Worm Breeder's Gazette 8(1): 8

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.

Muscle Defective Revertants of unc-105(n490)

A. Bejsovec, P. Anderson

We have isolated a variety of muscle defective mutants by reverting 
the paralyzed mutant unc-105(n490).  n490 is severely paralyzed, 
apparently due to hyper-contraction of body-wall muscle cells.  
Revertants having improved motility are easily visualized among their 
paralyzed siblings.  Wild-type revertants have been described by Joan 
Park (see Newsletter 7:49) as null alleles of unc-105.  We find that 
partial revertants of n490 are often muscle defective.  Being muscle 
defective, such mutants are unable to generate the force required for 
the n490 mutant phenotype.  Thus, they are isolated as suppressors of 
hyper-contraction.  Although these revertant strains have an 
uncoordinated phenotype, they are usually more motile than n490, and 
this serves as the basis for their selection.  We used this reversion 
to isolate spontaneous unc-54 and unc-22 mutations (see 1983 Meeting 
Abstracts), and have now begun to analyze other classes of n490 
revertants.  We hope that among these revertants will be novel muscle 
defective mutants.
We mutagenized cultures of n490 and picked partial revertants among 
the F2 progeny.  As expected, many Twitcher revertants (presumably unc-
22) were observed; we have not analyzed this class.  The remaining 
partial revertants were screened for abnormal muscle using polarized 
light microscopy.  We are in the process of analyzing 117 partial 
revertants of n4900 74 of these revertants are muscle defective.  Thus 
far, we have identified twenty additional alleles of unc-54 and one 
allele each of unc-52, utations 
complement alleles of all the known genes having a similar muscle 
defective mutant phenotype.  These mutations may define new muscle 
genes.  Interestingly, another 21 of the muscle defective revertants 
appear to contain dominant Unc's that have a recessive lethal 
phenotype.  Several of these mutations have been segregated away from 
n490; they are muscle defective as heterozygotes and are inviable as 
homozygotes.  Finally, two additional alleles of unc-15 have been 
identified among our collection of spontaneous revertants.
We hope that these revertants will define new loci involved in 
development and function of the body-wall muscle and provide 
additional alleles of the already identified genes.