Failure of centromere separation leads to formation of diplochromosomes in next mitosis in okadaic acid treated HeLa cells.
High concentrations of okadaic acid, sufficient to inhibit phosphatase 1 and 2A activities, induces formation of diplochromosomes in HeLa cells. It has been shown that this is due to a failure of sister chromatid separation in earlier mitosis in the presence of okadaic acid in the medium and not due to bypassing of mitosis (endoreduplication). Moreover, it has been demonstrated that the sister chromatid adherence does not depend on any under-replicated chromatin segment shared by the sister chromatids which might happen in okadaic acid induced premature mitosis, but due to the failure of the centromeres to separate at metaphase-anaphase transition. The role of phosphatase 1 in sister chromatid separation has been discussed.
Ghosh
S
S
Research Program IV, German Cancer Research Center, Heidelberg.
Paweletz
N
N
Schroeter
D
D
D002503:Centromere / Q000187:drug effects* / Q000502:physiology; D002842:Chromatids / Q000187:drug effects; D002869:Chromosome Aberrations; D004988:Ethers, Cyclic / Q000494:pharmacology*; D016195:G2 Phase; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D009630:Nondisjunction, Genetic; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D054645:Protein Phosphatase 1; D016196:S Phase; D013936:Thymidine / Q000494:pharmacology
D004988:Ethers, Cyclic; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D013936:Thymidine