Worm Breeder's Gazette 2(1): 20
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.
We are starting to study the structure and genetic control of the C. elegans cuticle. Cuticles free of most contaminating tissue can be obtained by gentle homogenization or sonication followed by extensive washing with or without SDS. Such cuticles reveal many structural features in phase contrast observation. Cuticle material not only covers the outer surface but continues into the anal opening and the lining of the pharynx. The pharynx apparently also has a lining of SDS-resistant material separating it from the body proper. The cuticle appears to be composed of two layers which are held together by 'struts'. The struts form a quite regular pattern consisting of a double row at the boundary between the annulae. Mild treatments with Pronase or Collagenase appear to act most readily by breaking the struts resulting in the formation of 'double-bags'. Continued treatment results in the dissolution of the inner 'bags'. In addition to being relatively resistant to enzymatic digestion, the outer layer is much more resistant to a variety of non-enzymatic treatments that break non-covalent or disulphide bonds. Adults and dauer larvae have the familiar cuticular structure with annulae and lateral treads ( ridges, alae), although the structure of the tread differs in the two forms. Other larval forms (L3, L4), not yet precisely characterized, lack these structural features. We are about to attempt chemical characterization of the isolated cuticle. The cuticles of dumpy, roller and blister mutants display abnormal cuticular features. In blister mutants the blisters form between the two cuticle layers with the struts clearly broken or missing. The cuticles removed from roller animals are helically twisted, in some cases these cuticles physically curl up even more after the animal is removed. The annulae are not arranged at right angles to the treads as in a normal animal. Mutants with an extreme roller phenotype, and some dumpies, have aberrant treads displaying multiple loops and breaks. These observations encourage us in our suspicion that at least some of the genes that generate these phenotypes are concerned with cuticle formation. Unsolicited gifts of newly isolated roller or blister mutants will be gratefully accepted.