Double stranded R NA molecules containing a single stranded, capped 5' end and a 3' poly(A) tail were circularized by the poly(A) tail binding protein, the cap binding protein, and a fragment of the adapter protein translation initiation factor eIF4G. The large white particles connecting the two ends of the R N A strand contains these three proteins. This is an example of the work in the laboratory of Alan Sachs in in the Department of Molecular and Cell Biology.