Worm Breeder's Gazette 7(1): 63

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.

More About L4 & Adult Cuticle Proteins

M. Kusch

SDS-PAGE of L4 and adult soluble cuticle proteins revealed that only 
bands E and H were present in both developmental stages (Cox et al., 
1981.  Dev.  Biol 86: 456-470).  Analysis of these proteins by 2D gels 
shows that 6 spots (corresponding to 3 bands on one-dimensional gels) 
are identical.  One of the spots makes up all of the adult band E and 
most of the L4 band E and has an approximate pI of 4.5.  Four spots 
compose all of band H and have pI's from 3.15-3.3.  The sixth spot has 
a higher molecular weight than 210K and a pI of about 4.  The 
remaining major polypeptides are different with the L4 cuticle 
proteins generally more basic by about 0.5-1 pH unit than the adult 
cuticle proteins.  In addition the major L4 cuticle proteins (H is an 
exception) all appear as single spots on 2D gels, whereas the major 
adult proteins (except E) appear as multiple spots with small charge 
A second difference between L4 and adult cuticle proteins appears 
when native proteins are treated with pepsin.  This enzyme digests 
nonhelical parts of native collagens but leaves helical regions intact.
Purified [35S]-labeled cuticles were extracted with  -
mercaptoethanol in a buffered salt solution to isolate native 
molecules.  The extracted proteins were digested with pepsin in 0.5M 
acetic acid at 6 C and analyzed by SDS-PAGE and fluorography.  The 
major labeled bands from L4 and adult cuticles (presumably 
polypeptides derived from collagen triple helices) had different 
molecular weights.  Each stage has one very prominent polypeptide and 
3-5 less prominent ones, some of which may have the same molecular 
weights in the two developmental stages.