This was unexpected since existing mutations affecting enclosure have primarily a zygotic focus. Surprisingly, we recovered no mutants with a true Zen phenotype. All zygotic mutations identified in the screen enclosed successfully and thus are classified as Zels. Since both ts and cs mutations were isolated, conditional screens for Mels of each type could be carried out. Certainly it should be possible to screen to saturation for Mels that affect enclosure.
Some mutants have developmental defects in processes other than enclosure.
These defects may help to determine the normal function of these genes. In collaboration with Christina Thomas , a graduate student in the Hardin lab, we have shown that in jc7 animals some muscle cells fail to migrate to their normal position, suggesting that jc7 animals may have a general cell migration defect. Some alleles may reveal specific behaviors of different epidermal cells during enclosure. In jc1 and jc14 mutants, enclosure of the anterior leading cells is specifically disrupted, resulting in a phenotype that is reminiscent of the defects in mutants for the C. elegans cadherin homologue, hmr-1 . These results suggest there may be distinct molecular mechanisms underlying the enclosure of anterior and posterior ventral epidermis.