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.
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 differences. 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.