▁of ▁the ▁AD AR ▁family ▁AD AR s ▁ 1 - 3 , ▁with ▁AD AR 1 ▁and ▁AD AR 2 ▁being ▁the ▁only ▁en zym atically ▁active ▁members . ▁AD AR 3 ▁is ▁thought ▁to ▁have ▁a ▁regul atory ▁role ▁in ▁the ▁brain . ▁AD AR 1 ▁and ▁AD AR 2 ▁are ▁widely ▁expressed ▁in ▁t issues , ▁whereas ▁AD AR 3 ▁is ▁restricted ▁to ▁the ▁brain . ▁The ▁double - str and ed ▁regions ▁of ▁R NA ▁are ▁formed ▁by ▁base - pair ing ▁between ▁resid ues ▁in ▁the ▁close ▁to ▁region ▁of ▁the ▁editing ▁site , ▁with ▁resid ues ▁usually ▁in ▁a ▁neighbor ing ▁intr on , ▁but ▁can ▁be ▁an ▁ex onic ▁sequence . ▁The ▁region ▁that ▁base - p airs ▁with ▁the ▁editing ▁region ▁is ▁known ▁as ▁an ▁Edit ing ▁Com plement ary ▁Se quence ▁( E CS ). ▁AD AR s ▁bind ▁interact ▁directly ▁with ▁the ▁ds R NA ▁substr ate ▁via ▁their ▁double - str and ed ▁R NA ▁binding ▁domains . ▁If ▁an ▁editing ▁site ▁occurs ▁within ▁a ▁coding ▁sequence , ▁the ▁result ▁could ▁be ▁a ▁cod on ▁change . ▁This ▁can ▁lead ▁to ▁translation ▁of ▁a ▁protein ▁is o form ▁due ▁to ▁a ▁change ▁in ▁its ▁primary ▁protein ▁structure . ▁Therefore , ▁editing ▁can ▁also ▁alter ▁protein ▁function . ▁A ▁to ▁I ▁editing ▁occurs ▁in ▁a ▁non c oding ▁R NA ▁sequences ▁such ▁as ▁intr ons , ▁un trans l ated ▁regions ▁( UT R s ), ▁L INE s , ▁S INE s