Polyadenylation of RNA in vitro in Isolated Chromatin and Nuclei

Abstract

Poly(A) is added post‐transcriptionally to RNA transcribed in vitro by endogenous form B DNA‐dependent RNA polymerase bound to the template in isolated nuclei or chromatin. It is also added to processed fragments of the products from α‐amanitin‐resistant RNA polymerases A and/or C. The poly(A) segments are of similar size to those found in nuclear RNA pulse‐labelled in vivo and are added onto the 3′ terminus of RNA chains (whether pre‐existing, completed during the incubation in vitro or created by fragmentation of larger RNA transcripts). That poly(A) addition is not directly mediated by any of the nuclear DNA‐dependent RNA polymerases is shown by the differential sensitivities of RNA and poly(A) syntheses to increasing ionic strength and transcriptional inhibitors such as the exotoxin from Bacillus thuringiensis. Copyright © 1975, Wiley Blackwell. All rights reserved