SELECTIVE INHIBITION BY APHIDICOLIN OF THE ACTIVITY OF DNA POLYMERASE ALPHA LEADS TO BLOCKADE OF DNA SYNTHESIS AND CELL DIVISION IN SEA URCHIN EMBRYOS

Abstract

Aphidicolin at 2 .mu.g/ml caused 90% inhibition of mitotic cell division of sea urchin [Hemicentrotus pulcherrimus] embryos at the 1-cell stage. At 40 .mu.g/ml it did not affect meiotic maturational divisions of starfish [Asterias amurensis] oocytes, which do not involve DNA replication. At 2 .mu.g/ml it caused 90% inhibition of incorporation of [3H]-thymidine into DNA of sea urchin embryos but did not affect protein or RNA synthesis even at a higher concentration. At 2 .mu.g/ml it also caused 90% inhibition of the activity of DNA polymerase .alpha., obtained from the nuclear fraction of sea urchin embryos, but did not affect the activity of DNA polymerase .beta. or .gamma.. DNA polymerase .alpha. is apparently responsible for replication of DNA in sea urchin embryos.