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. Author manuscript; available in PMC: 2019 Mar 11.
Published in final edited form as: Methods Mol Biol. 2018;1840:163–180. doi: 10.1007/978-1-4939-8691-0_13

Fig. 2.

Fig. 2

Nuclear migration through constricted spaces in larval P cells. (A) Cartoon of P cells throughout L1 larval development; lateral view, ventral is down, anterior to the left. Shortly after hatching, P-cell cytoplasm (dark blue) covers the ventral surface of the larva, and there are six P-cell nuclei (red) on each lateral side. P cells narrow in early L1 and migrate during mid L1 to form a row of 12 P cells in the ventral cord by late L1. Migration usually initiates with the anterior-most pair of P cells. During nuclear migration, P-cell nuclei stretch from lateral to ventral. (B) A cross section of an L1 larva just before P-cell nuclear migration. In order for the P-cell nucleus (red) to migrate from the lateral to the ventral compartments of the P-cell cytoplasm (dark blue), it must squeeze through a narrow constriction between body wall muscles (tan) and the cuticle. Fibrous organ-elles (yellow) form posts in this constricted space to attach muscles to the cuticle. (C) A mid-L1 larva expressing an RFP P-cell nuclear marker in an otherwise wild-type animal. Anterior is left, and ventral is down and on the outside of the curve. The anterior-most pair of P cells has completed migration to the ventral cord (arrow). The next P-cell nucleus is stretched between lateral and ventral compartments; the dark space within the nucleus is nucleoplasm within the constricted space under body wall muscles. P-cell nuclei more posterior have yet to enter the constricted space. Image kindly provided by Courtney Bone (BioMarin). (D–F) Adult animals expressing unc-47::gfp to mark GABA neurons. Tails (t) are left, and heads (h) are right. Lateral view; ventral is down. (D) An unc-84(null) animal expressing an unc-84(+) transgene (transgenic animals express a red marker in the head) with 18 GABA-positive neurons (arrowheads). (E) An unc-84(null) animal with only 13 GABA-positive neurons (arrowheads) between the head and tail. (F) A cartoon showing all the GFP-marked GABA neurons in wild type. Reproduced from [34] with permission from Cell Press. We only count the 19 D-type motor neurons in the ventral cord (light blue), 12 of which are derived from P cells. The DVB in the tail and neurons in the head is derived from other lineages