Worm Breeder's Gazette 7(1): 68

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

The Death of mec-13

M. Chalfie

The touch cells die in animals carrying the dominant mutation e1611 (
Chalfie and Sulston, Devel.  Biol., 82: 358-370, 1981).  This mutation 
had been assigned as the only mutant allele of the gene mec-13 on the 
basis of the unique death phenotype and on somewhat shaky map data.  
However, recent attempts to make double mutants with e1504(mec-5) and 
e1497(mec-4) (by recombination with strains containing unc-7 suggested 
that e1611 is to the right of unc-7.  It now appears that e1611 is an 
allele of mec-4 X.  This assignment is suggested by the following 
1) Twelve e1611/lon-2(e678) mec-4(e1497) heterozygous gave 2711 Mec, 
868 Lon Mec, but no wild-type progeny.  Thus, e1611 is within 0.06 map 
units of mec-4(e1497).2) e1611 can be reverted to a recessive mec 
mutation.  A heterozygote strain, dpy-6(e14)e1611/szT1 was mutagenized 
with EMS and two of 3865 heterozygotes were wild-type (i.e.  non-Mec). 
One of these animals no longer produced Dpys and thus probably 
contains a deletion (e1878) that covers e1611.  The other, however, 
produced Dpy as wild-type progeny.  The new 
mutation (e1879) fails to complement e1497(mec-4).
Thus, e1611 is very close to and is likely to be an allele of mec-4.  
It is an intriguing problem how this missense mutation can lead to the 
selective death of the touch cells.