Why does the RNA polymerase complex in eukaryotes contain a histone acetylase? Solution Eukaryotes have chromatin structure made-up of histone octamer complex. Which makes it more compact and in accessable to transcription, to over come this common problem not only during transcription also during replication these histone Acetylene will Acetylation the histone proteins and make them to release the bound form of DNA into fre form for easy access to enzymes( RNA polymerase)..