Worm Breeder's Gazette 5(2): 42a
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.
In the wild-type Caenorhabditis ei of the hypodermal syncytium assume an ordered and predictable spatial pattern as new nuclei are added during development (Sulston and Horvitz, Dev. Biol., 56 110 (1977)). These nuclei are displaced by animal contortions but return to equilibrium positions when the distorting force is removed. In the recessive mutant e1753 (LG I), the syncytial nuclei are not permanently anchored and move along the syncytium freely. Defective nuclear attachment is apparent in several other cell types with geometries favorable for observing nuclear displacement. It is possible that all cell types in the animal are affected. The mutant animals are fertile (50-130 progeny) and coordinated. They are slightly small, pale, and short-lived. (This may account for their reduced brood size.) The active movements of the male and female pronuclei following fertilization and the cell lineages appear normal. In addition to nuclear positioning, mitochondrial positioning is disturbed in this mutant. Normally, the shape and precise spatial distribution of mitochondria varies with the metabolic state of the worm. However, in e1753, the mitochondria of the lateral hypodermis are easily seen to move freely. The mitochondria of living worms can be seen by staining in 10 g/ml rhodamine 6G in M9 buffer for 30 minutes (Johnson et al., PNAS 77 990 (February 1980)). The stained worms are placed on an NGM plate with a bacterial lawn and transferred to a microscope slide with a 5% agar pad for immediate viewing by epifluorescence. The worms will remain stained for several hours on the bacterial lawn. This mutation, e1753, may disrupt cytoskeletal elements responsible for the positioning of mitochondria and interphase nuclei.