Microinjection of anti-p21 antibodies induces senescent Hs68 human fibroblasts to synthesize DNA but not to divide.

Human Fibroblasts to Synthesize DNA but not To Divide Microinjection of Anti-p21 Antibodies Induces Senescent Hs68

Replicative senescence is characterized by irreversible growth arrest and has been defined by four genetic complementation groups. One of these groups is associated with the predominance of underphosphorylated, growth-suppressive retinoblastoma tumor suppressor protein (pRb). Although certain members of the cyclin-dependent kinase (cdk)/cyclin family, some of which phosphorylate pRb, are undere...

Microinjection of Anti-p53 Antibodies in Senescent Human Fibroblasts by Reinitiation of DNA Synthesis and Cell Division

Antibody microinjection reveals an essential role for human polo-like kinase 1 (Plk1) in the functional maturation of mitotic centrosomes

Mammalian polo-like kinase 1 (Plk1) is structurally related to the polo gene product of Drosophila melanogaster, Cdc5p of Saccharomyces cerevisiae, and plo1+ of Schizosaccharomyces pombe, a newly emerging family of serine-threonine kinases implicated in cell cycle regulation. Based on data obtained for its putative homologues in invertebrates and yeasts, human Plk1 is suspected to regulate some...

DNA methyltransferase inhibition in normal human fibroblasts induces a p21-dependent cell cycle withdrawal.

Maintenance of methylation patterns in the mammalian genome by DNA (cytosine-5) methyltransferases (DNAMeTase) is required for normal cell and tissue function. Inhibition of DNAMeTase in cultured cells induces the expression of p21, a cyclin-dependent kinase (Cdk) inhibitor critical for cells to enter replicative senescence. We investigated the effects of DNAMeTase inhibition in normal human fi...

p21 Plays a Critical Role in Modulating Senescence Through Changes of DNA Methylation

It has been reported that genomic DNA methylation decreases gradually during cell culture and an organism’s aging. However, less is known about the methylation changes of age-related specific genes in aging. p21 Cip1 and p16 are cyclin-dependent kinase (Cdk) inhibitors that are critical for the replicative senescence of normal cells. In this study, we show that p21 and p16 have different methyl...