. ▁NR G 1 ▁signal ing ▁is ▁not , ▁however , ▁required ▁for ▁gli al ▁different iation ▁from ▁the ▁neural ▁cr est . ▁ ▁NR G 1 ▁plays ▁important ▁roles ▁in ▁the ▁development ▁of ▁neural ▁cr est ▁derivatives . ▁It ▁is ▁required ▁for ▁neural ▁cr est ▁cells ▁to ▁migr ate ▁past ▁the ▁site ▁of ▁d ors al ▁root ▁gang lia ▁to ▁find ▁the ▁vent ral ▁regions ▁of ▁sympath etic ▁gang li ogen esis . ▁It ▁is ▁also ▁an ▁essential ▁ax on - der ived ▁surv ival ▁factor ▁and ▁a ▁mit ogen ▁for ▁Schw ann ▁cell ▁prec urs ors . ▁It ▁is ▁found ▁in ▁the ▁d ors al ▁root ▁gang l ion ▁and ▁motor ▁neur ons ▁at ▁the ▁point ▁in ▁time ▁that ▁Schw ann ▁cell ▁prec urs ors ▁begin ▁to ▁populate ▁sp inal ▁n erves ▁and ▁therefore ▁influ ences ▁Schw ann ▁cell ▁surv ival . ▁In ▁emb ry onic ▁n erves , ▁the ▁transm emb rane ▁III ▁is o form ▁likely ▁is ▁the ▁primary ▁variant ▁of ▁NR G 1 ▁responsible ▁for ▁surv ival ▁signals . ▁In ▁m ice ▁that ▁lack ▁the ▁transm emb rane ▁III ▁is o form , ▁Schw ann ▁cell ▁prec urs ors ▁are ▁eventually ▁elimin ated ▁from ▁sp inal ▁n erves . ▁ ▁Form ation ▁of ▁my elin ▁she ath ▁ ▁P 0 ▁ ▁My elin ▁protein ▁zero ▁( P 0 ) ▁is ▁a ▁cell - ad hes ion ▁mole c ule ▁belonging ▁to ▁the ▁imm un og lob ul in ▁super family ▁and ▁is ▁the ▁major ▁component ▁of ▁peri pher