Elsevier Inc. Eif6 5S rRNA partners ITS1 cleavage/processing ---> pre-60S subunit box C/D 40S subunit ---- 60S subunit 80S ribosome translation pathway 60S subunit start codon scanning translation initiation pathway Mdn1 Gnl2 40S subunit ---> start codon scanning ribosomal proteins, large subunit ---> 60S subunit pre-60S subunit <--> 60S subunit pre-40S subunit ---> 40S subunit RNA helicases in ribosome biogenesis ribosomal proteins, large subunit large subunit maturation ribosomal proteins, small subunit small subnit maturation pre-60S subunit pre-40S subunit ITS1 cleavage/processing 5'-ETS cleavage/processing box H/ACA Nup88 Nup214 GTP Prkcb ---> Eif6 Prkcb ---| Eif6 pre-60S subunit ---- Xpo5 Nup214 ---- Xpo1 Nup214 ---- Nup88 Eri1 ribosomal proteins, small subunit ---> 40S subunit Gnl2 ---| Nmd3 ribosomal proteins, small subunit ---> pre-40S subunit ribosomal proteins, large subunit ---> pre-60S subunit box H/ACA ---> pre-60S subunit box C/D ---> pre-40S subunit box C/D ---> pre-60S subunit box H/ACA ---> pre-40S subunit 28S 5.8S ITS1 cleavage/processing ---> pre-40S subunit 5'-ETS cleavage/processing ---> pre-40S subunit RNA helicases in ribosome biogenesis ---> pre-40S subunit RNA helicases in ribosome biogenesis ---> pre-60S subunit Eri1 ---> 60S subunit Nob1 Nob1 ---> 40S subunit Prkcb RNA polymerase I transcription pathway RNA polymerase III transcription pathway Gnb2l1 Gnb2l1 ---- Prkcb 40S subunit ---- Gnb2l1 60S subunit ---- Eif6 5S ---> pre-60S subunit 5S 5S ---- 5S rRNA partners Ran Xpo5 Nmd3 ---- Xpo1 GTP ---- Ran Nmd3 5.8S ---> large subunit maturation 28S ---> large subunit maturation 18S 40S subunit Xpo1 Nmd3 ---- pre-60S subunit Ltv1 ---- Xpo1 Ltv1 small subnit maturation ---> 40S subunit large subunit maturation ---> 60S subunit 18S ---> small subnit maturation Gnl2 ---- pre-60S subunit Mdn1 ---| Gnl2 Eif6 ---| 80S ribosome