Chromosome condensing ability of mitotic proteins diminished by the substitution of phenylalanine with parafluorophenylalanine.

One of the objectives of this study was to develop a method for the reversible arrest of HeLa cells in G2 phase by using p-fluorophenylalanine (FPA), an analog of phenylalanine. Addition of 0.5 mM of FPA to synchronized HeLa cells during the middle of S phase, i.e., 4 h after reversal of the double thymidine block, arrested 93% of the cells in G2 phase. After the drug was removed from the medium, these G2 cells proceeded into mitosis synchronously. The results of the study also indicate that incorporation of FPA into mitotic proteins results in the inhibition of chromosome condensation as assayed by their ability to induce premature chromosome condensation in G1 HeLa cells and meiotic maturation in amphibian oocytes.