The contribution of AAUAAA and the upstream element UUUGUA to the efficiency of mRNA 3'-end formation in plants.
AUTOR(ES)
Rothnie, H M
RESUMO
The requirement for sequence specificity in the AAUAAA motif of the cauliflower mosaic virus (CaMV) polyadenylation signal was examined by saturation mutagenesis. While deletion of AAUAAA almost abolished processing at the CaMV polyadenylation site, none of the 18 possible single base mutations had a dramatic effect on processing efficiency. The effect of replacing all six nucleotides simultaneously varied depending on the sequence used, but some replacements were as detrimental as the deletion mutant. Taken together, these results confirm that AAUAAA is an essential component of the CaMV polyadenylation signal, but indicate that a high degree of sequence variation can be tolerated. A repeated UUUGUA motif was identified as an important upstream accessory element of the CaMV polyadenylation signal. This sequence was able to induce processing at a heterologous polyadenylation site in a sequence-specific and additive manner. The effect of altering the spacing between this upstream element and the AAUAAA was examined; moving these two elements closer together or further apart reduces the processing efficiency. The upstream element does not function to signal processing at the CaMV polyadenylation site if placed downstream of the cleavage site. Analysis of further upstream sequences revealed that almost all of the 200 nt fragment required for maximal processing contributes positively to processing efficiency. Furthermore, isolated far upstream sequences distinct from UUUGUA were also able to induce processing at a heterologous polyadenylation site.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=395075Documentos Relacionados
- Upstream sequences other than AAUAAA are required for efficient messenger RNA 3'-end formation in plants.
- Intron status and 3′-end formation control cotranscriptional export of mRNA
- Identification of a sequence element on the 3' side of AAUAAA which is necessary for simian virus 40 late mRNA 3'-end processing.
- The relationship between the prothrombin upstream sequence element and the G20210A polymorphism: the influence of a competitive environment for mRNA 3′-end formation
- Signals sufficient for 3'-end formation of yeast mRNA.