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Apoptosis is often accompanied by degradation of chromosomal DNA. CAD, caspase-activated DNase, was identified in 1998 as a DNase that is responsible for this process. In the last several years, mice deficient in the CAD system have been generated. Studies with these mice indicated that apoptotic DNA degradation occurs in two different systems. In one, the DNA fragmentation is carried out by CAD in the dying cells and in the other, by lysosomal DNase II after the dying cells are phagocytosed. Several other endonucleases have also been suggested as candidate effectors for the apoptotic degradation of chromosomal DNA. In this review, we will discuss the mechanism and role of DNA degradation during apoptosis.

Abstract Caspase-activated DNase (CAD) cleaves chromosomal DNA during apoptosis. We determined its genomic structure and identified single-nucleotide polymorphisms (SNPs) within exons 5 and 7, as well as a highly polymorphic dinucleotide repeat of (CT)m(CA)n within the 5' region of the human CAD gene (hCAD). The genomic structure of hCAD presented here, together with information concerning SNPs within the gene, as well as a highly polymorphic (CT)m(CA)n repeat fragment at the hCAD locus, may assist in the construction of genetic maps for exploring gene(s) that play pivotal roles in carcinogenesis. [ABSTRACT FROM AUTHOR]