Figure 1. Overview of retroviral transcription and RNA processing: Typical proviral structure (A) with identical 5′ and 3′ LTRs.

Figure 1

Overview of retroviral transcription and RNA processing: Typical proviral structure (A) with identical 5′ and 3′ LTRs. Genes illustrated above the line are shared by all replication-competent retroviruses. The horizontal arrow marks the start site of transcription. The vertical arrow denotes the site of 3′-end processing and polyadenylation in the RNA transcript. All viruses synthesize full-length genomic RNA (B). The subgenomic-sized transcripts illustrate some of the possible products of alternative splicing. In simple retroviruses (C), only a single splice donor or, occasionally, two splice acceptors are used. In complex viruses (D), multiple spliced products are found. (TR) Transcriptional control elements that function in DNA; (PA) polyadenylation and 3′-end processing signals that function in RNA; (CAP) posttranscriptional modification of 5′ termini of all transcripts; (SD and SA) spliced donor and acceptor signals for splicing (C); (AAA) polyadenylation of 3′ termini of all transcripts.

From: Synthesis and Processing of Viral RNA

Cover of Retroviruses
Retroviruses.
Coffin JM, Hughes SH, Varmus HE, editors.
Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 1997.
Copyright © 1997, Cold Spring Harbor Laboratory Press.

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