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. 1998 Dec;18(12):7537–7545. doi: 10.1128/mcb.18.12.7537

FIG. 2.

FIG. 2

FIG. 2

The AU-rich region from the Xenopus c-myc II 3′-UTR directs RNA deadenylation. (A) Poly(A)+ Xmyc (958 nt) and Xglob (749 nt) transcripts were cytoplasmically coinjected into stage VI oocytes. RNA was isolated at the indicated times (in hours) following injection. (B) Poly(A)+ Xmyc and Xglob transcripts (top) or poly(A)+ Xmyc-M1,2,3 and Xglob transcripts (bottom) were coinjected cytoplasmically into fertilized eggs immediately following fertilization. RNA was isolated at the indicated times (in hours) following fertilization. (C) RNase A treatment was used to determine whether the shortening of the Xmyc transcript in fertilized eggs (as seen in panel B, top) was due to poly(A) tail loss. Lane 1, pBR322 MspI DNA marker; lane 2, uninjected [32P]ATP-labelled poly(A)+ Xmyc transcript treated with RNase A; lane 3, uninjected [32P]ATP-labelled poly(A)− Xmyc transcript treated with RNase A; lane 4, 5,000 cpm of RNA isolated from fertilized eggs 0 h after injection with [32P]ATP-labelled poly(A)+ Xmyc transcript treated with RNase A; lane 5, 5,000 cpm of RNA isolated from fertilized eggs 8 h after injection with [32P]ATP-labelled poly(A)+ Xmyc transcript treated with RNase A. Quantitative analysis by PhosphorImager of the distribution of counts per minute in lane 5 relative to lane 4 revealed that incubation for 8 h resulted in a 60 to 70% reduction of the signal for the poly(A) tail relative to common background RNase A digestion products (indicated by brackets). In panels A and B, each lane contains RNA isolated from the equivalent of two injected oocytes or embryos.