action ▁of ▁these ▁regions ▁is ▁called ▁book mark ing , ▁which ▁is ▁an ▁ep igen etic ▁mechanism ▁believed ▁to ▁be ▁important ▁for ▁transm itting ▁to ▁daughter ▁cells ▁the ▁" memory " ▁of ▁which ▁gen es ▁were ▁active ▁prior ▁to ▁entry ▁into ▁mit osis . ▁This ▁book mark ing ▁mechanism ▁is ▁needed ▁to ▁help ▁transmit ▁this ▁memory ▁because ▁trans cription ▁ce ases ▁during ▁mit osis . ▁ ▁Ch rom atin ▁and ▁burst s ▁of ▁trans cription ▁ ▁Ch rom atin ▁and ▁its ▁interaction ▁with ▁en zym es ▁has ▁been ▁research ed , ▁and ▁a ▁conclusion ▁being ▁made ▁is ▁that ▁it ▁is ▁relevant ▁and ▁an ▁important ▁factor ▁in ▁gene ▁expression . ▁Vincent ▁G . ▁All f rey , ▁a ▁professor ▁at ▁Rock ef eller ▁University , ▁stated ▁that ▁R NA ▁synth esis ▁is ▁related ▁to ▁hist one ▁ac et yl ation . ▁The ▁l ys ine ▁am ino ▁acid ▁attached ▁to ▁the ▁end ▁of ▁the ▁hist ones ▁is ▁posit ively ▁charged . ▁The ▁ac et yl ation ▁of ▁these ▁t ails ▁would ▁make ▁the ▁chrom atin ▁ends ▁neutral , ▁allowing ▁for ▁DNA ▁access . ▁ ▁When ▁the ▁chrom atin ▁de cond enses , ▁the ▁DNA ▁is ▁open ▁to ▁entry ▁of ▁mole cular ▁mach in ery . ▁Fl uct u ations ▁between ▁open ▁and ▁closed ▁chrom atin ▁may ▁contribute ▁to ▁the ▁dis continu ity ▁of ▁trans cription , ▁or ▁trans cription al ▁burst ing . ▁ ▁Other ▁factors ▁are ▁probably ▁involved , ▁such ▁as ▁the ▁association ▁and ▁dis soci ation ▁of ▁trans cription ▁factor ▁complex es