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Adenylation of plant miRNAs.

Lu S, Sun YH, Chiang VL - Nucleic Acids Res. (2009)

Bottom Line: We also show that a significant portion of the isolated miRNAs contains, at the 3'-end, one or a few post-transcriptionally added adenylic acid residues, which are distinct in length from the polyadenylate tail added to other plant RNAs for exosome-mediated degradation.It indicates that addition of adenylic acid residues on the 3'-end plays a negative role in miRNA degradation.Our results provide new information for understanding the mechanism of miRNA degradation.

View Article: PubMed Central - PubMed

Affiliation: Department of Forestry and Environmental Resources, College of Natural Resources, North Carolina State University, Raleigh, NC 27695, USA. slu@unity.ncsu.edu

ABSTRACT
The modification or degradation of RNAs including miRNAs may play vital roles in regulating RNA functions. The polyadenylation- and exosome-mediated RNA decay is involved in the degradation of plant RNAs including the primary miRNA processing intermediates. However, plant miRNA levels are not affected by exosome depletion. Here, we report the cloning of a large number of 5' and/or 3' truncated versions of the known miRNAs from various tissues of Populus trichocarpa (black cottonwood). It suggests that plant miRNAs may be degraded through either 5' to 3' or 3' to 5' exonucleolytic digestion. We also show that a significant portion of the isolated miRNAs contains, at the 3'-end, one or a few post-transcriptionally added adenylic acid residues, which are distinct in length from the polyadenylate tail added to other plant RNAs for exosome-mediated degradation. Using an in vitro miRNA degradation system, where synthesized miRNA oligos were degraded in extracts of P. trichocarpa cells, we revealed that the adenylated miRNAs were degraded slower than others without adenylation. It indicates that addition of adenylic acid residues on the 3'-end plays a negative role in miRNA degradation. Our results provide new information for understanding the mechanism of miRNA degradation.

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MiRNAs with post-transcriptionally added adenylic acid residues. Total counts of adenylated miRNAs for 12 families isolated from P. trichocarpa are shown. The number of adenylic acid residues added on the 3′-end of a miRNA sequence ranges from one to seven, respectively.
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Figure 1: MiRNAs with post-transcriptionally added adenylic acid residues. Total counts of adenylated miRNAs for 12 families isolated from P. trichocarpa are shown. The number of adenylic acid residues added on the 3′-end of a miRNA sequence ranges from one to seven, respectively.

Mentions: The number of adenylic acid residues added on the 3′-end of a miRNA ranges from one to seven (Figure 1). About half of the adenylated miRNAs have one post-transcriptionally added residue. The percentages for miRNAs with two and three post-transcriptionally added adenylic acid residues are 26% and 15%, respectively. These short tails of adenylic acid residues are obviously distinct in length from the long poly(A) tails added on the 3′-end of other RNAs that are consequently degraded by an exosome (19). Addition of one adenylic acid residue on the 3′-ends was previously observed for other small RNAs, such as signal recognition particle (SRP) RNA and U2 snRNA isolated from yeast, frog and human cells (20,21), suggesting that it occurs among a variety of small RNA species of eukaryotes. However, the function of this adenylation has poorly been characterized.Figure 1.


Adenylation of plant miRNAs.

Lu S, Sun YH, Chiang VL - Nucleic Acids Res. (2009)

MiRNAs with post-transcriptionally added adenylic acid residues. Total counts of adenylated miRNAs for 12 families isolated from P. trichocarpa are shown. The number of adenylic acid residues added on the 3′-end of a miRNA sequence ranges from one to seven, respectively.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665221&req=5

Figure 1: MiRNAs with post-transcriptionally added adenylic acid residues. Total counts of adenylated miRNAs for 12 families isolated from P. trichocarpa are shown. The number of adenylic acid residues added on the 3′-end of a miRNA sequence ranges from one to seven, respectively.
Mentions: The number of adenylic acid residues added on the 3′-end of a miRNA ranges from one to seven (Figure 1). About half of the adenylated miRNAs have one post-transcriptionally added residue. The percentages for miRNAs with two and three post-transcriptionally added adenylic acid residues are 26% and 15%, respectively. These short tails of adenylic acid residues are obviously distinct in length from the long poly(A) tails added on the 3′-end of other RNAs that are consequently degraded by an exosome (19). Addition of one adenylic acid residue on the 3′-ends was previously observed for other small RNAs, such as signal recognition particle (SRP) RNA and U2 snRNA isolated from yeast, frog and human cells (20,21), suggesting that it occurs among a variety of small RNA species of eukaryotes. However, the function of this adenylation has poorly been characterized.Figure 1.

Bottom Line: We also show that a significant portion of the isolated miRNAs contains, at the 3'-end, one or a few post-transcriptionally added adenylic acid residues, which are distinct in length from the polyadenylate tail added to other plant RNAs for exosome-mediated degradation.It indicates that addition of adenylic acid residues on the 3'-end plays a negative role in miRNA degradation.Our results provide new information for understanding the mechanism of miRNA degradation.

View Article: PubMed Central - PubMed

Affiliation: Department of Forestry and Environmental Resources, College of Natural Resources, North Carolina State University, Raleigh, NC 27695, USA. slu@unity.ncsu.edu

ABSTRACT
The modification or degradation of RNAs including miRNAs may play vital roles in regulating RNA functions. The polyadenylation- and exosome-mediated RNA decay is involved in the degradation of plant RNAs including the primary miRNA processing intermediates. However, plant miRNA levels are not affected by exosome depletion. Here, we report the cloning of a large number of 5' and/or 3' truncated versions of the known miRNAs from various tissues of Populus trichocarpa (black cottonwood). It suggests that plant miRNAs may be degraded through either 5' to 3' or 3' to 5' exonucleolytic digestion. We also show that a significant portion of the isolated miRNAs contains, at the 3'-end, one or a few post-transcriptionally added adenylic acid residues, which are distinct in length from the polyadenylate tail added to other plant RNAs for exosome-mediated degradation. Using an in vitro miRNA degradation system, where synthesized miRNA oligos were degraded in extracts of P. trichocarpa cells, we revealed that the adenylated miRNAs were degraded slower than others without adenylation. It indicates that addition of adenylic acid residues on the 3'-end plays a negative role in miRNA degradation. Our results provide new information for understanding the mechanism of miRNA degradation.

Show MeSH
Related in: MedlinePlus