E1392 (
nuc-1,X) lacks the principal endodeoxyribonuclease. When determined on crude sonicates by an assay sensitive to endolytic cleavage of DNA (e.g. the spectrophotometric method of Kunitz, reviewed in Prog. in Nucl. Acid Res. 1 85 (ed Cantoni and Davies, 1967)), the DNase activity is well under 1% of that in N2. Feulgen staining reveals stranded material in the gut, persistent DNA from programmed cell deaths, and extruded polar bodies accumulating in the gonads of old animals; this suggests that a single endo-DNase is used both in the gut and in the tissues of C. elegans. There is no visible phenotype. The map position is: [See Figure 1] The endo-DNase of N2 is equally active in the presence of Mg++ and of EDTA