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Transcripts synthesized by RNA polymerase III can be polyadenylated in an AAUAAA-dependent manner

Olga R Borodulina1, Dmitri A Kramerov

  • 1Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.

RNA (New York, N.Y.)
|July 29, 2008
PubMed

Insights

Short interspersed elements (SINEs) can be polyadenylated by RNA polymerase III, contrary to prior understanding. Polyadenylation enhances the stability of these SINE transcripts within cells.

Area of Science:

  • Molecular Biology
  • RNA Biology
  • Gene Expression

Background:

  • Eukaryotic messenger RNAs (mRNAs) typically possess a 3' poly(A) tail, crucial for stability and translation.
  • Polyadenylation, the addition of this tail, is generally considered dependent on the polyadenylation signal (AAUAAA) and RNA polymerase II transcription.
  • The protein complex for polyadenylation is intrinsically linked to RNA polymerase II during gene transcription.

Purpose of the Study:

  • To investigate the polyadenylation of short interspersed elements (SINEs) transcripts.
  • To determine if RNA polymerase III-transcribed RNAs can be polyadenylated.
  • To assess the impact of polyadenylation on SINE RNA stability.

Main Methods:

  • HeLa cells were transfected with constructs for SINEs B2 and VES, with and without the AAUAAA polyadenylation signal.
  • Analysis of SINE transcripts to detect the presence of poly(A) tails.
  • Comparison of the stability of polyadenylated and non-polyadenylated B2 RNA in cells.

Main Results:

  • Short interspersed elements (SINEs) transcripts generated by RNA polymerase III were found to be polyadenylated.
  • Polyadenylation of SINEs occurred in an AAUAAA-dependent manner.
  • Polyadenylated B2 SINE RNA exhibited significantly greater stability in cells compared to its non-polyadenylated counterpart.

Conclusions:

  • The findings challenge the established view that only RNA polymerase II transcripts undergo polyadenylation.
  • RNA polymerase III-transcribed SINEs can be polyadenylated, indicating a broader scope for this regulatory mechanism.
  • Polyadenylation significantly enhances the stability of SINE RNAs, suggesting a role in their cellular function and persistence.

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