing the PVD::GFP marker (arrows denotes other neurons in head and tail that express GFP). Insets show more highly magnified image (B) and schematic tracing (C) of region surrounding PVD soma. Note dendritic branches (1^O, 2^O, 3^O, and 4^O) and single ventrally projecting axon (arrowhead denotes location of ventral nerve cord). Scale bar is 15 um.

(A) Anti-FLAG immunostaining of L4 larval stage animal shows specific ser-2 prom3B::FLAG::PAB-1 expression in PVD (L and R) (box, inset) and OLL (L and R). Scale bar is 25 um. (B) Genes (with Wormbase annotation) encoding transcripts with elevated expression (1.5x) in the PVD/OLL microarray data set organized according to protein families or functional groups. Numbers denote genes in each group. (Table Inset) Enrichment of axon guidance proteins, including multiple UNC-6/Netrin pathway transcripts, enriched in the PVD/OLL microarray.

Confocal images (left) and schematic tracings (right) of PVD in L2 larval stage (A,B), panneural (C,D) and merged panels (E,F) demonstrate that both motor neuron commissures (arrowheads) and sub-lateral nerve cords (arrow) are established before the majority of PVD dendritic branches emerge. PVD 1^O branches arise in the L2 stage (B,D) followed by sequential orthogonal branching of 2^O and 3^O branches in L3 larval stage (G,M). A mature PVD neuron with 4^O branches is largely completed by late L4 larval stage (I,J). Scale bar is 15 um.

Confocal images and schematic tracings of PVD::GFP (green/black) and panneural::dsRed (red/gray) (anterior left, ventral down) show that sub-lateral nerve cords (arrow) and PVD axon (arrowhead) are not altered in mec-3 mutants (B) in comparison to WT (A). Images (C) and schematics (D) from time-lapse confocal microscopy of wt L2 larval stage demonstrate dynamic PVD 2^O branches (1–3) that initiate and retract in vicinity of established 2^O branches (*) over 30 min period. Images (E) and schematics (F) of mec-3 mutants do not show PVD 2^O branch initiation during 190 min of observation. Scale bar is 5 um. See for wt and for mec-3.

Confocal images (left) and schematics (right) of RNAi-treated animals expressing PVD::GFP marker (anterior left, ventral down). (A,B) Empty vector (EV)-treated negative control. Positive control, mec-3 RNAi (E-F), results in reduced 2^O and 3^O branches. lin-39 RNAi-treated animals (C-D) do not show PVD neurons (open circle indicates location of wt PVD cell body, arrow points to tail neuron that also expresses PVD::GFP marker). Mutants egl-46(gk692) shows fewer 2^O branches (G,H) and ahr-1(ju145) displays increased numbers of 2^O branches (I,J) (). Proposed temporal order of transcription factor function during PVD morphogenesis (M). ()

Time-lapse confocal images of L3 larva depict PVDL dendritic outgrowth (anterior left, ventral down). (Top panel) PVD 2^O branch makes a 90^o turn (arrow) to fasciculate with sub-lateral nerve cord where it becomes a tertiary branch (inset, 0 min). A 3^O branch with opposite polarity emerges from the point of turning (arrow) and grows toward the posterior (60 min). 4^O branches are established by a similar mechanism (240 min) in which 4^O branches at each end of the menorah-like structure (arrowheads) are generated by 90^O turns. Additional, interstitial 4^O branches emerge from the outer edge of the 3^O branch. Scale bar is 5 um. See for example.

Confocal images of PVD::GFP marker (A-D,P), panneural::dsRed (E-H,P) and merged reporters (I-L,O,P) show PVD dendritic branches, motor neuron commissures (arrow head) and sub-lateral nerve cords (arrow). PVD secondary branches lie in the same plane as motor neuron commissures as shown in rotated Z-stack from PVDR [(B,F,J)(rotated 55^O on the X-axis and 45^O on the y-axis)]. Rotated Z-stack of left side (ventral up) shows circumferential 4^O branches [(C,G,K (rotated 80^O on X-axis and 90^O on Y-axis)]. PVD 3^O branches fasciculate with dorsal and ventral sublateral nerve cords (D,H,L,O)(anterior left, ventral down). Schematic transverse section (M) shows PVD (L+R) (black) and fasciculation of some 2^O branches (left) but not others (right) with motor neuron commissures (red). Lateral view of PVDR (N,O) showing 3^O branches fasciculated with sub-lateral nerve chords (arrow). PVDR fasciculates with processes in the sub-lateral nerve cords (P, arrow) but does not contact the touch neuron, PVMR (P, arrowhead). Scale bars are 10um (A-C,E-G,I-K,O) or 15 um (D,H,L,P). See .