COLOR CODE FOR ced-3 Anterior VC

Oct. 18, 2012

DHH interpretation

This wild type adult hermaphrodite was prepared for study of cell fates of “undead cells” which failed to undergo programmed cell death in a ced-3 (n717) mutant background. This mutant allele, isolated in the Horvitz lab, was first described by Ellis and Horvitz in a Worm Breeder’s Gazette article in Jan 1982 and in their paper in 1986. The TEM study of the adult mutant was conducted at MRC, and aimed to follow the exact cell fates of many “undead cells” (JG White et al., 1991). This study encompassed four animals, one for the hermaphrodite nose, one for the RVG and anterior ventral cord, another for anterior ventral cord, and one for the posterior ventral cord and tail cells.

Figure 4b from the White et al paper comes from this specimen, ced-3 Anterior VC, which covers the anterior ventral nerve cord. Among the interesting features within the print set is the “undead cell” P2aap, which is marked as Blue 27. This cell has adopted a VC-like neuronal cell fate, with a long posterior axon traveling close to other VC axons, near the dorsal edge of the ventral cord fascicle, close to the muscle plate. This cell many synapses, including several gap junctions on its cell body and a series of NMJs to the muscle arms of the ventral bodywall muscles (typical of normal VC neurons). The NMJ shown in Figure 4b corresponds to print #348 in this series.

The anterior ventral cord is vaguely disorganized, such that the command interneurons are less distinctive in size, and many axons from the motor neurons are slightly out of position near the muscle plate. This complicates the task of assigning exact cell identities in many cases.

The print series has two consecutive portions covering about 680 serial images; first are prints #1A to 135A, followed by prints #1-546. Print 1A is the most anterior, print 546 the most posterior. Not every section was photographed, so the actual thin section series was even longer.

References

HM Ellis and HR Horvitz (1982) On Death and Dying in C. elegans. WBG Vol. 7, No 1, p 67.

HM Ellis and HR Horvitz (1986) Genetic control of programmed cell death in the nematode. Cell 44: 817-829.

JG White, E Southgate and N Thomson (1991) On the nature of undead cells in the nematode Caenorhabditis elegans. Phil Trans R Soc Lond B 331: 263-71.

Color codes (all taken directly from John White’s notes)

Blue numbers

27 “VC-like” P2aap undead cell

28 AS?

29 VD3

30 DB

31 DA

32 VA

33 VB

34 VC1

Green numbers

12 VC?

13 VC?

14 VD?

15 AVA

16

17 AVA

18 DD?

19 AVB