RNA transport pathway rRNA nuclear export pathway 2015-02-12T15:36:24Z PW:0001619 The pathway whereby the pre- ribosomal particles, pre-40S and pre-60S containing three of the four rRNA genes, are exported to the cytoplasm. The two particles follow independent transport routes, embedded within ribosome biogenesis. The 5S rRNA transcribed by RNA polymerase III is independently transported to be delivered to the ribosome immediately or from a cytoplasmic pool. pathway vpetri