mRNA Formation: 3′ End

Abstract

The 3′ end of eukaryotic messenger ribonucleic acid (mRNA) is not generated by termination of transcription but by processing of the primary transcript. Posttranscriptional 3′ end formation almost always consists of cleavage of an internal phosphodiester bond, followed by the addition of a poly(A) tail to the upstream cleavage fragment.

Keywords: mRNA; poly(A) tails; RNA processing

Figure 1.

An outline of the 3′ processing reaction. The pre‐mRNA is synthesized by RNA polymerase II (POL II) by transcription of the gene sequence. The 5′ cap, abbreviated GpppG, is added very soon after the initiation of transcription. Cleavage 3′ of the AAUAAA sequence can occur either while transcription is still going on or after termination. The upstream cleavage fragment is polyadenylated, whereas the downstream fragment is degraded. Most eukaryotic mRNA precursors are also spliced; this is not depicted here.

Figure 2.

A model of the cleavage complex. The arrangement of poly(A) polymerase (PAP), cleavage factors I and II (CF I and CF II) on the RNA is not known. Only two subunits of CF II are shown. DSE, downstream element. Reprinted from Wahle E and Kühn U (1997) Progress in Nucleic Acid Research and Molecular Biology57: 41–71, by permission of Academic Press, with modifications.

Figure 3.

A model of the poly(A) elongation complex. Reprinted from Wahle E and Kühn U (1997) Progress in Nucleic Acid Research and Molecular Biology57: 41–71, by permission of Academic Press, with modifications.

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Further Reading

Dominski Z and Marzluff WF (1999) Formation of the 3′ end of histone mRNA. Gene 239: 1–14.

Marzluff WF and Duronio RJ (2002) Histone mRNA expression: multiple levels of cell cycle regulation and important developmental consequences. Current Opinion in Cell Biology 14: 692–699.

Proudfoot NJ, Furger A and Dye MJ (2002) Integrating mRNA processing with transcription. Cell 108: 501–512.

Wahle E and Rüegsegger U (1999) 3′‐End processing of pre‐mRNA in eukaryotes. FEMS Microbiological Reviews 23: 277–295.

Wickens M, Goodwin EB, Kimble J, Strickland S and Hentze M (2000) Translational control of developmental decisions. In: Sonenberg N, Hershey JWB and Mathews MB (eds) Translational Control of Gene Expression. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press.

Zhao J, Hyman L and Moore C (1999) Formation of mRNA 3′ ends in eukaryotes: Mechanism, regulation, and interrelationships with other steps in mRNA synthesis. Microbiology and Molecular Biology Reviews 63: 405–445.

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How to Cite close
Wahle, Elmar(May 2005) mRNA Formation: 3′ End. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0003936]