The role of cleavage of cell structures during apoptosis

In this work we have studied the behavior of some cell structures, such as actin, tubulin and chromatin during apoptosis induced in F9 cells after ret inoic acid treatment. In this experimental model, all defined steps of morp hological changes described for apoptosis are observed. The correlation bet ween a partial maintenance of F-actin and microtubular structures and the s patial distribution of F-actin suggests a possible relationship between thi s molecule and the characteristic shape changes observed in apoptosis. Addi tionally, the disposition of monomeric G-actin suggests a possible relation ship between the fragmentation of this molecule and the cleavage of DNA. Th e analysis of the U2af1-rs1 specific sequence shows that the internucleosom al fragmentation observed in this gene is randomly produced during apoptosi s and is not dependent of demethylation status. The results obtained confir m that specific cleavage of these cell structures is inherent to the develo pment of the apoptotic process and do not exclude the possibility that prot eolysis of key actin and/or tubulin molecules of the cleavage of specific c hromatin sequences other than the ones analyzed here, could control the dif ferent phases of the apoptotic process.