Worm Breeder's Gazette 11(5): 27

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.

Cloning and Sequencing of the C. elegans Cu-Zn Superoxide Dismutase

P.L. Larsen

Figure 1

I am interested in testing the hypothesis that one of the primary 
causes of aging is the accumulation of cellular damage.  Previous 
studies have established a strong correlation between oxidative damage 
and aging, thus I am focusing on this type of damage.  One approach is 
to increase the activity of an enzyme that is known to protect cells 
from oxidative damage via recombinant DNA technology.  I have chosen 
to initially use the enzyme Cu-Zn superoxide dismutase (SOD) which is 
a primary defense against free radicals.  As a first step I have 
cloned the C.  elegans Cu-Zn SOD gene in order to increase the gene 
copy number by an extrachromosomal array in transgenic animals.
The Cu-Zn SOD has been cloned and sequenced from several organisms 
and they are highly homologous.  Two degenerate oligonucleotides were 
designed from the highly conserved regions, and the oligonucleotides 
were used as probes to screen S.  Kim's cDNA library.  Sequence 
analysis verified that the Cu-Zn SOD gene was isolated.  An alignment 
of the deduced coding region is presented below.  Uppercase residues 
denote an identity with C.  elegans and at least one other organism 
listed.  Bold residues are conserved in all fifteen eukaryotes for 
which protein sequence data are available.
[See Figure 1]
The SOD cDNA was used to determine its chromosomal location by 
hybridization to a YAC polytene filter (borrowed from the Horvitz lab).
The SOD gene is on chromosome II near tra-2 and unc-104.  I am 
presently analyzing existing mutants in this region to determine 
whether or not any are SOD mutations.
Initial transgenic strains will be constructed by microinjection of 
the SOD gene under the control of its own promotor.  These strains 
will be tested for increased SOD activity and their lifespan will be 
determined.  It is expected that SOD is expressed in all cells so the 
promotor may be of general use.
I thank A.  Varshavsky, in whose laboratory the bulk of this work 
has been carried out, for support and helpful discussions.  Supported 
by NIH grant to A.  V.  (AG08991).  I also thank D.  Riddle in whose 
laboratory the work is currently in progress.

Figure 1