PRESENCE OF ZETA-TYPE DNA-POLYMERASE IN EGGS OF THE TELEOST FISH MISGURNUS-FOSSILIS L

A partially purified preparation of DNA polymerase of 5 type was isola ted from eggs of the teleost fish Misgurnus fossilis L. (leach). The e nzyme preparation had high 3'-->5'-exonuclease activity and low proces sivity during synthesis on poly(dA)-dT(10) template. DNA-polymerase ac tivity of the enzyme was inhibited by aphidicolin, but it was resistan t to BuAdATP. Activity and processivity of the enzyme did not increase in the presence of the PCNA protein from calf thymus. The molecular w eight of the catalytic subunit of the DNA polymerase xi was about 75 k D as determined by means of UV light-induced binding of oligonucleotid e to the enzyme. During early stages of leach development the activity of the DNA polymerase xi in embryos increased from 0.2 unit/mg protei n (eggs) to 1.7 units/mg protein (prior to hatching, 40 h of developme nt). The enzymatic properties of the DNA polymerase 5 suggest that it functions in DNA repair.