COLOR CODE FOR ced-3 TAIL

Oct. 12, 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.

Figures 4c,d, 6 and 7 of White et al (1991) come from this specimen, ced-3 TAIL, which covers the lumbar commissures, pre-anal ganglion and posterior ventral nerve cord. Among the interesting features within the print set are several “undead cells” from the P11 and P12 lineages. Some have survived to form motor neurons in the pre-anal ganglion and ventral cord, while others have survived to form a supernumerary epithelial cell (hypodermis) and a rectal epithelial cell. P12pa has become an epithelial cell (see Fig 6 in White et al), and is marked on the print set with a Black X in the prints from sections “-50” to “0”.

Four daughters of P11 and P12 (Blue 1,3,15,16) have adopted fates similar to those of VC or VB motor neurons, forming neuromuscular junctions along the ventral nerve cord. Unlike normal motor neurons, these cells have retained many large dense core vesicles along their processes (compare print 323 to Figure 4c and print 505 to Figure 4d from the White et al paper).

The posterior 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. Also, the touch dendrite of PVM is not immediately recognizable, lacking large microtubules or mantle. This complicates the task of assigning exact cell identities in many cases.

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 (most taken directly from John White’s notes)

Blue numbers

1 P12aap undead, VC13-like fate branches marked 1A, 1B, etc

3 P12aaap undead, VB13-like fate

15 P11aap undead, VC12-like fate branches marked 15A to 15H

16 P11aaap undead, VB12-like fate

Bluegreen numbers

12 PDB

Red numbers

1 PVCR

2 PVCL

3 LUAR

4 LUAL

Black lettering

X P12pa undead, supernumerary hypodermal cell

see prints 0 to -50