HumanDNApolymerase E isexpressedduring cell proliferation ina mannercharacteristic of plicative DNApolymerases

Inorder toshedligt ontherole ofmammalanDNA polymnere ewestudied theexpessin ofmRNAfor thehunmnenzyme during cell proliferation andduring thecell cycle. Steady-state levels ofmRNAencoding DNApolymerase ew elevadramatically when quescent (GO) cells werestimulated toproliferate (G1/S) Inasimilar manner toffose ofDNApolymerase a.Messaelevels ofDNApolymeraewereunchanged Insimilar e. Theconcentration of immunoreactive DNApolymerase £wasalsomuch higher inextracts fromproliferating fissues thanin thosefromnon-prol tingorslowly prolifemting tissues. Thelevel ofDNA polymerase emRNA in actively cyclhing cells synchronized wvinocodrazole andincells f Ionaedbycounvterfo centrifugal elutriation showedweaker variation, beingatIts highest attheG1/Sstageboundary. Theresults presented strongly suggest thatmammalian DNA polymerase £Isinvolved Inthereplication ofchromosomalDNAand/or Inarepair process thatmaybe substantially activated during tereplication ofchromosomal DINA. Ahypothetical role forDNApolymeraseeina repair process coupled toreplication is discussed.