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Uracils at nucleotide position 9-11 are required for the rapid turnover of miR-29 family.

Zhang Z, Zou J, Wang GK, Zhang JT, Huang S, Qin YW, Jing Q - Nucleic Acids Res. (2011)

Bottom Line: Moreover, analysis of published data on microRNA expression profile during development reveals that a substantial subset of microRNAs with the uracil-rich sequence tends to be down-regulated compared to those without the sequence.The effect of uracil-rich sequence on microRNA turnover depends on the sequence context.The present work indicates that microRNAs contain sequence information in the middle region besides the sequence element at both ends.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Changhai Hospital, Shanghai, China.

ABSTRACT
MicroRNAs are endogenous small RNA molecules that regulate gene expression. Although the biogenesis of microRNAs and their regulation have been thoroughly elucidated, the degradation of microRNAs has not been fully understood. Here by using the pulse-chase approach, we performed the direct measurement of microRNA lifespan. Five representative microRNAs demonstrated a general feature of relatively long lifespan. However, the decay dynamic varies considerably between these individual microRNAs. Mutation analysis of miR-29b sequence revealed that uracils at nucleotide position 9-11 are required for its rapid decay, in that both specific nucleotides and their position are critical. The effect of uracil-rich element on miR-29b decay dynamic occurs in duplex but not in single strand RNA. Moreover, analysis of published data on microRNA expression profile during development reveals that a substantial subset of microRNAs with the uracil-rich sequence tends to be down-regulated compared to those without the sequence. Among them, Northern blotting shows that miR-29c and fruit fly bantam possess a relatively rapid turnover rate. The effect of uracil-rich sequence on microRNA turnover depends on the sequence context. The present work indicates that microRNAs contain sequence information in the middle region besides the sequence element at both ends.

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The stability of mature miRNAs varies individually in HeLa cells. MiRNA mimickers were transfected into HeLa cells for 4 h and Northern blotting was used to measure the abundance of miRNAs at the indicated time points.
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Figure 2: The stability of mature miRNAs varies individually in HeLa cells. MiRNA mimickers were transfected into HeLa cells for 4 h and Northern blotting was used to measure the abundance of miRNAs at the indicated time points.

Mentions: Five miRNAs with various expression levels in HeLa were selected for lifespan measurement, including miR-16 with high abundance, let-7a, miR-17 and miR-29b with mediate expression, and miR-34a with no detection (25). Pulse–chase assay was used to measure lifespan of these representative miRNAs mentioned above. Generally the miRNA half life was 12 h or longer (Figure 2). Furthermore, these representative miRNAs possessed distinct characteristic in their dynamic change. MiR-16 did not have apparent decrease in their abundance until the time duration limit (12 h); MiR-34a and miR-17 possessed a moderate turnover rate, with a half life of about 12 h; Let-7a and miR-29b rapidly disappeared, with a half life of 11 and 7 h, respectively (Figure 2). The diversity of decay dynamics of miRNAs raises a question of sequence determinant of their stability.Figure 2.


Uracils at nucleotide position 9-11 are required for the rapid turnover of miR-29 family.

Zhang Z, Zou J, Wang GK, Zhang JT, Huang S, Qin YW, Jing Q - Nucleic Acids Res. (2011)

The stability of mature miRNAs varies individually in HeLa cells. MiRNA mimickers were transfected into HeLa cells for 4 h and Northern blotting was used to measure the abundance of miRNAs at the indicated time points.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105410&req=5

Figure 2: The stability of mature miRNAs varies individually in HeLa cells. MiRNA mimickers were transfected into HeLa cells for 4 h and Northern blotting was used to measure the abundance of miRNAs at the indicated time points.
Mentions: Five miRNAs with various expression levels in HeLa were selected for lifespan measurement, including miR-16 with high abundance, let-7a, miR-17 and miR-29b with mediate expression, and miR-34a with no detection (25). Pulse–chase assay was used to measure lifespan of these representative miRNAs mentioned above. Generally the miRNA half life was 12 h or longer (Figure 2). Furthermore, these representative miRNAs possessed distinct characteristic in their dynamic change. MiR-16 did not have apparent decrease in their abundance until the time duration limit (12 h); MiR-34a and miR-17 possessed a moderate turnover rate, with a half life of about 12 h; Let-7a and miR-29b rapidly disappeared, with a half life of 11 and 7 h, respectively (Figure 2). The diversity of decay dynamics of miRNAs raises a question of sequence determinant of their stability.Figure 2.

Bottom Line: Moreover, analysis of published data on microRNA expression profile during development reveals that a substantial subset of microRNAs with the uracil-rich sequence tends to be down-regulated compared to those without the sequence.The effect of uracil-rich sequence on microRNA turnover depends on the sequence context.The present work indicates that microRNAs contain sequence information in the middle region besides the sequence element at both ends.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Changhai Hospital, Shanghai, China.

ABSTRACT
MicroRNAs are endogenous small RNA molecules that regulate gene expression. Although the biogenesis of microRNAs and their regulation have been thoroughly elucidated, the degradation of microRNAs has not been fully understood. Here by using the pulse-chase approach, we performed the direct measurement of microRNA lifespan. Five representative microRNAs demonstrated a general feature of relatively long lifespan. However, the decay dynamic varies considerably between these individual microRNAs. Mutation analysis of miR-29b sequence revealed that uracils at nucleotide position 9-11 are required for its rapid decay, in that both specific nucleotides and their position are critical. The effect of uracil-rich element on miR-29b decay dynamic occurs in duplex but not in single strand RNA. Moreover, analysis of published data on microRNA expression profile during development reveals that a substantial subset of microRNAs with the uracil-rich sequence tends to be down-regulated compared to those without the sequence. Among them, Northern blotting shows that miR-29c and fruit fly bantam possess a relatively rapid turnover rate. The effect of uracil-rich sequence on microRNA turnover depends on the sequence context. The present work indicates that microRNAs contain sequence information in the middle region besides the sequence element at both ends.

Show MeSH
Related in: MedlinePlus