CN K ▁gene . ▁ ▁Function ▁▁ ▁The ▁protein ▁encoded ▁by ▁this ▁gene ▁is ▁a ▁member ▁of ▁the ▁trans cription ▁cycl in ▁family . ▁These ▁cycl ins ▁may ▁reg ulate ▁trans cription ▁through ▁their ▁association ▁with ▁and ▁activation ▁of ▁cycl in - dependent ▁kin ases ▁( CD K s ) ▁through ▁conform ational ▁changes . ▁Activ ation ▁of ▁CD K s ▁through ▁their ▁cycl in ▁partner , ▁creates ▁kin ase ▁complex es ▁that ▁will ▁activ ate ▁target ▁prote ins ▁through ▁ph osph ory lation . ▁Target ed ▁prote ins ▁can ▁then ▁ultimately ▁reg ulate ▁dec isions ▁of ▁a ▁cell ' s ▁pro gression ▁within ▁the ▁cell ▁cycle ▁to ▁occur . ▁This ▁gene ▁product ▁may ▁be ▁seen ▁to ▁play ▁a ▁dual ▁role ▁in ▁both ▁reg ulating ▁CD K ▁and ▁R NA ▁polym er ase ▁II ▁( R N AP 2 ) ▁activities . ▁Cy cl in ▁K ▁only ▁uses ▁R NA ▁rec ruit ment ▁to ▁activ ate ▁trans cription . ▁ ▁Inter actions ▁▁ ▁Cy cl in ▁K ▁has ▁been ▁shown ▁to ▁interact ▁with ▁multiple ▁CD K s ▁including ▁CD K 9 ▁and ▁latest ▁CD K 1 2 ▁and ▁CD K 1 3 . ▁R oles ▁include ▁helping ▁to ▁ph osph ory late ▁C - term inal ▁domains ▁of ▁sub un its ▁of ▁R N AP 2 . ▁Cy cl in ▁K ▁is ▁most ▁noted ▁for ▁its ▁associated ▁induction ▁of ▁process ive ▁el ong ation . ▁Also , ▁identified ▁with ▁G 1 ▁and ▁S ▁phase ▁cycl in ▁activity , ▁however ▁functions ▁are ▁not ▁deeply